Thermo Review Chem 12
Samples:
1. How much heat must be added to a 8.21 g sample of gold to increase its temperature by
6.2 oC? The specific heat of gold is 0.13 J/goC.
2.
When a 25.7 g sample of NaI dissolves in 80.0 g of water in a calorimeter, the
temperature rises from 20.5 oC to 24.4 oC. Calculate H for the process in kJ/mole NaI.
NaI(s)  Na+(aq) + I-(aq)
H = ?
3. When a 12.8 g sample of KCl dissolves in 75.0 g of water in a calorimeter, the
temperature drops from 31.0 oC to 21.6 oC. Calculate H for the process in kJ/mole KCl.
KCl(s)  K+(aq) + Cl-(aq)
H = ?
4.
4. How much heart is required to melt 500.0 g of ice that is at 0C?
5. How much energy is released by condensing 100.0 g of steam to water at 100.0c
6. How much energy is required to convert 25.0g of ice at -10.0 C to steam at 120.0C?
7. If it takes an imput of 200.0 J of energy to melt a 25.50 g sample of lead metal, what is the heat
of fusion of lead in kJ/mole?
8. A 3.00 g sample of candle wax (C22H46) was burned in a bomb calorimeter with a C value of 8.17
kJ/C. If the temp change of the calorimeter is 7.82 C, what is the heat of combustion of candle
wax in kJ/mole?
Thermo Review Chem 12
9.
10.
11.
What happens in a calorimetry experiment if the process that you are studying is endothermic?
12. Compare endothermic and exothermic in terms of what happens to the system, the
surroundings , potential energy and the sign of ∆H
13. Write the heat of formation equation for the formation of ammonia (NH3)
14. If a reaction is endothermic, which was greater, the energy needed to break existing bonds
or the energy received from making new bonds?
Thermo Review Chem 12