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All Textbook Solutions for Chemistry by OpenStax (2015-05-04)

What is the limiting reactant in a reaction that produces sodium chloride from 8 g of sodium and 8 g of diatomic chlorine?Which of the postulates of Dalton’s atomic theory explains why we can calculate a theoretical yield for a chemical reaction?A student isolated 25 g of a compound following a procedure that would theoretically yield 81 g. What was his percent yield?A sample of 0.53 g of carbon dioxide was obtained by heating 1.31 g of calcium carbonate. What is the percent yield for this reaction? CaCO3(s)CaO(s)+CO2(s)Freon-12, CCl2F2, is prepared from CCl4 by reaction with HF. The other product of this reaction is HCl. Outline the steps needed to determine the percent yield of a reaction that produces 12.5 g of CCl2F2 from 32.9 g of Cd4. Freon-12 has been banned and is no longer used as a refrigerant because it catalyzes the decomposition of ozone and has a very long lifetime in the atmosphere. Determine the percent yield.Citric acid, C6H5CH3, a component of jams, jellies, and fruity soft drinks, is prepared industrially via fermentation of sucrose by the mold Aspergillus niger . The equation representing this reaction is C12H22O11+H2O+3O22C6H8O7+4H2O What mass of citric acid is produced from exactly 1 metric ton (1.000103kg) of sucrose if the yield is 92.30%?Toluene, C6H5CH3, is oxidized by air under carefully controlled conditions to benzoic acid, C6H5CO2H, which is used to prepare the food preservative sodium benzoate, C6H5CO2Na. What is the percent yield of a reaction that converts 1.000 kg of toluene to 1.21 kg of benzoic acid? 2C6H5CH3+3O22C6H5CO2H+2H2O In a laboratory experiment, the reaction of 3.0 mol of H2 with 2.0 mol of I2 produced 1.0 mol of HI. Determine the theoretical yield in grams and the percent yield for this reaction.Outline the steps needed to solve the following problem, then do the calculations. Ether, (C2H5)2O, which was originally used as an anesthetic but has been replaced by safer and more effective medications, is prepared by the reaction of ethanol with sulfuric acid. 2C2H5OH+H2SO4(C2H5)2O+H2SO4H2O What is the percent yield of ether if 1.17 L (d = 0.7134 g/mL) is isolated from the reaction of 1.500 L of C2H5OH (d = 0.7894 g/mL)?Outline the steps needed to determine the limiting reactant when 30.0 g of propane, C3H8, is burned with 75.0 g of oxygen. Determine the limiting reactant.Outline the steps needed to determine the limiting reactant when 0.50 mol of Cr and 0.75 mol of H3PO4 react according to the following chemical equation. 2Cr+2H3PO42CrPO4+3H2 Determine the limiting reactant.What is the limiting reactant when 1.50 g of lithium and 1.50 g of nitrogen combine to form lithium nitride, a component of advanced batteries, according to the following unbalanced equation? Li+N2Li3N Uranium can be isolated from its ores by dissolving it as UO2( NO3)2, then separating it as solid UO2(C2O4)3H2O. Addition of 0.4031 g of sodium oxalate, Na2C2O4, to a solution containing 1.481 g of uranyl nitrate, UO2( NO3)2, yields 1.073 g of solid UO2(C2O4)3H2O. Na2C2O4+UO2( NO3)2+3H2OUO2(C2O4)3H2O+2NaNO3 Determine the limiting reactant and the percent yield of this reaction.How many molecules of C2H4Cl2 can be prepared from 15C2H4 molecules and 8Cl2 molecules?How many molecules of the sweetener saccharin can be prepared from 30 C atoms, 25 H atoms, 12 0 atoms, 8 S atoms, and 14 N atoms?The phosphorus pentoxide used to produce phosphoric acid for cola soft drinks is prepared by burning phosphorus in oxygen. (a) What is the limiting reactant when 0.200 mol of P4 and 0.200 mol of 02 react according to P4+5O2P4O10 (b) Calculate the percent yield if 10.0 g of P4O10 is isolated from the reaction.Would you agree to buy 1 trillion (1,000,000,000,000) gold atoms for $5? Explain why or why not. Find the current price of gold at http://money.cnn.com/data/commodities/ (1 troy ounce = 31.1 g)What volume of 0.0105-M HBr solution is required to titrate 125 mL of a 0.0100-M Ca(OH)2 solution? Ca(OH)2(aq)+2HBr(aq)CaBr2(aq)+2H2O(l)Titration of a 20.0-mL sample of acid rain required 1.7 mL of 0.08 11 M NaOH to reach the end point. If we assume that the acidity of the rain is due to the presence of sulfuric acid, what was the concentration of sulfuric acid in this sample of rain?What is the concentration of NaCl in a solution if titration of 15.00 mL of the solution with 0.2503 M AgNO3 requires 20.22 mL of the AgNO3 solution to reach the end point? AgNO3(aq)+NaCl(aq)AgCl(s)+NaNO3(aq)In a common medical laboratory determination of the concentration of free chloride ion in blood serum, a serum sample is titrated with a Hg( NO3)2 solution. 2Cl(aq)+Hg( NO3)2(aq)2NO3(aq)+HgCl2(s) What is the CF concentration in a 0.25-mL sample of normal serum that requires 1.46 mL of 8.25104M Hg( HO3)2(aq) to reach the end point?Potatoes can be peeled commercially by soaking them in a 3-M to 6-M solution of sodium hydroxide, then removing the loosened skins by spraying them with water. Does a sodium hydroxide solution have a suitable concentration if titration of 12.00 mL of the solution requires 30.6 mL of 1.65 M HCI to reach the end point?A sample of gallium bromide, GaBr3, weighing 0. 165 g was dissolved in water and treated with silver nitrate, AgNO3, resulting in the precipitation of 0.299 g AgBr. Use these data to compute the %Ga (by mass) GaBr3.The principal component of mothballs is naphthalene, a compound with a molecular mass of about 130 amu, containing only carbon and hydrogen. A 3.000-mg sample of naphthalene burns to give 10.3 mg of CO2. Determine its empirical and molecular formulas.A 0.025-g sample of a compound composed of boron and hydrogen, with a molecular mass of ~28 amu, burns spontaneously when exposed to air, producing 0.063 g of B2O3. What are the empirical and molecular formulas of the compound?Sodium bicarbonate (baking soda), NaHCO3, can be purified by dissolving it in hot water (60 C), filtering to remove insoluble impurities, cooling to 0 C to precipitate solid NaHCO3, and then filtering to remove the solid, leaving soluble impurities in solution. Any NaHCO3 that remains in solution is not recovered. The solubility of NaHCO3 in hot water of 60 C is 164 g/L. Its solubility in cold water of 0 C is 69 g/L. What is the percent yield of NaHCO3 when ills purified by this method?What volume of 0.600 M HCl is required to react completely with 2.50 g of sodium hydrogen carbonate? NaHCO3(aq)+HCl(aq)NaCl2(g)+CO2(l)What volume of 0.08892 M HNO3 is required to react completely with 0.2352 g of potassium hydrogen phosphate? 2HNO2(aq)+K2HPO4(aq)H2PO4(aq)+2KNO3(aq)What volume of a 0.3300-M solution of sodium hydroxide would be required to titrate 15.00 mL of 0.1500 M oxalic acid? C2O4(aq)+2NaOH(aq)Na2C2O4(aq)+2H2O(l)What volume of a 0.00945-M solution of potassium hydroxide would be required to titrate 50.00 mL of a sample of acid rain with a H2SO4 concentration of 1.23104M. H2SO4(aq)+2KOH(aq)K2SO4(aq)+2H2O(l)A sample of solid calcium hydroxide, Ca(OH)2, is allowed to stand in water until a saturated solution is formed. A titration of 75.00 mL of this solution with 5.00102M HCl requires 36.6 mL of the acid to reach the end point. Ca(OH)2(aq)+2HCl(aq)CaCl2(aq)+2H2O(l) What is the molarity?What mass of Ca(OH)2 will react with 25.0 g of butanoic to form the preservative calcium butanoate according to the equation?How many milliliters of a 0.1500-M solution of KOH will be required to titrate 40.00 mL of a 0.0656-M solution of H3PO4? H3PO4(aq)+2KO(aq)K2HPO4(aq)+2(aq)+2H2O(l)Potassium acid phthalate, KNaC8H4O4, or KHP, is used in many laboratories, including general chemistry laboratories, to standardize solutions of base. KHP is one of only a few stable solid acids that can be dried by warming and weighed. A 0.3420-g sample of KNaC8H4O4 reacts with 35.73 mL of a NaOH solution in a titration. What is the molar concentration of the NaOH? KNaC8H4O4(aq)+NaOH(aq)KNaC8H4O4(aq)+H2O(aq)The reaction of WCl6 with Al at ~400 C gives black crystals of a compound containing only tungsten and chlorine. A sample of this compound, when reduced with hydrogen, gives 0.2232 g of tungsten metal and hydrogen chloride, which is absorbed in water. Titration of the hydrochloric acid thus produced requires 46.2 mL of 0.1051 M NaOH to reach the end point. What is the empirical formula of the black tungsten chloride?A burning match and a bonfire may have the same temperature, yet you would not sit around a burning match on a fall evening to stay warm. Why not?Prepare a table identifying several energy transitions that take place during the typical operation of an automobile.Explain the difference between heat capacity and specific heat of a substance.Calculate the heat capacity, in joules and in calories per degree, of the following: (a) 28.4 g of water (b) 1.00 oz of lead Calculate the heat capacity, in joules and in calories per degree, of the following: (a) 45.8 g of nitrogen gas (b) 1.00 pound of aluminum metal How much heat, in joules and in calories, must be added to a 75.0g iron block with a specific heat of 0.449 Jig C to increase its temperature from 25 C to its melting temperature of 1535 C?How much heat, in joules and in calories, is required to heat a 28.4-g (1-oz) ice cube from 23.0 C to 1.0 C?How much would the temperature of 275 g of water increase if 36.5 U of heat were added?If 14.5 kJ of heat were added to 485 g of liquid water, how much would its temperature increase?A piece of unknown substance weighs 44.7 g and requires 2110 J to increase its temperature from 23.2 °C to 89.6 °C. (a) What is the specific heat of the substance? (b) If it is one of the substances found in Table 5.1, what is its likely identity?A piece of unknown solid substance weighs 437.2 g, and requires 8460 J to increase its temperature from 19.3 °C to 68.9 °C. (a) What is the specific heat of the substance? (b) If it is one of the substances found in Table 5.1, what is its likely identity?An aluminum kettle weighs 1.05 kg. (a) What is the heat capacity of the kettle? (b) How much heat is required to increase the temperature of this kettle from 23.0 C to 99.0 C? (c) How much heat is required to heat this kettle from 23.0 C to 99.0 C if it contains 1.25 L of water (density of 0.997 g/mL and a specific heat of 4.184 J/g C)?Most people find waterbeds uncomfortable unless the water temperature is maintained at about 85 F. Unless it is heated, a waterbed that contains 892 L of water cools from 85 F to 72 F in 24 hours. Estimate the amount of electrical energy required over 24 hours, in kWh, to keep the bed from cooling. Note that 1 kilowatt-hour (kWh) = 3.6106 J, and assume that the density of water is 1.0 g/mL (independent of temperature). What other assumptions did you make? How did they affect your calculated result (i.e., were they likely to yield positive or negative errors)?A 500-mL bottle of water at room temperature and a 2-L bottle of water at the same temperature were placed in a refrigerator. After 30 minutes, the 500-mL bottle of water had cooled to the temperature of the refrigerator. An hour later, the 2-L of water had cooled to the same temperature. When asked which sample of water lost the most heat, one student replied that both bottles lost the same amount of heat because they started at the same temperature and finished at the same temperature. A second student thought that the 2-L bottle of water lost more heat because there was more water. A third student believed that the 500-mL bottle of water lost more heat because it cooled more quickly. A fourth student thought that it was not possible to tell because we do not know the initial temperature and the final temperature of the water. Indicate which of these answers is correct and describe the error in each of the other answers.Would the amount of heat measured for the reaction in Example 5.5 be greater, lesser, or remain the same if we used a calorimeter that was a poorer insulator than a coffee cup calorimeter? Explain your answer.Would the amount of heat absorbed by the dissolution in Example 5.6 appear greater, lesser, or remain the same if the experimenter used a calorimeter that was a poorer insulator than a coffee cup calorimeter? Explain your answer.Would the amount of heat absorbed by the dissolution in Example 5.6 appear greater, lesser, or remain the same if the heat capacity of the calorimeter were taken into account? Explain your answer.How many milliliters of water at 23 C with a density of 1.00 g/mL must be mixed with 180 mL (about 6 oz) of coffee at 95 C so that the resulting combination will have a temperature of 60 C? Assume that coffee and water have the same density and the same specific heat.How much will the temperature of a cup (180 g) of coffee at 95 C be reduced when a 45 g silver spoon (specific heat 0.24 J/g C) at 25 C is placed in the coffee and the two are allowed to reach the same temperature? Assume that the coffee has the same density and specific heat as water.A 45-g aluminum spoon (specific heat 0.88 J/g C) at 24 C is placed in 180 mL (180 g) of coffee at 85 C and the temperature of the two become equal. (a) What is the final temperature when the two become equal? Assume that coffee has the same specific heat as water. (b) The first time a student solved this problem she got an answer of 88 C. Explain why this is clearly an incorrect answer.The temperature of the cooling water as it leaves the hot engine of an automobile is 240 F. After it passes through the radiator it has a temperature of 175 F. Calculate the amount of heat transferred from the engine to the surroundings by one gallon of water with a specific heat of 4.184 J/g oC.A 70.0-g piece of metal at 80.0 °C is placed in loo g of water at 22.0 °C contained in a calorimeter like that shown in Figure 5.12. The metal and water come to the same temperature at 24.6 °C. How much heat did the metal give up to the water? What is the specific heat of the metal?If a reaction produces 1.506 kJ of heat, which is trapped in 30.0 g of water initially at 26.5 °C in a calorimeter like that in Figure 5.12, what is the resulting temperature of the water?A 0.500-g sample of KCl is added to 50.0 g of water in a calorimeter (Figure 5.12). If the temperature decreases by 1.05 °C, what is the approximate amount of heat involved in the dissolution of the KCl, assuming the specific heat of the resulting solution is 4.18 J/g °C? Is the reaction exothermic or endothermic?Dissolving 3.0 g of CaCl2(s) in 150.0 g of water in a calorimeter (Figure 5.12) at 22.4 °C causes the temperature to rise to 25.8 °C. What is the approximate amount of heat involved in the dissolution, assuming the specific heat of the resulting solution is 4.18 J/g °C? Is the reaction exothermic or endothermic?When 50.0 g of 0.200 M NaCl(aq) at 24.1 C is added to 100.0 g of 0.100 M AgNO3(aq) at 24.1 C in a calorimeter, the temperature increases to 25.2 C as AgCl(s) forms. Assuming the specific heat of the solution and products is 4.20 J/g C, calculate the approximate amount of heat in joules produced.The addition of 3.15 g of Ba(OH)28H2O to a solution of 1.52 g of NH4SCN in loo g of water in a calorimeter caused the temperature to fall by 3.1 C. Assuming the specific heat of the solution and products is 4.20 J/g C, calculate the approximate amount of heat absorbed by the reaction, which can be represented by the following equation: Ba(OH)28H2O(s)+2NH4SCN(aq)Ba(SCN)2(aq)+2NH3(aq)+10H2O(l)The reaction of 50 mL of acid and 50 mL of base described in Example 5.5 increased the temperature of the solution by 6.9 degrees C. How much would the temperature have increased if loo mL of acid and 100 mL of base had been used in the same calorimeter starting at the same temperature of 22.0 C? Explain your answer.If the 3.21 g of NH4NO3 in Example 5.6 were dissolved in 100.0 g of water under the same conditions, how much would the temperature change? Explain your answer.When 1.0 g of fructose, C6H12O6(s), a sugar commonly found in fruits, is burned in oxygen in a bomb calorimeter, the temperature of the calorimeter increases by 1.58 C. If the heat capacity of the calorimeter and its contents is 9.90 kJ/C, what is q for this combustion?When a 0.740-g sample of trinitrotoluene (TNT), C7H5N2O6, is burned in a bomb calorimeter, the temperature increases from 23.4 C to 26.9 C. The heat capacity of the calorimeter is 534 J/C, and it contains 675 mL of water. How much heat was produced by the combustion of the TNT sample?One method of generating electricity is by burning coal to heat water, which produces steam that drives an electric generator. To determine the rate at which coal is to be fed into the burner in this type of plant, the heat of combustion per ton of coal must be determined using a bomb calorimeter. When 1.00 g of coal is burned in a bomb calorimeter (Figure 5.17), the temperature increases by 1.48 °C. If the heat capacity of the calorimeter is 21.6 kJ/°C, determine the heat produced by combustion of a ton of coal ( 2.000103 pounds).The amount of fat recommended for someone with a daily diet of 2000 Calories is 65 g. What percent of the calories in this diet would be supplied by this amount of fat if the average number of Calories for fat is 9.1 Calories/g?A teaspoon of the carbohydrate sucrose (common sugar) contains 16 Calories (16 kcal). What is the mass of one teaspoon of sucrose if the average number of Calories for carbohydrates is 4.1 Calories/g?What is the maximum mass of carbohydrate in a 6-oz serving of diet soda that contains less than 1 Calorie per can if the average number of Calories for carbohydrates is 4.1 Calories/g?A pint of premium ice cream can contain 1100 Calories. What mass of fat, in grams and pounds, must be produced in the body to store an extra 1.1103 Calories if the average number of Calories for fat is 9.1 Calories/g?A serving of a breakfast cereal contains 3 g of protein, 18 g of carbohydrates, and 6 g of fat. What is the Calorie content of a serving of this cereal if the average number of Calories for fat is 9.1 Calories/g, for carbohydrates is 4.1 Calories/g, and for protein is 4.1 Calories/g?Which is the least expensive source of energy in kilojoules per dollar: a box of breakfast cereal that weighs 32 ounces and costs $4.23, or a liter of isooctane (density, 0.69 19 g/mL) that costs $0.45? Compare the nutritional value of the cereal with the heat produced by combustion of the isooctane under standard conditions. A 1.0-ounce serving of the cereal provides 130 Calories.Explain how the heat measured in Example 5.5 differs from the enthalpy change for the exothermic reaction described by the following equation: HCl(aq)+NaCl(aq)H2O(l)Using the data in the check your learning section of Example 5.5, calculate H in kJ/mol of AgNO3(aq) for the reaction: NaCl(aq)+AgNO3(aq)AgCl(s)+NaNO3(aq)Calculate the enthalpy of solution ( H for the dissolution) per mole of NH4NO3 under the conditions described in Example 5.6.Calculate H for the reaction described by the equation. (Hint : use the value for the approximate amount of heat absorbed by the reaction that you calculated in a previous exercise.) Ba(OH)28H2O(s)+2NH4(aq)Ba(SCN)2(aq)+2NH3(aq)+10H2O(l)Calculate the enthalpy of solution ( H for the dissolution) per mole of CaCl2 (refer to exercise 25).Although the gas used in an oxyacetylene torch (Figure 5.7) is essentially pure acetylene, the heat produced by combustion of one mole of acetylene in such a torch is likely not equal to the enthalpy of combustion of acetylene listed in Table 5.2. Considering the conditions for which the tabulated data are reported, suggest an explanation.How much heat is produced by burning 4.00 moles of acetylene under standard state conditions?How much heat is produced by combustion of 125 g of methanol under standard state conditions?How many moles of isooctane must be burned to produce loo U of heat under standard state conditions?What mass of carbon monoxide must be burned to produce 175 kJ of heat under standard state conditions?When 2.50 g of methane burns in oxygen, 125 kJ of heat is produced. What is the enthalpy of combustion per mole of methane under these conditions?How much heat is produced when loo mL of 0.250 M HCl (density, 1.00 g/mL) and 200 mL of 0.150 M NaOH (density, 1.00 g/mL) are mixed? HCl(aq)+NaO(aq)NaCl(aq)+H2O(l)H298=58kJ If both solutions are at the same temperature and the heat capacity of the products is 4.19 J/g C, how much will the temperature increase? What assumption did you make in your calculation?A sample of 0.562 g of carbon is burned in oxygen in a bomb calorimeter, producing carbon dioxide. Assume both the reactants and products are under standard state conditions, and that the heat released is directly proportional to the enthalpy of combustion of graphite. The temperature of the calorimeter increases from 26.74 C to 27.93 C. What is the heat capacity of the calorimeter and its contents?Before the introduction of chlorofluorocarbons, sulfur dioxide (enthalpy of vaporization, 6.00 kcal/mol) was used in household refrigerators. What mass of SO2 must be evaporated to remove as much heat as evaporation of 1.00 kg of CC12F2 (enthalpy of vaporization is 17.4 kJ/mol)? The vaporization reactions for SO2 and are SO2(l)SO2(g) and CCl2F(l)CCl2F2(g), respectively.Homes may be heated by pumping hot water through radiators. What mass of water will provide the same amount of heat when cooled from 95.0 to 35.0 C, as the heat provided when 100 g of steam is cooled from 110 C to 100 C.Which of the enthalpies of combustion in Table 5.2 the table are also standard enthalpies of formation?Does the standard enthalpy of formation of H2O(g) differ from H for the reaction 2H2(g)+O2(g)2H2O(g)?Joseph Priestly prepared oxygen in 1774 by heating red mercury(II) oxide with sunlight focused through a lens. How much heat is required to decompose exactly 1 mole of red HgO(s) to Hg(l) and O2(g) under standard conditions?How many kilojoules of heat will be released when exactly 1 mole of manganese, Mn, is burned to form Mn3O4(s) at standard state conditions?How many kilojoules of heat will be released when exactly 1 mole of iron, Fe, is burned to form Fe2O3(s) at standard state conditions?The following sequence of reactions occurs in the commercial production of aqueous nitric acid: 4NH3(g)+5O2(g)4NO(g)+6H2O(l)H=907kJ2NO(g)+O2(g)2NO2(g)H=113kJ3NO2+H2O(l)2HNO3(aq)+NO(g)H=139kJ Both graphite and diamond burn. C(s,graphite)+O2(g)CO2(g) For the conversion of graphite to diamond: C(s,diamond)C(s,diamond)H298=1.90kJ Which produces more heat, the combustion of graphite or the combustion of diamond?From the molar heats of formation in Appendix G, determine how much heat is required to evaporate one mole of water: H2O(l)H2O(g)Which produces more heat? Os(s)2O2(g)OsO4(s)orOs(s)2O2(g)OsO4(g) for the phase change OsO4(s)OsO4(g)H=56.4kJ Calculate H298 for the process Sb(s)+52Cl2(g)SbCl4(s) from the following information: Sb(s)+32Cl2(g)SbCl3(s)H298=314kJSbCl(s)+Cl2(g)SbCl5(g)H298=80kJ Calculate H298 for the process Zn(s)+S(s)+2O2(g)ZnSO4(s) from the following information: Zn(s)+S(s)ZnS(s)H298=206.0kJZnS(s)+2O2(g)ZnSO4(s)H298=776.8kJ Calculate H for the process Hg2Cl2(s)2Hg(l)+Cl2(g) from the following information: Hg(l)+Cl2(g)HgCl2(s)H=224kJHg(l)+HgCl2(s)HgCl2(s)H=41.2kJ Calculate H298 for the process Co3O4(s)3Co(s)+2O2(g) from the following information: Co(s)+12O2(g)CoO(s)H298=237.9kJ3CoO(s)+12O2(g)Co3O4(s)H298=177.5kJ Calculate the standard molar enthalpy of formation of NO(g) from the following data: N2(g)+2O22NO2(g)H298=66.4kJ2NO(g)+O22NO2(g)H298=114.1kJ Using the data in Appendix G, calculate the standard enthalpy change for each of the following reactions: (a) N2(g)+O2(g)2NO(g) (b) Si(s)+2Cl2(g)SiCl4(g) (c) Fe2O3(s)+3H2(g)2Fe(s)+3H2O(l) (d) 2LiOH(s)+CO2(g)Li2CO3(s)+H2O(g)Using the data in Appendix G, calculate the standard enthalpy change for each of the following reactions: (a) Si(s)+2F2(g)SiF4(g) (b) 2C(s)+2H2(g)+O2(g)CH3CO2H(l) (c) CH4(g)+N2(g)HCN(g)+NH3(g) ; (d) CS2(g)+3Cl2(g)CCl4(g)+S2Cl2(g)The following reactions can be used to prepare samples of metals. Determine the enthalpy change under standard state conditions for each. (a) 2Ag2O(s)4Ag(s)+O2(g) (b) SnO(s)+CO(g)Sn(s)+CO2(g) (c) Cr2O3(s)+3H2(g)2Cr(s)+3H2O(l) (d) 2Al(s)+Fe2O3(s)Al2O(s)+2Fe(s)The decomposition of hydrogen peroxide, H2O2, has been used to provide thrust in the control jets of various space vehicles. Using the data in Appendix G, determine how much heat is produced by the decomposition of exactly 1 mole of H2O2 under standard conditions. 2H2O2(l)2H2O(g)+O2(g)Calculate the enthalpy of combustion of propane, C3H8(g), for the formation of H2O(g) and CO2(g). The enthalpy of formation of propane is 104 kJ/mol.Calculate the enthalpy of combustion of butane, C4H10(g) for the formation of H2O(g) and CO2(g). The enthalpy of formation of butane is 126 kJ/mol.Both propane and butane are used as gaseous fuels. Which compound produces more heat per gram when burned?The white pigment TiO2 is prepared by the reaction of titanium tetrachioride, TiCl4, with water vapor in the gas phase: TiCl4(g)+2H2O(g)TiO2(s)+4HCl(g). How much heat is evolved in the production of exactly 1 mole of TiO2(s) under standard state conditions?Water gas, a mixture of H2 and CO, is an important industrial fuel produced by the reaction of steam with red hot coke, essentially pure carbon: C(s)+H2O(g)CO(g)+H2(g). (a) Assuming that coke has the same enthalpy of formation as graphite, calculate H298 for this reaction. (b) Methanol, a liquid fuel that could possibly replace gasoline, can be prepared from water gas and additional hydrogen at high temperature and pressure in the presence of a suitable catalyst: 2H2(g)+CO(g)CH2OH(g). Under the conditions of the reaction, methanol forms as a gas. Calculate for this reaction and for the condensation of gaseous methanol to liquid methanol. (c) Calculate the heat of combustion of 1 mole of liquid methanol to H2O(g) and CO2(g).In the early days of automobiles, illumination at night was provided by burning acetylene, C2H2. Though no longer used as auto headlamps, acetylene is still used as a source of light by some cave explorers. The acetylene is (was) prepared in the lamp by the reaction of water with calcium carbide, CaC2 : CaC2(s)+2H2O(l)Ca(OH)2(s)+C2H2(g). Calculate the standard enthalpy of the reaction. The Hf of CaC2 is 15.14 kcal/mol.From the data in Table 5.2, determine which of the following fuels produces the greatest amount of heat per gram when burned under standard conditions: CO(g) , CH4(g) , or C2H2(g) .The enthalpy of combustion of hard coal averages 35 kJ/g, that of gasoline, 1.28105 kJ/gal. How many kilograms of hard coal provide the same amount of heat as is available from 1.0 gallon of gasoline? Assume that the density of gasoline is 0.692 g/mL (the same as the density of isooctane).Ethanol, C2H5OH, is used as a fuel for motor vehicles, particularly in Brazil. (a) Write the balanced equation for the combustion of ethanol to CO2(g) and H2O(g), and, using the data in Appendix G, calculate the enthalpy of combustion of 1 mole of ethanol. (b) The density of ethanol is 0.7893 g/mL. Calculate the enthalpy of combustion of exactly 1 L of ethanol. (c) Assuming that an automobile’s mileage is directly proportional to the heat of combustion of the fuel, calculate how much farther an automobile could be expected to travel on 1 L of gasoline than on 1 L of ethanol. Assume that gasoline has the heat of combustion and the density of n—octane, C8H18(Hf=208.4kJ/mol;density=0.7025g/mL).Among the substances that react with oxygen and that have been considered as potential rocket fuels are diborane [ B2H6, produces B2O3(s) and H2O(g) ], methane [ CH4, produces CO2(g) and H2O(g) ], and hydrazine [ N2H2, produces N2(g) and H2O(g) ]. On the basis of the heat released by 1.00 g of each substance in its reaction with oxygen, which of these compounds offers the best possibility as a rocket fuel? The Hf of B2H6(g), CH4(g), and N2H4(l) may be found in Appendix G.How much heat is produced when 1.25 g of chromium meta’ reacts with oxygen gas under standard conditions?Ethylene, C2H2, a byproduct from the fractional distillation of petroleum, is fourth among the 50 chemical compounds produced commercially in the largest quantities. About 80% of synthetic ethanol is manufactured from ethylene by its reaction with water in the presence of a suitable catalyst. C2H2(g)+H2O(g)C2H5OH(l) Using the data in the table in Appendix G, calculate H for the reaction.The oxidation of the sugar glucose, C6H12O6, is described by the following equation: C6H12O6(s)+6CO2(g)+6H2O(l)H=2816kJ The metabolism of glucose gives the same products, although the glucose reacts with oxygen in a series of steps in the body. (a) How much heat in kilojoules can be produced by the metabolism of 1.0 g of glucose? (b) How many Calories can be produced by the metabolism of 1.0 g of glucose?Propane, C3H8, is a hydrocarbon that is commonly used as a fuel. (a) Write a balanced equation for the complete combustion of propane gas. (b) Calculate the volume of air at 25 C and 1.00 atmosphere that is needed to completely combust 25.0 grams of propane. Assume that air is 21.0 percent O2 by volume. (Hint: we will see how to do this calculation in a later chapter on gasesfor now use the information that 1.00 L of air at 25 C and 1.00 atm contains 0.275 g of 2 per liter.) (c) The heat of combustion of propane is 2,219.2 kJ/mol. Calculate the heat of formation, Hf of propane given that Hf of H2O(l)=285.8 kJ/mol and Hf of CO2(g)=393.5 kJ/mol. (d) Assuming that all of the heat released in burning 25.0 grams of propane is transferred to 4.00 kilograms of water, calculate the increase in temperature of the water.During a recent winter month in Sheboygan, Wisconsin, it was necessary to obtain 3500 kWh of heat provided by a natural gas furnace with 89% efficiency to keep a small house warm (the efficiency of a gas furnace is the percent of the heat produced by combustion that is transferred into the house). (a) Assume that natural gas is pure methane and determine the volume of natural gas in cubic feet that was required to heat the house. The average temperature of the natural gas was 56 F; at this temperature and a pressure of 1 atm, natural gas has a density of 0.68 1 g/L. (b) How many gallons of LPG (liquefied petroleum gas) would be required to replace the natural gas used? Assume the LPG is liquid propane [ C3H8 : density, 0.5318 g/mL; enthalpy of combustion, 2219 Id/mo for the formation of CO2(g) and H2O(l) ] and the furnace used to burn the LPG has the same efficiency as the gas furnace. (c) What mass of carbon dioxide is produced by combustion of the methane used to heat the house? (d) What mass of water is produced by combustion of the methane used to heat the house? (e) What volume of air is required to provide the oxygen for the combustion of the methane used to heat the house? Air contains 23% oxygen by mass. The average density of air during the month was 1.22 g/L. (f) How many kilowatt—hours ( 1kWh=3.6106 J) of electricity would be required to provide the heat necessary to heat the house? Note electricity is 100% efficient in producing heat inside a house. (g) Although electricity is 100% efficient in producing heat inside a house, production and distribution of electricity is not 100% efficient. The efficiency of production and distribution of electricity produced in a coal-fired power plant is about 40%. A certain type of coal provides 2.26 kWh per pound upon combustion. What mass of this coal in kilograms will be required to produce the electrical energy necessary to heat the house if the efficiency of generation and distribution is 40%?The light produced by a red neon sign is due to the emission of light by excited neon atoms. Qualitatively describe the spectrum produced by passing light from a neon lamp through a prism.An FM radio station found at 103.1 on the FM dial broadcasts at a frequency of 1.031188s1 (103.1 MHz). What is the wavelength of these radio waves in meters?FM-95, an FM radio station, broadcasts at a frequency of 9.51107s1 s (95.1 MHz). What is the wavelength of these radio waves in meters?A bright violet line occurs at 435.8 nm in the emission spectrum of mercury vapor. What amount of energy, in joules, must be released by an electron in a mercury atom to produce a photon of this light?Light with a wavelength of 614.5 nm looks orange. What is the energy, in joules, per photon of this orange light? What is the energy in eV(1eV=1.6021019J)?Heated lithium atoms emit photons of light with an energy of 2.9611019 J. Calculate the frequency and wavelength of one of these photons. What is the total energy in 1 mole of these photons? What is the color of the emitted light?A photon of light produced by a surgical laser has an energy of 3.0271019 J. Calculate the frequency and wavelength of the photon. What is the total energy in 1 mole of photons? What is the color of the emitted light?When rubidium ions are heated to a high temperature, two lines are observed in its line spectrum at wavelengths (a) 7.9107 m and (b) 402107 m. What are the frequencies of the two lines? What color do we see when we heat a rubidium compound?The emission spectrum of cesium contains two lines whose frequencies are (a) 3.451014 Hz and (b) 6.531014 Hz. What are the wavelengths and energies per photon of the two lines? What color are the lines?Photons of infrared radiation are responsible for much of the warmth we feel when holding our hands before a fire. These photons will also warm other objects. How many infrared photons with a wavelength of 1.5106 m must be absorbed by the water to warm a cup of water (175 g) from 25.0 C to 40 C?One of the radiographic devices used in a dentist’s office emits an X-ray of wavelength 2.0901011 m. What is the energy, in joules, and frequency of this X-ray?The eyes of certain reptiles pass a single visual signal to the brain when the visual receptors are struck by photons of a wavelength of 850 nm. If a total energy of 3.151014 J is required to trip the signal, what is the minimum number of photons that must strike the receptor?RGB color television and computer displays use cathode ray tubes that produce colors by mixing red, green, and blue light. If we look at the screen with a magnifying glass, we can see individual dots turn on and off as the colors change. Using a spectrum of visible light, determine the approximate wavelength of each of these colors. What is the frequency and energy of a photon of each of these colors?Answer the following questions about a Blu-ray laser: (a) The laser on a Blu-ray player has a wavelength of 405 nm. In what region of the electromagnetic spectrum is this radiation? What is its frequency? (b) A Blu-ray laser has a power of 5 millwatts (1watt=1Js1). How many photons of light are produced by the laser in 1 hour? (c) The ideal resolution of a player using a laser (such as a Blu-ray player), which determines how close together data can be stored on a compact disk, is determined using the following formula: Resolution =0.60(/NA), where A is the wavelength of the laser and NA is the numerical aperture. Numerical aperture is a measure of the size of the spot of light on the disk; the larger the NA, the smaller the spot. In a typical Blu-ray system, NA = 0.95. If the 405-nm laser is used in a Blu-ray player, what is the closest that information can be stored on a Blu-ray disk? (d) The data density of a Blu-ray disk using a 405-nm laser is 1.5107 bits mm2. Disks have an outside diameter of 120 mm and a hole of 15-mm diameter. How many data bits can be contained on the disk? If a Blu-ray disk can hold 9,400,000 pages of text, how many data bits are needed for a typed page? (Hint: Determine the area of the disk that is available to hold data. The area inside a circle is given by A=r2, where the radius r is one-half of the diameter.)What is the threshold frequency for sodium metal if a photon with frequency 6.661014s1 ejects an electron with 7.741020 J kinetic energy? Will the photoelectric effect be observed if sodium is exposed to orange light?Why is the electron in a Bohr hydrogen atom bound less tightly when it has a quantum number of 3 than when it has a quantum number of 1?What does it mean to say that the energy of the electrons in an atom is quantized?Using the Bohr model, determine the energy, in joules, necessary to ionize a ground-state hydrogen atom. Show your calculations.The electron volt (eV) is a convenient unit of energy for expressing atomic-scale energies. It is the amount of energy that an electron gains when subjected to a potential of 1 volt; 1eV=1.6021019 J. Using the Bohr model, determine the energy, in electron volts, of the photon produced when an electron in a hydrogen atom moves from the orbit with n=5 to the orbit with n=2. Show your calculations.Using the Bohr model, determine the lowest possible energy, in joules, for the electron in the Li2+ ion.Using the Bohr model, determine the lowest possible energy for the electron in the He+ ion.Using the Bohr model, determine the energy of an electron with n=6 in a hydrogen atom.Using the Bohr model, determine the energy of an electron with n=8 in a hydrogen atom.How far from the nucleus in angstroms (1 angstrom =11010 m) is the electron in a hydrogen atom if it has an energy of 8.721020 J?What is the radius, in angstroms, of the orbital of an electron with n = 8 in a hydrogen atom?Using the Bohr model, determine the energy in joules of the photon produced when an electron in a He+ ion moves from the orbit with n = 5 to the orbit with n = 2.Using the Bohr model, determine the energy in joules of the photon produced when an electron in a L2+ ion moves from the orbit with n = 2 to the orbit with n = 1.Consider a large number of hydrogen atoms with electrons randomly distributed in the n = 1, 2, 3, and 4 orbits. (a) How many different wavelengths of light are emitted by these atoms as the electrons fall into lower-energy orbitals? (b) Calculate the lowest and highest energies of light produced by the transitions described in part (a). (c) Calculate the frequencies and wavelengths of the light produced by the transitions described in part (b).How are the Bohr model and the Rutherford model of the atom similar? How are they different?The spectra of hydrogen and of calcium are shown in Figure 6.13. What causes the lines in these spectra? Why are the colors of the lines different? Suggest a reason for the observation that the spectrum of calcium is more complicated than the spectrum of hydrogen.How are the Bohr model and the quantum mechanical model of the hydrogen atom similar? How are they different?What are the allowed values for each of the four quantum numbers: n, l, ml, and ms?Describe the properties of an electron associated with each of the following four quantum numbers: n,l,ml, and ms.Answer the following questions: (a) Without using quantum numbers, describe the differences between the shells, subshells, and orbitals of an atom. (b) How do the quantum numbers of the shells, subshells, and orbitals of an atom differ?Identify the subshell in which electrons with the following quantum numbers are found: (a) n=2,l=1 (b) n=4,l=2 (c) n=6,l=0 Which of the subshells described in the previous question contain degenerate orbitals? How many degenerate orbitals are in each?Identify the subshell in which electrons with the following quantum numbers are found: (a) n=3,l=2 (b) n=1,l=0 (c) n=4,l=3 Which of the subshells described in the previous question contain degenerate orbitals? How many degenerate orbitals are in each?Sketch the boundary surface of a dx2y2 and a py orbital. Be sure to show and label the axes.Sketch the px and dxz orbitals. Be sure to show and label the coordinates.Consider the orbitals shown here in outline. (a) What is the maximum number of electrons contained in an orbital of type (x)? Of type (y)? Of type (z)? (b) How many orbitals of type (x) are found in a shell with n=2? How many of type (y)? How many of type (z)? (c) Write a set of quantum numbers for an electron in an orbital of type (x) in a shell with n=4, of an orbital of type (y) in a shell with n=2. Of an orbital of type (z) in a shell with n=3. (d) What is the smallest possible n value for an orbital of type (x)? Of type (y)? Of type (z)? (e) What are the possible I and ml values for an orbital of type (x)? Of type (y)? Of type (z)?State the Heisenberg uncertainty principle. Describe briefly what the principle implies.How many electrons could be held in the second shell of an atom if the spin quantum number ms could have three values instead of just two? (Hint: Consider the Pauli exclusion principle.)Which of the following equations describe particle-like behavior? Which describe wavelike behavior? Do any involve both types of behavior? Describe the reasons for your choices. (a) c=v (b) E=mv22 (c) r=n2a0Z (d) E=hv (e) =hmv Write a set of quantum numbers for each of the electrons with an n of 4 in a Se atom.Read the labels of several commercial products and identify monatomic ions of at least four transition elements contained in the products. Write the complete electron configurations of these cations.Read the labels of several commercial products and identify monatomic ions of at least six main group elements contained in the products. Write the complete electron configurations of these cations and anions.Using complete subshell notation (not abbreviations, 1s22s22p6, and so forth), predict the electron configuration of each of the following atoms: (a)C (b)P (c)V (d) Sb (e) Sm Using complete subshell notation ( 1s22s22p6, and so forth), predict the electron configuration of each of the following atoms: (a)N (b) Si (c) Fe (d) Te (e) Tb Is 1s22s22p6 the symbol for a macroscopic property or a microscopic property of an element? Explain your answer.What additional information do we need to answer the question Which ion has the electron configuration 1s22s22p63s23p6 ?Draw the orbital diagram for the valence shell of each of the following atoms (a) C (b) P (c) V (d) Sb (e) Ru Use an orbital diagram to describe the electron configuration of the valence shell of each of the following atoms: (a)N (b) Si (c) Fe (d) Te (e) Mo Using complete subshell notation ( 1s22s22p6, and so forth), predict the electron configurations of the following ions. (a) N3- (b) Ca2+ (c) S- (d) Cs2+ (e) Cr2+ (f)Gd3+Which atom has the electron configuration 1s22s22p63s23p64s23d104p65s24d2?Which atom has the electron configuration 1s22s22p63s23p63d74s2?Which ion with a +1 charge has the electron configuration 1s22s22p63s23p63d104s24p6? Which ion with a —2 charge has this configuration?Which of the following atoms contains only three valence electrons: Li, B, N, F, Ne?Which of the following has two unpaired electrons? (a) Mg (b) Si (c)S (d) Both Mg and S (e) Both Si and S.Which atom would be expected to have a half-filled 6p subshell?Which atom would be expected to have a half-filled 4s subshell?In one area of Australia, the cattle did not thrive despite the presence of suitable forage. An investigation showed the cause to be the absence of sufficient cobalt in the soil. Cobalt forms cations in two oxidation states, Co2 and Co3+. Write the electron structure of the two cations.Thallium was used as a poison in the Agatha Christie mystery story The Pale Horse. Thallium has two possible cationic forms, +1 and +3. The +1 compounds are the more stable. Write the electron structure of the +1 cation of thallium.Write the electron configurations for the following atoms or ions: (a) B3+ (b) O (c) Cl3+ (d) Ca2+ (e) Ti Cobalt60 and iodine131 are radioactive isotopes commonly used in nuclear medicine. How many protons, neutrons, and electrons are in atoms of these isotopes? Write the complete electron configuration for each isotope.Write a set of quantum numbers for each of the electrons with an n of 3 in a Sc atom.Based on their positions in the periodic table, predict which has the smallest atomic radius: Mg, Sr, Si, Cl, I.Based on their positions in the periodic table, predict which has the largest atomic radius: Li, Rb, N, F, I.Based on their positions in the periodic table, predict which has the largest first ionization energy: Mg, Ba, B, O, Te.Based on their positions in the periodic table, predict which has the smallest first ionization energy: Li, Cs, N, I.Based on their positions in the periodic table, rank the following atoms in order of increasing first ionization energy: F, Li, N, Rb Based on their positions in the periodic table, rank the following atoms in order of increasing first ionization energy: Mg, O, S, Si Atoms of which group in the periodic table have a valence shell electron configuration of ns2np2?Atoms of which group in the periodic table have a valence shell electron configuration of ns2?Based on their positions in the periodic table, list the following atoms in order of increasing radius: Mg. Ca, Rb, Cs.Based on their positions in the periodic table, list the following atoms in order of increasing radius: Sr, Ca, Si, Cl.Based on their positions in the periodic table, list the following ions in order of increasing radius: K+, Ca2+, Al3+, Si4+.List the following ions in order of increasing radius: Li+,Mg2+,Br,Te2.Which atom and/or ion is (are) isoelectronic with Br+:Se2+,Se,As,Kr,Ga3+,Cl?Which of the following atoms and ions is (are) isoelectronic with S2+:Si4+,Ar,As3+,Si,Al3+?Compare both the numbers of protons and electrons present in each to rank the following ions in order of increasing radius: As3,Br,K+,Mg2+.Of the five elements Al, Cl, I, Na, Rb, which has the most exothermic reaction? (E represents an atom.) What name is given to the energy for the reaction? Hint: note the process depicted does not correspond to electron affinity E+(g)+eE(g)Of the five elements Sn, Si, Sb, O, Te, which has the most endothermic reaction? (E represents an atom.) What name is given to the energy for the reaction? E(g)E+(g)+e The ionic radii of the ions S2, Cl, and K+ are 184, 181, 138 pm respectively. Explain why these ions have different sizes even though they contain the same number of electrons.Which main group atom would be expected to have the lowest second ionization energy?Explain why Al is a member of group 13 rather than group 3?Does a cation gain protons to form a positive charge or does it lose electrons?Iron(III) sulfate [Fe2( SO 4)3] is composed of Fe3+ and SO42 ions. Explain why a sample of iron(III) sulfate is uncharged.Which of the following atoms would be expected to form negative ions in binary ionic compounds and which would be expected to form positive ions: P, I, Mg, Cl, In, Cs, O, Pb, Co?Which of the following atoms would be expected to form negative ions in binary ionic compounds and which would be expected to form positive ions: Br, Ca, Na, N, F, Al, Sn, S, Cd?Predict the charge on the monatomic ions formed from the following atoms in binary ionic compounds: (a) P (b) Mg (c) Al (d) O (e) Cl (f) Cs Predict the charge on the monatomic ions formed from the following atoms in binary ionic compounds: (a) I (b) Sr (c) K (d) N (e) S (f) In Write the electron configuration for each of the following ions: (a) As3 (b) I (c) Be2+ (d) Cd2+ (e) O2 (f) Ga3+ (g) Li+ (h) N3 (j) Sn2+ (j) Co2+ (k) Fe2+ (1) As3+Write the electron configuration for the monatomic ions formed from the following elements (which form the greatest concentration of monatomic ions in seawater): (a) Cl (b) Na (c) Mg (d) Ca (e) K (f) Br (g) Sr (h) F Write out the full electron configuration for each of the following atoms and for the monatomic ion found in binary ionic compounds containing the element: (a) AI (b) Br (c) Sr (d) Li (e) As (f) S From the labels of several commercial products, prepare a list of six ionic compounds in the products. For each compound, write the formula. (You may need to look up some formulas in a suitable reference.)Why is it incorrect to speak of a molecule of solid NaCl?What information can you use to predict whether a bond between two atoms is covalent or ionic?Predict which of the following compounds are ionic and which are covalent, based on the location of their constituent atoms in the periodic table: (a) CI2CO (b) MnO (c) Nd3 (d) CoBr2 (e) K2S (f) CO (g) CaF2 (h) HI (j) CaO (j) IBr (k) CO2 Explain the difference between a nonpolar covalent bond, a polar covalent bond, and an ionic bond.From its position in the periodic table, determine which atom in each pair is more electronegative: (a) Br or Cl (b) N or O (c) S or O (d) P or S (e) Si or N (f) Ba or P (g) N or K From its position in the periodic table, determine which atom in each pair is more electronegative: (a) N or P (b) N or Ge (c) S or F (d) Cl or S (e) H or C (f) Se or P (g) C or Si From their positions in the periodic able, arrange the atoms in each of the following series in order of increasing electronegativity: (a) C, F, H, N. O (b) Br. Cl, F, H, I (c) F. H, O. P. S (d) AI, H. Na, O. P (e) Ba. H, N, O, As From their positions in the periodic table, arrange the atoms in each of the following series in order of increasing electronegativity: (a) As, H, N, P, Sb (b) Cl, H, P, S, Si (c) Br, Cl, Ge, H, Sr (d) Ca, H, K, N, Si (e) Cl, Cs, Ge, H, Sr Which atoms can bond to sulfur so as to produce a positive partial charge on the sulfur atom?Which is the most polar bond? (a) CC (b) CH (c) NH (d) OH (e) Se-H Identify the more polar bond in each of the following pairs of bonds: (a) HF or HCl (b) NO or CO (c)SHorOH (d) PC1l or SCl (e) CH or NH (f) SO or PO (g) CN or NN Which of the following molecules or ions contain polar bonds? (a) O3 (b) S8 (c) O22 (d) NO3 (e) CO2 (f) H2S (g) BH4 Write the Lewis symbols for each of the following ions: (a) As3 (b) I (c) Be2+ (d) O2 (e) Ga3+ (f) Li+ (g) N3 Many monatomic ions are found in seawater, including the ions formed from the following list of elements. Write the Lewis symbols for the monatomic ions formed from the following elements: (a) Cl (b) Na (c) Mg (d) Ca (e) K (f) Br (g) Sr (h) F Write the Lewis symbols of the ions in each of the following ionic compounds and the Lewis symbols of the atom from which they are formed: (a) MgS (b) Al2O3 (c) GaCl3 (d) K2O (e) Li3N (f) KF Iii (he Lewis structures listed here, M and X represent various elements iii the third period of the periodic table. Write the formula of each compound using the chemical symbols of each element: (a) (b) (c) (d)Write the Lewis structure for the diatomic molecule P2, an unstable form of phosphorus found in high temperature phosphorus vapor.Write Lewis structures for the following: (a) H2 (b) HBr (c) PCl3 (d) SF2 (e) H2CCH2 (f) HNNH (g) H2CNH (h) NO (i) N2 (j) CO (k) CN Write Lewis structures for the following: (a) O2 (b) H2CO (c) AsF3 (d) ClNO (e) SiCl4 (f) H3O+ (g) NH4+ (h) BF4 (i) HCCH (j) ClCN (k) C22+Write Lewis structures for the following: (a) ClF3 (b) PCl5 (c) BF3 (d) PF6 Write Lewis structures for the following: (a) SeF6 (b) XeF4 (c) SeCl3+Write Lewis structures for: (a) PO43 (b) ICl4 (c) SO32 (d) HONO Correct the following statement: The bonds in solid PbCl2 are ionic; the bond in a HCl molecule is covalent. Thus, all of the valence electrons in PbCl2 are located on the Cl ions, and all of the valence electrons in a HCl molecule are shared between the H and Cl atoms.Write Lewis structures for the following molecules or ions: (a) SbH3 (b) XeF2 (c) Se8 (a cyclic molecule with a ring of eight Se atoms)Methanol, H3COH, is used as the fuel in some race cars. Ethanol, C2H5OH, is used extensively as motor fuel in Brazil. Both methanol and ethanol produce CO2 and H2O when they burn. Write the chemical equations for these combustion reactions using Lewis structures instead of chemical formulas.Many planets in our solar system contain organic chemicals including methane (CH4) and traces of ethylene (C2H4), ethane (C2H6), propyne (H3CCCH), and diacetylene (HCCCCH). Write the Lewis structures for each of these molecules.Carbon tetrachloride was formerly used in fire extinguishers for electrical fires. It is no longer used for this purpose because of the formation of the toxic gas phosgene, Cl2CO. Write the Lewis structures for carbon tetrachloride and phosgene.Identify the atoms that correspond to each of the following electron configurations. Then, write the Lewis symbol for the common ion formed from each atom: (a) 1s22s22p5 (b) 1s22s22p63s2 (c) 1s22s22p63s23p64s23d10 (d) 1s22s22p63s23p64s23d104p4 (e) 1s22s22p63s23p64s23d104p1 The arrangement of atoms in several biologically important molecules is given here. Complete the Lewis structures of these molecules by adding multiple bonds and lone pairs. Do not add any more atoms. (a) the amino acid serine: (b) urea: (c) pyruvic acid: (d) uracil: (e) carbonic acid:A compound with a molar mass of about 28 g/mol contains 85.7% carbon and 14.3% hydrogen by mass. Write the Lewis structure for a molecule of the compound.A compound with a molar mass of about 42 g/mol contains 85.7% carbon and 14.3% hydrogen by mass. Write the Lewis structure for a molecule of the compound.Two arrangements of atoms are possible for a compound with a molar mass of about 45 g/mol that contains 52.2% C, 13.1% H, and 34.7% 0 by mass. Write the Lewis structures for the two molecules.How are single, double, and triple bonds similar? How do they differ?Write resonance forms that describe the distribution of electrons in each of these molecules or ions. (a) selenium dioxide, OSeO (b) nitrate ion, NO3 (c) nitric acid, HNO3 (N is bonded to an OH group and two O atoms) (d) benzene, C6H6 : (e) the formate ion:Write resonance forms that describe the distribution of electrons in each of these molecules or ions. (a) sulfur dioxide, SO2 (b) carbonate ion, CO32 (c) hydrogen carbonate ion. HCO3 (C is bonded to an OH group and two O atoms) (d) pyridine: (e) the allyl ion:Write the resonance forms of ozone, Q3, the component of the upper atmosphere that protects the Earth from ultraviolet radiation.Sodium nitrite, which has been used to preserve bacon and other meats, is an ionic compound. Write the resonance forms of the nitrite ion, NO2.In terms of the bonds present, explain why acetic acid, CH3CO2H, contains two distinct types of carbon-oxygen bonds, whereas the acetate ion, formed by loss of a hydrogen ion from acetic acid, only contains one type of carbon oxygen bond. The skeleton structures of these species are shown:Write the Lewis structures for the following, and include resonance structures where appropriate. Indicate which has the strongest carbon-oxygen bond. (a) CO2 (b) CO Toothpastes containing sodium hydrogen carbonate (sodium bicarbonate) and hydrogen peroxide are widely used. Write Lewis structures for the hydrogen carbonate ion and hydrogen peroxide molecule, with resonance forms where appropriate.Determine the formal charge of each element in the following: (a) HCl (b) CF4 (c) PCl3 (d) PF5 Determine the formal charge of each element in the following: (a) H3O+ (b) SO42 (c) NH3 (d) O22 (e) H2O2 Calculate the formal charge of chlorine in the molecules Cl2, BeCl2, and ClF5.54. Calculate the formal charge of each element in the following compounds and ions: (a) F2CO (b) NO (c) BF4 (d) SnCl3 (e) H2CCH2 (f) CIF3 (g) SeF6 (h) PO43 Draw all possible resonance structures for each of these compounds. Determine the formal charge on each atom in each of the resonance structures: (a) O3 (b) SO2 (c) NO2 , (d) NO3 Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in nitrosyl chloride: ClNO or ClON?Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in hypochlorous acid: HOCl or OClH?Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in sulfur dioxide: OSO or SOO?Draw the structure of hydroxylamine, H3NO, and assign formal charges; look up the structure. Is the actual structure consistent with the formal charges?Iodine forms a series of fluorides (listed here). Write Lewis structures for each of the four compounds and determine the formal charge of the iodine atom in each molecule: (a) IF (b) IF3 (c) IF5 (d) IF7 Write the Lewis structure and chemical formula of the compound with a molar mass of about 70 g/mol that contains 19.7% nitrogen and 80.3% fluorine by mass, and determine the formal charge of the atoms in this compound.Which of the following structures would we expect for nitrous acid? Determine the formal charges:Sulfuric acid is the industrial chemical produced in greatest quantity worldwide. About 90 billion pounds are produced each year in the United States alone. Write the Lewis structure for sulfuric acid, H2SO4, which has two oxygen atoms and two OH groups bonded to the sulfur.Which bond in each of the following pairs of bonds is the strongest? (a) CCorC=C (b) CNorCN (c) COorC=O (d) HForH=Cl (e) CHorOH (f) CNorCO Using the bond energies in Table 7.2, determine the approximate enthalpy change for each of the following reactions: (a) H2(g)+Br2(g)2HBr(g) (b) CH4(g)+I2(g)CH3I(g)+HI(g) (c) C2H4(g)+3O2(g)2CO2(g)+2H2O(g)Using the bond energies in Table 7.2, determine the approximate enthalpy change for each of the following reactions: (a) Cl2(g)+3F2(g)2ClF3(g) (b) H2C=CH2(g)+H2(g)H3CCH3(g) (c) 2C2H6(g)+7O2(g)4CO2(g)+6H2O(g) .When a molecule can form two different structures, the structure with the stronger bonds is usually the more stable form. Use bond energies to predict the correct structure of the hydroxylamine molecule:How does the bond energy of HCl(g) differ from the standard enthalpy of formation of HCl(g)?Using the standard enthalpy of formation data in Appendix G, show how the standard enthalpy of formation of HCl(g) can be used to determine the bond energy.Using the standard enthalpy of formation data in Appendix G, calculate the bond energy of the carbon-sulfur double bond in CS2.Using the standard enthalpy of formation data in Appendix G, determine which bond is stronger: the SF bond in SF4(g) or in SF6(g)?Using the standard enthalpy of formation data in Appendix G. determine which bond is stronger: the PCl bond in PCl3(g) or in PCl5(g)?Complete the following Lewis structure by adding bonds (not atoms), and then indicate the longest bond:Use the bond energy to calculate an approximate value of H for the following reaction. Which is the more stable form of FNO2?Element First Ionization Energy (kJImol) Second Ionization Energy (kiImol) I K 419 3050 Ca 590 1140 75. Use principles of atomic structure to answer each of the following: (a) The radius of the Ca atom is 197 pm; the radius of the Ca2+ ion is 99 pm. Account for the difference. (b) The lattice energy of CaO(s) is 3460 kJ/mol; the lattice energy of K2O is 2240 kJ/mol. Account for the difference. (c) Given these ionization values, explain the difference between Ca and K with regard to their first and second ionization energies. Element First Ionization Energy (kJ/mol) Second Ionization Energy (kJ/mol) K 419 3050 Ca 590 1140 (d) The first ionization energy of Mg is 738 kJ/mol and that of Al is 578 kJ/mol. Account for this difference.The lattice energy of LiF is 1023 kJ/mol, and the Li—F distance is 200.8 pm. NaF crystallizes in the same structure as LiF but with a Na—F distance of 231 pm. Which of the following values most closely approximates the lattice energy of NaF: 510, 890, 1023, 1175, or 4090 kJ/mol? Explain your choice.For which of the following substances is the least energy required to convert one mole of the solid into separate ions? (a) MgO (b) SrO (c) KF (d) CsF (e) MgF2 The reaction of a metal, M, with a halogen, X2, proceeds by an exothermic reaction as indicated by this equation: M(s)+X2(g)MX2(s). For each of the following, indicate which option will make the reaction more exothermic. Explain your answers. (a) a large radius vs. a small radius for M+2 (b) a high ionization energy vs. a low ionization energy for M (c) an increasing bond energy for the halogen (d) a decreasing electron affinity for the halogen (e) an increasing size of the anion formed by the halogen The lattice energy of LiF is 1023 kJ/mol, and the LiF distance is 201 pm. MgO crystallizes in the same structure as LiF but with a Mg—O distance of 205 pm. Which of the following values most closely approximates the lattice energy of MgO: 256 kJ/mol, 512 kJ/mol, 1023 kJ/mol, 2046 kJ/mol, or 4008 kJ/mol? Explain your choice.Which compound in each of the following pairs has the larger lattice energy? Note: Mg2+ and Li+ have similar radii; O2 and F have similar radii. Explain your choices. (a) MgOorMgSe (b) LiForMgO (c) Li2OorLiCl (d) Li2SeorMgO Which compound in each of the following pairs has the larger lattice energy? Note: Ba2+ and K+ have similar radii; S2 and Cl have similar radii. Explain your choices. (a) K2OorNa2O (b) K2SorBa2S (c) KClorBaS (d) BaSorBaCl2 Which of the following compounds requires the most energy to convert one mole of the solid into separate ions? (a) MgO (b) SrO (c) KF (d) CsF (e) MgF2 Which of the following compounds requires the most energy to convert one mole of the solid into separate ions? (a) K2S (b) K2O (c) CaS (d) Cs2S (e) CaO The lattice energy of KF is 794 kJ/mol, and the interionic distance is 269 pm. The Na—F distance in NaF, which has the same structure as KF, is 231 pm. Which of the following values is the closest approximation of the lattice energy of NaF: 682 kJ/mol, 794 kJ/mol, 924 kJ/mol, 1588 kJ/mol, or 3175 kJ/mol? Explain your answer.Explain why the HOH molecule is bent, whereas the HBeH molecule is linear.What feature of a Lewis structure can be used to tell if a molecule’s (or ion’s) electron-pair geometry and molecular structure will be identical?Explain the difference between electron-pair geometry and molecular structure.Why is the HNH angle in NH3 smaller than the HCH bond angle in CH4? Why is the HNH angle in NH4+ identical to the HCH bond angle in CH4?Explain how a molecule that contains polar bonds can be nonpolar.As a general rule, MX molecules (where M represents a central atom and X represents terminal atoms; n = 2 5) are polar if there is one or more lone pairs of electrons on M. NH3 (M = N, X = H, n = 3) is an example. There are two molecular structures with lone pairs that are exceptions to this rule. What are they?Predict the electron pair geometry and the molecular structure of each of the following molecules or ions: (a) SF6 (b) PCl5 (c) BeH2 (d) CH3+Identify the electron pair geometry and the molecular structure of each of the following molecules or ions: (a) IF6+ (b) CF4 (c) BF3 (d) SiF5 (e) BeCl2 What are the electron-pair geometry and the molecular structure of each of the following molecules or ions? (a) CIF5 (b) CIO2 (c) TeCl42 (d) PCl3 (e) SeF4 (f) PH2

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