1) The specific heat of aluminum is 0.214 cal/g°C. Calculate the heat in joules necessary to raise the temperature of 40.0g of Aluminum from 20.0°C to 32.3°C. 439 J 2) Determine the final temperature of a system after 100.0g of zinc at 95°C is immersed in to 50.0g of water at 15°C. The molar heat capacity of zinc is 25.4 J/mol K. Tf = 28°C 3) The heat of combustion of carbon to CO2 is -393.5 kJ/mol. Calculate the heat released upon formation of 35.2g of CO2 from carbon and oxygen gas. -3l5 kJ 4) Calculate ∆Hf° of C6H12O6(s) from the following data: ∆Hcomb° of C6H12O6(s)= -2816 kJ/mol ° ∆Hf of CO2(g) = -393.5 kJmol ° ∆Hf of H2O(/) = -285.9 kJ/mol -1260 kJ/mol 5) Calculate the standard enthalpy change, ΔHo, for the formation of 1 mol of strontium carbonate (the material that gives the red color in fireworks) from its elements. SrCO3(s) → Sr(s) + C(graphite) + 3/2 O2(g) The information available is: (1) 2Sr(s) + O2(g) → 2SrO(s) ∆H° = -1184 kJ (2) SrO(s) + CO2(g) → SrCO3(s) ∆H° = -234 kJ (3) C(graphite) + O2(g) → CO2(g) ∆H° = -394 kJ +1220 kJ/mol 6) Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values: HCl(g) + NaNO2(s) → HNO2(l) + NaCl(s) 2NaCl(s) + H2O(l) → 2HCl(g) + Na2O(s) ΔH = 507 kJ NO(g) + NO2(g) + Na2O(s) → 2NaNO2(s) ΔH = -427 kJ NO(g) + NO2(g) → N2O(g) + O2(g) ΔH = -43 kJ 2HNO2(l) → N2O(g) + O2(g) + H 2O(l) ΔH = 34 kJ Answer = -78 kJ 7) Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values: Zn(s) + 1/8S8(s) + 2O2(g) → ZnSO4(s) 8Zn(s) + S8(s) → 8ZnS(s) ΔH = -1471.36 kJ 2ZnS(s) + 3O2(g) → 2ZnO(s) + 2SO2(g) ΔH = -927.54 kJ 2SO2(g) + O2(g) → 2SO3(g) ΔH = -196.04 kJ ZnSO4 (s) → ZnO(s) + SO3(g) ΔH = +230.32 kJ Answer = -976.03 kJ 8) A 235.00g piece of copper (which has a molar heat capacity of 14.54 J/Cmol) is heated to 92.5C and dropped into a calorimeter containing 122.50 g of water initially at 24.3C. What is the final temperature of the water? Tf=30.7°C 9) Consider the following reaction: 4PCl5(g) → P4(s) + 10Cl 2(g) ΔH = +3438 kJ a) Is there more energy in the products or reactants? b) Calculate the heat change when 40.0 g P4(s) is produced. +1110kJ c) How many grams of PCl5(g) are required to produce 1.00 kJ of energy? 0.242g PCl5(g) 10) A liquid used in a calorimeter can absorb 2.24 kJ of heat for every 1.0oC that it increases. An 11.2 g sample of nitroglycerin (molar mass = 227.11 g/mol) was ignited, and the liquid’s temperature increased from 23.3 °C to 75.5 °C. Find the molar heat of decomposition for nitroglycerin. -2370kJ/mol 11)Use the experimental data given below to determine the value for the molar heat of the reaction for the combustion of strontium: -928.8kJ Sr(s) + ½ O2(g) → SrO(s) Each reaction was carried out in a calorimeter while temperature change was recorded. Assume that no heat was lost to the calorimeter and that HCl was in excess. Reaction Sr(s) + 2HCl(ag) → SrCl2(ag) + H2(g) SrO(s) + 2HCl(ag) → SrCl2(ag) + H2O(l) H2(g) + (1/2)O2(g) → H2O(l) ∆H= -286kJ Mass of reactant Sr= 2.00g SrO= 1.00g ----------- Mass of Water 160.0g 120.0g ----------- ∆T (˚C) 37.0 8.5 ---------