Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

1. Which condition leads to an increase in the internal energy of a system? -10

ID: 1464246 • Letter: 1

Question

1. Which condition leads to an increase in the internal energy of a system?

-10 J of heat are released by the system, and 3 J of work are done on the system.

-6 J of heat are released by the system, and -3 J of work are done by the system.

6 J of heat are gained by the system, and- 3 J of work are done by the system.

3 J of heat are gained by the system, and -6 J of work are done by the system.

-6 J of heat are released by the system, and 3 J of work are done by the surroundings.

3. The value of DH° for the reaction below is -186 kJ.

2 HCl (g) à H2 (g) + Cl2 (g)

The value for DH°f (kJ/mol) of HCl (g) is _______.

a. +186            b. -3.72 x 102               c. -93.0            d. -1.27 x 102               e. -186       f. +93.0

4. In order to ensure that comparisons of changes in enthalpy for reactions can be made, measurements of changes in enthalpy must be made under the conditions of:

298 K, 1 atm pressure, and 1 M concentration.

273 K, 1 atm pressure, 1 M concentration, and specified physical states.

298 K, 1 atm pressure, 1 M concentration for ions, and specified physical states.

25°C, 1 atm pressure, 1 M concentration, and specified physical states.

273 K, 1 atm pressure, and 1 M concentration.

Explanation / Answer

1) 6 J of heat are gained by the system, and- 3 J of work are done by the system.

2) f. +93.0

3)25°C, 1 atm pressure, 1 M concentration, and specified physical states.