PROBLEM SET # 18 SECTION 2 Name:_______________________________ Student No.: _________________________ Q1) When 33.0 g of an unknown metal at 16.4°C is placed in an insulated container holding 60.0 g of H2O at 79.5°C, the water temperature decreases to 76.8°C. The specific heat capacity of water is 4.184 J/g∙K. What is the specific heat capacity of the metal? ________________ Q2) Using the following data: ΔHfus = 333 J/g; ΔHvap = 2256 J/g; Sice = 2.06 J/g∙K; Swater = 4.184 J/g∙K; Ssteam = 1.92 J/g∙K, how much heat is required to change 50.0 grams of water at 35.0°C to gas at 105.0°C? ________________ Q3) What mass of ammonia is necessary to produce 400 kJ of heat? 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g) ΔHr = –906 kJ/mol _________________ Q4) Commercial cold packs consist of solid ammonium nitrate and water. NH4NO3 absorbs 25.69 kJ of heat per mole when dissolved in water. In a coffee‐cup calorimeter, 4.30 g NH4NO3 is dissolved in 80.0 grams of water at 21.0°C. What is the final temperature of the solution? (Assume the solution has a specific heat capacity of 4.18 J/g∙K.) [2 marks] _________________ /5