THERMOCHEMISTRY QUIZ Part VI

1. A coffee cup calorimeter initially contains 125 g of water, at a temperature of 24.2oC. Ammonium nitrate (NH4NO3, 7.07 g), also at 24.2oC, is added to the water, and the final temperature is 18.3oC. What is the heat of solution of ammonium nitrate in kJ/mol? The specific heat capacity of the solution is 4.18 J/oC g. (Ar N = 14, O = 16, H = 1).
a. 39.5
b. 37.3
c. 34.9
d. 32.2
e. 30.1
2. A 0.0500 L sample of 0.500 M barium nitrate is added to 0.0500 L of 0.500 M magnesium sulfate in a calorimeter whose total heat capacity is 455 J/oK. The temperature increase is 1.43oK. Calculate Ho in kJ for the following reaction.
Ba(NO3)2(aq) + MgSO4(aq) --> BaSO4(s) + Mg(NO3)2(aq)
a. -32.0
b. -30.0
c. -28.0
d. -26.0
e. -24.0
3. The combustion of 0.1584 g of benzoic acid increases the temperature of a bomb calorimeter by 2.54oC. The energy released by combustion of benzoic acid is 26.42 kJ/g. A 0.2130 g sample of vanillin (C8H8O3) is then burned in the same calorimeter. The temperature increases by 3.25oC. What is the energy of combustion (kJ/mole) of vanillin?
a. 3.22 x 103
b. 3.08 x 103
c. 2.74 x 103
d. 3.46 x 103
e. 3.82 x 103
4. When 2.62 g of lactic acid, C3H6O3, is burned in a calorimeter whose heat capacity is 21.7 kJ/oK, the temperature increases by 1.800oK. Calculate the heat of combustion of lactic acid in kJ per mole. (Atomic weights: C = 12, H = 1, O = 16).
a. 3.08 x 103
b. 1.68 x 103
c. 1.54 x 103
d. 1.48 x 103
e. 1.22 x 103
5. A 50.0 g piece of copper at 100oC is put into an insulated vessel containing 250 mL of water at OoC. What will be the final temperature (oC) of the water? The specific heat of water and copper are 4.18 J/goC and 0.385 J/goC respectively.
a. 50.0
b. 7.85
c. 5.62
d. 3.25
e. 1.87
6. The specific heat capacity of graphite is 0.71 J/oC g. How much heat energy (kJ) is required to raise the temperature of 850 g of graphite by 150oC?
a. 99
b. 91
c. 86
d. 75
e. 62
7. When 325 J of heat is added to 23.6 g of octane, C8H18, the temperature increases by 6.20oC. Calculate the molar heat capacity of octane (J/moleoC). (Ar C = 12, H = 1).
a. 288
b. 254
c. 235
d. 195
e. 179
8. A 50.0 g piece of copper at 100oC is put into an insulated vessel containing 250 mL of water at OoC. What will be the final temperature (oC) of the water? The specific heat of water and copper are 4.18 J/goC and 0.385 J/goC respectively.
a. 50.0
b. 7.85
c. 5.62
d. 3.25
e. 1.87
9. The specific heat capacity of graphite is 0.71 J/oC g. How much heat energy (kJ) is required to raise the temperature of 850 g of graphite by 150oC?
a. 99
b. 91
c. 86
d. 75
e . 62
10. When 325 J of heat is added to 23.6 g of octane, C8H18, the temperature increases by 6.20oC. Calculate the molar heat capacity of octane (J/moleoC). (Ar C=12, H = 1).
a. 288
b. 254
c. 235
d. 195
e. 179