Question 1

Which of the following best describes the law of conservation of energy as it applies to a chemical reaction occurring in a closed container?

Accepted Answer

The total energy of the system and surroundings remains constant; energy is only transferred between them.

Question 2

A 2.0 kg object is moving at a speed of 3.0 m/s. What is its kinetic energy? Use the formula $$ KE = \frac{1}{2}mv^2$ .$$

Accepted Answer

$$ 12.0\ \mathrm{J} $$

Question 3

Which of the following is an example of potential energy in a chemical context?

Accepted Answer

A molecule of glucose storing energy in its chemical bonds.

Question 4

Which statement correctly distinguishes between heat ($$ q ) $$and work ($$ w ) in $$thermodynamics?

Accepted Answer

Heat is energy transferred due to a temperature difference, while work is energy transferred when an object is moved by a force.

Question 5

A chemical reaction in a beaker releases heat to the surroundings. Which of the following is true?

Accepted Answer

The system loses energy and $$ q  is $$negative.

Question 6

If the internal energy of a system increases by 50 J and the system does 20 J of work on the surroundings, what is the amount of heat absorbed by the system? Use $$ \Delta E = q + w .$$

Accepted Answer

$$ 30\ \mathrm{J} $$

Question 7

Which of the following best describes a state function?

Accepted Answer

A property that depends only on the initial and final states of a system, not on the path taken.

Question 8

A car engine converts chemical energy from gasoline into kinetic energy and heat. According to the first law of thermodynamics, what happens to the total energy?

Accepted Answer

The total energy remains constant; it is redistributed between kinetic energy and heat.

Question 9

Which of the following scenarios represents work being done by the system on the surroundings?

Accepted Answer

A gas expands against a piston, pushing it upward.

Question 10

Which equation correctly expresses the first law of thermodynamics for a system?

Accepted Answer

$$ \Delta E = q + w $$

Question 11

A reaction occurs in a system where $$ q = -100\ \mathrm{J} $$ and $$ w = 40\ \mathrm{J} . $$What is the change in internal energy ($$ \Delta E ) of $$the system?

Accepted Answer

$$ -60\ \mathrm{J} $$

Question 12

Which of the following is NOT a correct unit for energy?

Accepted Answer

Watt ($$ \mathrm{W} )$$

Question 13

In a pool table example, a white ball collides with a purple ball and comes to rest, while the purple ball moves away. What type of energy transfer has occurred?

Accepted Answer

Kinetic energy has been transferred from the white ball to the purple ball.

Question 14

Which of the following best describes the surroundings in a thermodynamic process?

Accepted Answer

Everything outside the system being studied.

Question 15

A reaction vessel is insulated so that no heat can enter or leave. If the system does 25 J of work on the surroundings, what is the change in internal energy ($$ \Delta E $$)?

Accepted Answer

$$ -25\ \mathrm{J} $$

Question 16

Which of the following is an example of energy being transferred as heat?

Accepted Answer

A metal spoon warming up when placed in hot tea.

Question 17

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

Accepted Answer

It is the sum of the kinetic and potential energies of all particles in the system.

Question 18

A chemical reaction absorbs 80 J of heat from the surroundings and has 30 J of work done on it by the surroundings. What is the change in internal energy ($$ \Delta E $$)?

Accepted Answer

$$ 110\ \mathrm{J} $$

Question 19

Which of the following best describes the difference between an open and a closed system in thermodynamics?

Accepted Answer

An open system can exchange both energy and matter with its surroundings, while a closed system can exchange only energy.

Thermochemistry and Energy: Study Notes for General Chemistry

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