Thermodynamics Test.

1. Calculate DU for a system that does 300 kJ of work on the surroundings when 150 kJ of heat are absorbed by the system.

A) +450 kJ B) 0 kJ C) -450 kJ D) -150 kJ E)+150 kJ

2. Calculate DU for a system that absorbs 325 kJ of heat and has 65 kJ of work done on the system.

A) -260 kJ B) +390 kJ C) 0 kJ D) -390 kJ E) +260 kJ

3. Calculate DU for a system that loses 225 kJ of heat and has 150 kJ of work done on the sysyem.

A) +375 kJ B) -375 kJ C) +75 kJ D) 0 kJ E) -75 kJ

4. Calculate DU for a system that loses 325 kJ of heat while doing 200 kJ of work on the surroundings.

A) +125 kJ B) -525 kJ C) 0 kJ D) -125 kJ E) +525 kJ

5. In a certain exothermic reaction at constant pressure, DH = -75 kJ and 35 kJ of work was required to make room for products. What is DU?

A) -40 kJ B) 0 kJ C) -110 kJ D) +110 kJ E) +40 kJ

6. In a certain endothermic reaction at constant pressure, DH = +175 kJ and 45 kJ of work was required to make room for products. What is DU?

A) +220 kJ B) -220 kJ C) -130 kJ D) 0 kJ E) +130 kJ

7. For a certain reaction at constant pressure, DU = -125 kJ and 22 kJ of expansion work is done by the system. What is DH for this process?

A) -125 kJ B) +147 kJ C) +103 kJ D) -147 kJ E) -103 kJ

8. For a certain reaction at constant pressure, DU = +45 kJ and 14 kJ of expansion work is done by the system. What is DH for this process?

A) -59 kJ B) +59 kJ C) +31 kJ D) +45 kJ E) -31 kJ

9. Calculate the work needed to make room for products in the combustion of 1 mole of CH4(g) to carbon dioxide and water vapor at STP (1 L * atm = 101 J).

A) -4.52 kJ B) -2.26 kJ C) -6.79 kJ D) -11.3 kJ E) no work is needed

10. Calculate the work needed to make room for products in the combustion of 1 mole of C3H8(g) to carbon dioxide and water vapor where reactants and products are brought to STP (1 L * atm = 101 J).

A) no work is needed B) -15.8 kJ C) -13.6 kJ

D) -4.52 kJ E) -2.26 kJ

Here D represent the delta.

Answer Thermodynamics

1. D 2. B 3. E 4. B 5. C

6. E 7. E 8. B 9. E 10. E