CHE 111 Thermochem Practice
These are some practice problems. Answers are available by a hyperlink after the last
problem. You may use paper, pencil, calculator, Periodic Table, & Heats of Formation Table.
GIVEN: Specific Heat of Water is 4.184 J/g°C
1. A 42.0 g sample of water drops in temperature from 77.0°C to 50.0°C. How much heat (in kJ) is exchanged with the environment during this process? From the standpoint of the water, is the process exothermic or endothermic?
2. Methanol, CH3OH , reacts with oxygen according to the following equation:
2CH3OH(l) + 3O2(g) à 2CO2(g) + 4H2O(l)
Calculate the heat of reaction for this reaction.
3. A 75.0 g sample of silver metal at 100.0°C is added to 25.0 g of water at 23.0°C in a calorimeter. The mixture is stirred and the highest temperature observed is 33.8°C.
a) How much heat is gained by the water?
b) What is the specific heat of silver?
4. Consider the following reaction:
6Cl2(g) + 2Fe2O3(s) à 4FeCl3(s) + 3O2(g) /\H = 44.0 kJ
a) Is this reaction endo- or exothermic?
b) Does this reaction absorb or give off heat?
c) How much heat is exchanged when 87.0 g of chlorine reacts according to this reaction?