Chemistry, The Central Science, 11th edition Theodore L. Brown; H. Eugene LeMay, Jr.; Bruce E. Bursten and Catherine J. Murphy Chapter 5 Thermochemistry Donna Narsavage Heald Siena College Loudonville, NY 2009, Prentice-Hall Which metal will undergo the greatest temperature change if an equal amount of heat is added to each? 1. 2. 3. 4. 5. Fe, s = 0.45 J/g K Al, s = 0.90 J/g K Cu, s = 0.38 J/g K Pb, s = 0.13 J/g K Sn, s = 0.22 J/g K Which metal will undergo the greatest temperature change if an equal amount of heat is added to each? 1. 2. 3. 4. 5. Fe, s = 0.45 J/g K Al, s = 0.90 J/g K Cu, s = 0.38 J/g K Pb, s = 0.13 J/g K Sn, s = 0.22 J/g K If a piece of metal at 85°C is added to water at 25°C, the final temperature of the system is 30°C. Which of the following is true? 1. 2. 3. 4. 5. Heat lost by the metal > heat gained by water. Heat gained by water > heat lost by the metal. Heat lost by metal > heat lost by the water. Heat lost by the metal = heat gained by water. More information is required. If a piece of metal at 85°C is added to water at 25°C, the final temperature of the system is 30°C. Which of the following is true? 1. 2. 3. 4. 5. Heat lost by the metal > heat gained by water. Heat gained by water > heat lost by the metal. Heat lost by metal > heat lost by the water. Heat lost by the metal = heat gained by water. More information is required. Which reaction represents the DHf reaction for NaNO3? 1. 2. 3. 4. 5. Na+ (aq) + NO3- (aq) NaNO3 (aq) Na+ (g) + NO3- (g) NaNO3 (s) Na (s) + NO3 (s) NaNO3 (s) 2 Na (s) + N2 (g) + 3 O2 (g) 2 NaNO3 (s) 2 Na (s) + 1/2 N2 (g) + 3/2 O2 (g) NaNO3 (s) Which reaction represents the DHf reaction for NaNO3? 1. 2. 3. 4. 5. Na+ (aq) + NO3- (aq) NaNO3 (aq) Na+ (g) + NO3- (g) NaNO3 (s) Na (s) + NO3 (s) NaNO3 (s) 2 Na (s) + N2 (g) + 3 O2 (g) 2 NaNO3 (s) 2 Na (s) + 1/2 N2 (g) + 3/2 O2 (g) NaNO3 (s) Which of the following statements is true for the diagram? 1. 2. 3. 4. 5. Internal energy > 0 Internal energy < 0 Enthalpy > 0 Enthalpy < 0 Internal energy = enthalpy System Surroundings heat work Which of the following statements is true for the diagram? 1. 2. 3. 4. 5. Internal energy > 0 Internal energy < 0 Enthalpy > 0 Enthalpy < 0 Internal energy = enthalpy System Surroundings heat work What is the value of the unknown DH in the diagram? 1. 2. 3. 4. 5. +329.5 kJ –329.5 kJ +285.8 kJ –241.8 kJ +241.8 kJ DH = –285.8 kJ H2 (g) + 1/2 O2 (g) DH = ? H2O (g) DH = –44.0 kJ H2O (l) What is the value of the unknown DH in the diagram? 1. 2. 3. 4. 5. +329.5 kJ –329.5 kJ +285.8 kJ –241.8 kJ +241.8 kJ DH = –285.8 kJ H2 (g) + 1/2 O2 (g) DH = ? H2O (g) DH = –44.0 kJ H2O (l)