AP Chemistry - Calorimetry Worksheet
1.  When sulphuric acid dissolves in water, a great deal of heat is given off. The enthalpy change for this process is called the enthalpy of solution. To measure it, 175 g of water was placed in a coffee-cup calorimeter and chilled to 10oC. Then 49.0 g of pure sulphuric acid, also at 10.0oC was added, and the mixture was quickly stirred with a thermometer. The temperature rose rapidly to 14.9oC. Assume that the value of the specific heat of solution is 4.184 J/goC. You may assume that the specific heat of the resulting sulphuric acid solution will also be 4.184 J/goC. Calculate q for the formation of this solution, and calculate the enthalpy of solution in kilojoules per mole of H2SO4
2. Gram for gram, fats in food have much more chemical energy than sugar. One component of fat is stearic acid, C18H36O2. When a sample of 1.02 g of stearic acid was burned completely in a bomb calorimeter, the temperature of the calorimeter rose by 4.26oC. The heat capacity of the calorimeter was 9.43 kJ/oC. Calculate the molar heat of combustion of stearic acid in kilojoules per mole.
3. The reaction of 2.000 mol of gaseous hydrogen with 1.000 moles of gaseous oxygen to form 2.00 mol of liquid water releases 517.8 kJ, provided that all reactants and products are brought to 25oC and 1 at. Write a thermochemical equation for the formation of 1.00 mol of liquid water.
4. Ethanol, C2H5OH, is made industrially by the reaction of water with ethylene, C2H44. Calculate the value of Ho for the reaction 

C2H4(g) + H2O(l) ----> C2H5OH(l)

given the following thermochemical equations: 

C2H4(g) + 3 O2(g) ----> 2 CO2(g) + 2 H2O(l) Ho = -1411.1 kJ 

C2H5OH(l) + 3 O2(g) ---> 2 CO2(g) + 3 H2O(l) Ho = -1367.1 kJ