CHEMICAL ENERGY CONSIDERATIONS
1) A HEAT PROBLEM INVOLVING BUTANE AND WATER
A) Write the balanced equation for the combustion of butane.
B) The heat of combustion for butane is 2859 kJ/mol butane. Add this value to the above equation in an
appropriate manner.
C) If all the heat from the combustion of 0.20 grams of butane was used to heat 6.00 grams of water at an
initial temperature of 70.0 C, would the water reach the boiling point?
D) Would all the water boil away or would some be left “unvaporized”? Or would there be energy “left
over”? You must show calculations to support your answers. (The specific heat of liquid water is
4.18 J/g C. The heat of vaporization of water is 40.7 kJ/mol.)
2) ANOTHER HEAT PROBLEM
0.500 L of 1.00 M barium nitrate at 25.0 C is reacted with 0.500 L of 1.00 M sodium sulfate at 25.0 C in
a calorimeter. The temperature increases to 26.5 C as barium sulfate forms. Assume that Csoln = Cwater
,that the density of the solution = 1g/mL, and that final volume is additive for two solutions.
(A) What is the enthalpy change for the reaction as performed?
(B) Write the balanced equation for this reaction.
What is the enthalpy change for the reaction as written in the balanced equation?
(C) If you were to react 200. grams of barium nitrate and 200. grams of sodium sulfate according to the
balanced equation, how much heat energy would be released?