Concept explainers
(a)
Interpretation:The value of
Concept Introduction : The reactions of fermentation, respiration and combustion of glucose are as follows:
- Fermentation of glucose
- Respiration
The amount of energy released on combustion of an organic compound is known as enthalpy of combustion. The formula of determination of
Here,
(a)
Answer to Problem 6.61P
Explanation of Solution
The value of standard heat of formation of compounds is as follows:
Now calculate
Fermentation of glucose
So,
Now calculate
Hence,
(b)
Interpretation:A combustion reaction for ethanol needs to be determined and whether ethanol or sugar has the higher
Concept Introduction : The amount of energy released on combustion of an organic compound is known as enthalpy of combustion. The formula of determination of
Here,
(b)
Answer to Problem 6.61P
The balanced
Ethanol has higher
Explanation of Solution
The balanced chemical reaction for combustion of ethanol is,
Use appendix B to get the value of standard heat of formation of compound.
Putting the values,
Thus, standard heat of reaction for combustion of ethanol per mole will be
The molar relationship of carbon in sugar and ethanol are as follows:
Use the molar relationships and heats of reaction of sugar and ethanol to determine the standard heat of reaction for the combustion of per mole of carbon.
Hence, ethanol has higher
Want to see more full solutions like this?
Chapter 6 Solutions
Principles of General Chemistry
- 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_forwardWhat mass of acetylene, C2H2(g), must be burned to produce 3420 kJ of heat, given that its enthalpy of combustion is 1301 kJ/mol? Compare this with the answer to Exercise 5.91 and determine which substance produces more heat per gram.arrow_forwardCompounds with carboncarbon double bonds, such as ethylene, C2H4, add hydrogen in a reaction called hydrogenation. C2H4(g)+H2(g)C2H6(g) Calculate the enthalpy change for this reaction, using the following combustion data: C2H4(g)+3O2(g)2CO2(g)+2H2O(l);H=1411kJC2H6(g)+72O2(g)2CO2(g)+3H2O(l);H=1560kJH2(g)+12O2(g)H2O(l);H=286kJarrow_forward
- When 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_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_forwardA 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_forward
- 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.arrow_forwardA 0.470-g sample of magnesium reacts with 200 g dilute HCl in a coffee-cup calorimeter to form MgCl2(aq) and H2(g). The temperature increases by 10.9 C as the magnesium reacts. Assume that the mixture has the same specific heat as water and a mass of 200 g. (a) Calculate the enthalpy change for the reaction. Is the process exothermic or endothermic? (b) Write the chemical equation and evaluate H.arrow_forwardThe combustion of 1.00 mol liquid methyl alcohol (CH3OH) in excess oxygen is exothermic, giving 727 kJ of heat. (a) Write the thermochemical equation for this reaction. (b) Calculate the enthalpy change that accompanies the burning 10.0 g methanol. (c) Compare this with the amount of heat produced by 10.0 g octane, C8H18, a component of gasoline (see Exercise 5.41).arrow_forward
- The standard enthalpy of formation of solid barium oxide, BaO, is 553.5 kJ/mol, and the standard enthalpy of formation of barium peroxide, BaO2, is 634.3 kJ/mol. (a) Calculate the standard enthalpy change for the following reaction. Is the reaction exothermic or endothermic? 2 BaO2(s) 2 BaO(s) + O2(g) (b) Draw an energy level diagram that shows the relationship between the enthalpy change of the decomposition of BaO2, to BaO and O2, and the enthalpies of formation of BaO2(s) and BaO2(s).arrow_forwardWhich of the enthalpies of combustion in Table 5.2 the table are also standard enthalpies of formation?arrow_forwardAssume 200. mL of 0.400 M HCl is mixed with 200. mL of 0.400 M NaOH in a coffee-cup calorimeter The temperature of the solutions before mixing was 25.10 C; after mixing and allowing the reaction to occur, the temperature is 27.78 C. What is the enthalpy change when one mole of acid is neutralized? (Assume that the densities of all solutions are 1.00 g/mL and their specific heat capacities are 4.20 J/g K.)arrow_forward
- General Chemistry - Standalone book (MindTap Cour...ChemistryISBN:9781305580343Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; DarrellPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781337399074Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781133949640Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage Learning
- Chemistry: Principles and PracticeChemistryISBN:9780534420123Author:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward MercerPublisher:Cengage LearningChemistry: An Atoms First ApproachChemistryISBN:9781305079243Author:Steven S. Zumdahl, Susan A. ZumdahlPublisher:Cengage LearningChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage Learning