Question 1

Which of the following best describes the first law of thermodynamics?

Accepted Answer

Energy can be converted from one form to another, but it is neither created nor destroyed.

Question 2

A chemical reaction in a closed system releases 500 J of heat to the surroundings and does 200 J of work on the surroundings. What is the change in internal energy ($$\Delta E) of $$the system?

Accepted Answer

$$\Delta E = -700\ \mathrm{J}$$

Question 3

Which of the following is a state function?

Accepted Answer

Internal energy ($$U)$$

Question 4

Which type of system allows exchange of both heat and mass with its surroundings?

Accepted Answer

Open system

Question 5

A gas in a piston absorbs 300 J of heat from the surroundings and the piston does 100 J of work on the gas. What is the change in internal energy ($$\Delta E) of $$the gas?

Accepted Answer

$$\Delta E = 400\ \mathrm{J}$$

Question 6

Which equation correctly relates the change in internal energy to heat and work for a closed system?

Accepted Answer

$$\Delta E = q + W$$

Question 7

Which of the following is NOT a form of potential energy?

Accepted Answer

Kinetic energy ($$E_k = \dfrac{1}{2}mv^2$)

Question 8

Which statement about thermal energy is correct?

Accepted Answer

Thermal energy is a measure of the average kinetic energy of particles in a system.

Question 9

If a system releases energy as heat to the surroundings, what is the sign of $$q$$ for the system?

Accepted Answer

$$q is $$negative

Question 10

Which of the following best describes an isolated system?

Accepted Answer

It cannot exchange heat or mass with its surroundings.

Question 11

Which of the following processes is favored in a closed system according to the second law of thermodynamics?

Accepted Answer

Processes that increase the total entropy ($$\Delta S \u003e 0)$$

Question 12

Which of the following is true about state functions?

Accepted Answer

Their values depend only on the current state, not the path.

Question 13

Which formula represents the kinetic energy of a moving object?

Accepted Answer

$$E_k = \dfrac{1}{2}mv^2$

Question 14

A reaction in a closed system absorbs 250 J of heat and the system does 150 J of work on the surroundings. What is the change in internal energy ($$\Delta E$$)?

Accepted Answer

$$\Delta E = +100\ \mathrm{J}$$

Question 15

Which of the following is NOT a state function?

Accepted Answer

Work ($$W)$$

Question 16

Which of the following statements about the third law of thermodynamics is correct?

Accepted Answer

A system's entropy approaches a constant value as the temperature approaches absolute zero.

Question 17

Which of the following best describes the difference between heat and temperature?

Accepted Answer

Temperature is a measure of the average kinetic energy of particles, while heat is energy transferred due to a temperature difference.

Question 18

Which equation represents the electrostatic potential energy between two ions?

Accepted Answer

$$E = \dfrac{kQ_1Q_2}{r}$$

Question 19

Which of the following statements about internal energy ($$U) is $$correct?

Accepted Answer

Internal energy is a state function that includes both kinetic and potential energies of the system.

Question 20

Which of the following is true regarding energy changes during bond formation and bond breaking?

Accepted Answer

Bond formation releases energy, while bond breaking consumes energy.

Thermochemistry: Energy, Chemical Reactions, and Thermodynamics

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