Problem 12
For each of the following situations a-c, use choices i-iii to complete the statement: "The final temperature of the water should be.." i. between \(50^{\circ} \mathrm{C}\) and \(90^{\circ} \mathrm{C}\) . ii. \(50^{\circ} \mathrm{C}\) . iii. between \(10^{\circ} \mathrm{C}\) and \(50^{\circ} \mathrm{C}\) . a. 100.0 -g sample of water at \(90^{\circ} \mathrm{C}\) is added to a 100.0 -g sample of water at \(10^{\circ} \mathrm{C}\) . b. A 100.0 -g sample of water at \(90^{\circ} \mathrm{C}\) is added to a \(500.0 . \mathrm{g}\) sample of water at \(10^{\circ} \mathrm{C} .\) c. You have a Styrofoam cup with 50.0 \(\mathrm{g}\) of water at \(10^{\circ} \mathrm{C}\) . You add a 50.0 -g iron ball at \(90^{\circ} \mathrm{C}\) to the water.
Problem 13
Consider an airplane trip from Chicago, Illinois, to Denver, Colorado. List some path-dependent functions and some state functions for the plane trip.
Problem 14
How is average bond strength related to relative potential energies of the reactants and the products?
Problem 15
Assuming gasoline is pure \(\mathrm{C}_{8} \mathrm{H}_{18}(l),\) predict the signs of \(q\) and \(w\) for the process of combusting gasoline into \(\mathrm{CO}_{2}(g)\) and \(\mathrm{H}_{2} \mathrm{O}(g)\)
Problem 16
What is the difference between \(\Delta H\) and \(\Delta E ?\)
Problem 17
The enthalpy change for the reaction $$ \mathrm{CH}_{4}(g)+2 \mathrm{O}_{2}(g) \longrightarrow \mathrm{CO}_{2}(g)+2 \mathrm{H}_{2} \mathrm{O}(l) $$ is \(-891 \mathrm{kJ}\) for the reaction as written. a. What quantity of heat is released for each mole of water formed? b. What quantity of heat is released for each mole of oxygen reacted?
Problem 18
Explain why oceanfront areas generally have smaller temperature fluctuations than inland areas.
Problem 19
The equation for the fermentation of glucose to alcohol and carbon dioxide is: $$ \mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}(a q) \longrightarrow 2 \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}(a q)+2 \mathrm{CO}_{2}(g) $$ The enthalpy change for the reaction is \(-67 \mathrm{kJ} .\) Is this reaction exothermic or endothermic? Is energy, in the form of heat, absorbed or evolved as the reaction occurs?
Problem 20
Explain why \(\Delta H\) is obtained directly from coffee-cup calorimeters, whereas \(\Delta E\) is obtained directly from bomb calorimeters.
Problem 21
The enthalpy of combustion of \(\mathrm{CH}_{4}(g)\) when \(\mathrm{H}_{2} \mathrm{O}(l)\) is formed is \(-891 \mathrm{kJ} / \mathrm{mol}\) and the enthalpy of combustion of \(\mathrm{CH}_{4}(g)\) when \(\mathrm{H}_{2} \mathrm{O}(g)\) is formed is \(-803 \mathrm{kJ} / \mathrm{mol}\) . Use these data and Hess's law to determine the enthalpy of vaporization for water.
