Ch7 Example Problems

# Ch7 Example Problems - c –6.00 kJ/mol d 12.00 kJ/mol 4...

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HODSON CHE 1301 Petrucci Ch7 Example Problems The following problems are taken from old exams . ..... 1) 100.0 g of nickel at 150.0 °C was placed in 1.00 L of water at 25.0 °C. The final temperature of the nickel-water mixture was 26.3 °C. What is the specific heat of the nickel? a) 0.554 b) 0.130 c) 2.28 d) 0.439 e) 0.144 2) Cyclohexanol, C 6 H 12 O, has a heat of combustion (q rxn ) of –890.7 kcal/mol. 0.708 g of cyclohexanol undergoes complete combustion in a bomb calorimeter that has a heat capacity of 2.70 kcal/°C. What is the final temperature if the initial water temperature is 27.0 °C? a) 29.3°C b) 27.4 °C c) 24.7 °C d) 26.6 °C e) 31.4 °C 3) Two solutions, 250.0 mL of 1.00 M CaCl 2(aq) and 250.0 mL of 1.00 M K 2 CO 3(aq) , were added to a calorimeter with a heat capacity of 1.25 kJ/°C and the temperature decreased by 2.40 °C. Determine q rxn per mole of CaCO 3(s) formed in the reaction. a) –12.0 kJ/mol b) +6.00 kJ/mol

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Unformatted text preview: c) –6.00 kJ/mol d) +12.00 kJ/mol 4) Calculate ΔU for a system that loses 475 kJ of heat and does 155 kJ of expansion work on the surroundings a) +320 kJ b) –630 kJ/mol c) –320 kJ d) +630 kJ 5) Combine the reactions: P 4(s) + 6 Cl 2(g) → 4 PCl 3(g) Δ H ° = –1225.0 kJ PCl 3(g) + 3 H 2 O (l) → H 3 PO 3(aq) + 3 HCl (g) = – 853.5 kJ 2 H 2(g) + O 2(g) → 2 H 2 O (l) = – 571.5 kJ H 2(g) + Cl 2(g) → 2 HCl (g) = – 184.9 kJ to obtain the reaction: P 4(s) + 6 H 2(g) + 6 O 2(g) → 4 H 3 PO 3(aq) What is the value of Δ H ° for this reaction? a) –9177.4 kJ b) 8605.9 kJ c) –2465.1 kJ d) –6958.6 kJ e) –2834.9 kJ 6) Consider the reaction: 4 NH 3(g) + 5 O 2(g) → 4 NO 2(g) + 6 H 2 O (l) Δ H ° f –46.19 0.00 90.37 –285.85 kJ/mol Compute Δ H ° for this reaction. a) –622.62 kJ b) -241.67 kJ c) -1168.9 kJ d) -149.29 kJ e) 984.10 kJ...
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Ch7 Example Problems - c –6.00 kJ/mol d 12.00 kJ/mol 4...

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