$$\text{Density} = \frac{\text{Mass}}{\text{Volume}} = \frac{200\ \text{g}}{50\ \text{cm}^3} = 4\ \text{g/cm}^3$$

$$\Delta U = Q - W = 500\ \text{J} - 200\ \text{J} = 300\ \text{J}$$

Question 1

Which of the following best explains why ice floats on water, even though most solids sink in their own liquid form?

Accepted Answer

Ice has a lower density than liquid water because its molecules are arranged farther apart.

Question 2

A metal block has a mass of 200 g and a volume of 50 cm$$^3. $$What is its density?

Accepted Answer

$$	ext{Density} = \frac{	ext{Mass}}{	ext{Volume}} = \frac{200\ 	ext{g}}{50\ 	ext{cm}^3} = 4\ 	ext{g/cm}^3$$

Question 3

Which method of heat transfer is primarily responsible for the warming of the Earth's mantle, as shown in the diagram of mantle convection?

Accepted Answer

Convection

Question 4

A pot is heated on a stove. The handle becomes hot after a few minutes. Which method of heat transfer is responsible for this?

Accepted Answer

Conduction

Question 5

Which of the following statements is a direct consequence of the First Law of Thermodynamics?

Accepted Answer

The total energy of an isolated system remains constant; it can only change forms.

Question 6

If 500 J of heat is added to a system and the system does 200 J of work, what is the change in the system's internal energy ($$\Delta U$$)?

Accepted Answer

$$\Delta U = Q - W = 500\ 	ext{J} - 200\ 	ext{J} = 300\ 	ext{J}$$

Question 7

Which of the following best describes entropy?

Accepted Answer

A measure of the degree of randomness or disorder in a system.

Question 8

Why does heat flow from a hot object to a cold object, according to the Second Law of Thermodynamics?

Accepted Answer

Because systems naturally move toward higher entropy (more disorder).

Question 9

Which of the following is NOT a method of heat transfer?

Accepted Answer

Compression

Question 10

A heat lamp keeps food warm in a restaurant. Which method of heat transfer is primarily responsible?

Accepted Answer

Radiation

Question 11

Which temperature scale is based on the concept of absolute zero, where all molecular motion stops?

Accepted Answer

Kelvin

Question 12

What happens to the density of most materials as temperature increases?

Accepted Answer

Density decreases because particles move farther apart.

Question 13

Which of the following real-life scenarios is an example of convection?

Accepted Answer

The circulation of air in the atmosphere.

Question 14

According to the Third Law of Thermodynamics, what happens to entropy as temperature approaches absolute zero?

Accepted Answer

Entropy becomes zero.

Question 15

Which of the following best describes the relationship between temperature and the average kinetic energy of particles in a substance?

Accepted Answer

Temperature is a measure of the average kinetic energy of the particles.

Question 16

A student claims that heat can travel through empty space. Which method of heat transfer supports this claim?

Accepted Answer

Radiation

Question 17

A block of aluminum (density = 2.7 g/cm$$^3) $$and a block of iron (density = 7.9 g/cm$$^3) $$are placed in water. Which statement is correct?

Accepted Answer

Both blocks will sink because their densities are greater than water.

Question 18

Which of the following is an example of increasing entropy in a real-world scenario?

Accepted Answer

A clean room becoming messy over time.

Question 19

Which equation correctly expresses the relationship between density, mass, and volume?

Accepted Answer

$$	ext{Density} = \frac{	ext{Mass}}{	ext{Volume}}$$

Heat, Density, and Thermodynamics: Study Notes

스터디 가이드 - 연습 문제