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 cannot be created or destroyed.

Question 2

A student mixes two chemicals in a beaker and observes that the beaker becomes cold to the touch. Which statement best describes the process?

Accepted Answer

The reaction is endothermic because heat is absorbed from the surroundings.

Question 3

Which equation correctly relates the change in internal energy ($$\Delta E) to $$heat ($$q) $$and work ($$w$$)?

Accepted Answer

$$\Delta E = q + w$$

Question 4

Which of the following is true for a closed system?

Accepted Answer

It can exchange heat but not mass with its surroundings.

Question 5

A gas in a piston absorbs 150 J of heat from the surroundings and does 40 J of work on the surroundings. What is the change in internal energy ($$\Delta E) of $$the system?

Accepted Answer

$$\Delta E = 110\ \mathrm{J}$$

Question 6

Which of the following is NOT a component of a thermodynamic quantity?

Accepted Answer

A color

Question 7

If $$q is $$positive for a system, what does this indicate?

Accepted Answer

The system gains heat from the surroundings.

Question 8

Which of the following best describes an isolated system?

Accepted Answer

It cannot exchange heat or mass with its surroundings.

Question 9

The electrostatic potential energy between two ions is given by $$E_{el} = \frac{kQ_1Q_2}{d}. $$What happens to $$E_{el} if $$the distance $$d$$ between the ions is doubled?

Accepted Answer

$$E_{el} is $$halved.

Question 10

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

Accepted Answer

It is the sum of both the kinetic and potential energy of a system.

Question 11

A chemical reaction in a beaker releases heat and the temperature of the solution increases. Which of the following is true?

Accepted Answer

The process is exothermic and $$q is $$negative.

Question 12

Which of the following is an example of work ($$w) in a $$chemical system?

Accepted Answer

A gas expanding against a piston.

Question 13

If a system does 75 J of work on the surroundings and loses 25 J of heat, what is the value of $$\Delta E$$?

Accepted Answer

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

Question 14

Which of the following best describes the difference between heat ($$q) $$and work ($$w$$)?

Accepted Answer

Heat is random molecular motion, while work is organized molecular motion.

Question 15

Which of the following is a state function?

Accepted Answer

Internal energy ($$E)$$

Question 16

A reaction has $$\Delta E \u003c 0. $$What does this indicate about the energy flow?

Accepted Answer

The system releases energy to the surroundings.

Question 17

Which of the following is the correct SI unit for energy?

Accepted Answer

Joule

Question 18

Which of the following best describes an open system?

Accepted Answer

It can exchange both heat and mass with its surroundings.

Question 19

Which of the following is true about the sign convention for work ($$w) in $$thermochemistry?

Accepted Answer

Work done on the system is positive.

Thermochemistry (Chapter 5) Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards