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Introductory Chemistry: An Active Learning Approach
- A rebreathing gas mask contains potassium superoxide, KO2, which reacts with moisture in the breath to give oxygen. 4KO2(s)+2H2O(l)4KOH(s)+3O2(g) Estimate the grams of potassium superoxide required to supply a persons oxygen needs for one hour. Assume a person requires 1.00 102 kcal of energy for this time period. Further assume that this energy can be equated to the heat of combustion of a quantity of glucose, C6H12O6, to CO2(g) and H2O(l). From the amount of glucose required to give 1.00 102 kcal of heat, calculate the amount of oxygen consumed and hence the amount of KO2 required. The ff0 for glucose(s) is 1273 kJ/mol.arrow_forwardEthanol, C2H5OH, is a gasoline additive that can be produced by fermentation of glucose. C6H12O62C2H5OH+2CO2 (a) Calculate the mass (g) of ethanol produced by the fermentation of 1.000 lb glucose. (b) Gasohol is a mixture of 10.00 mL ethanol per 90.00 mL gasoline. Calculate the mass (in g) of glucose required to produce the ethanol in 1.00 gal gasohol. Density of ethanol = 0.785 g/mL. (c) By 2022, the U. S. Energy Independence and Security Act calls for annual production of 3.6 1010 gal of ethanol, no more than 40% of it produced by fermentation of corn. Fermentation of 1 ton (2.2 103 lb) of corn yields approximately 106 gal of ethanol. The average corn yield in the United States is about 2.1 105 lb per 1.0 105 m2. Calculate the acreage (in m2) required to raise corn solely for ethanol production in 2022 in the United States.arrow_forwardWhen one mole of ethylene gas, C2H4, reacts with fluorine gas, hydrogen fluoride and carbon tetrafluoride gases are formed and 2496.7 kJ of heat are given off. What is Hf for CF4(g)?arrow_forward
- The equation for the fermentation of glucose to alcohol and carbon dioxide is: C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g) The enthalpy change for the reaction is 67 kJ. Is this reaction exothermic or endothermic? Is energy, in the form of heat, absorbed or evolved as the reaction occurs?arrow_forwardNitrogen monoxide, a gas recently found to be involved in a wide range of biological processes, reacts with oxygen to give brown NO2 gas. 2 NO(g) + O2(g) NO2(g)rH = 114.1 kJ/mol-rxn Is this reaction endothermic or exothermic? What is the enthalpy change if 1.25 g of NO is converted completely to NO2?arrow_forwardWater gas, a mixture of carbon monoxide and hydrogen, is produced by treating carbon (in the form of coke or coal) with steam at high temperatures. (See Study Question 83.) C(s) + H2O(g) CO(g) + H2(g) Not all of the carbon available is converted to water gas since some is burned to provide the heat for the endothermic reaction of carbon and water. What mass of carbon must be burned (to CO2 gas) to provide the energy to convert 1.00 kg of carbon to water gas?arrow_forward
- Chlorine dioxide, ClO2, is a reddish yellow gas used in bleaching paper pulp. The average speed of a ClO2 molecule at 25C is 306 m/s. What is the kinetic energy (in joules) of a ClO2 molecule moving at this speed?arrow_forwardInsoluble AgCl(s) precipitates when solutions of AgNO3(aq) and NaCl(aq) are mixed. AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq) rH = ? To measure the energy evolved in this reaction, 250. mL of 0.16 M AgNO3(aq) and 125 mL of 0.32 M NaCl(aq) are mixed in a coffee-cup calorimeter. The temperature of the mixture rises from 21.15 C to 22.90 C. Calculate the enthalpy change for the precipitation of AgCl(s), in kJ/mol. (Assume the density of the solution is 1.0 g/mL and its specific heat capacity is 4.2 J/g K.)arrow_forwardGraphite is burned in oxygen to give carbon monoxide and carbon dioxide. If the product mixture is 33% CO and 67% CO2 by mass, what is the heat from the combustion of 1.00 g of graphite?arrow_forward
- 4.60 Why are fuel additives used?arrow_forward3.83 For the reaction of nitrogen, N2, and hydrogen, H2, to form ammonia, NH3, a student is attempting to draw a particulate diagram, as shown below. Did the student draw a correct representation of the reaction? If not, what was the error the student made?arrow_forwardA newspaper article states that biomass has actually been used as an energy source throughout human history. Do you agree or disagree with this statement? Defend your answer.arrow_forward
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