Q: A sample of metal with a mass of 50.0 g absorbs 385 J of energy, raising its temperature from 20.0°C to 30.0°C. What is the specific heat of the metal?

$$\frac{385}{50.0 \times 10.0} = 0.77\ \mathrm{J/g$$^{\circ}$$C}$$

Q: What is the heat required to raise the temperature of 200 g of water from 25°C to 75°C? (Specific heat of water = $$4.184\ \mathrm{J/g$$^{\circ}$$C})$$

$$200 \times 50 \times 4.184 = 41,840\ \mathrm{J}$$

Q: A student heats 100 g of copper from 20°C to 120°C. If the specific heat of copper is $$0.385\ \mathrm{J/g$$^{\circ}$$C}$$, how much energy is required?

$$100 \times 100 \times 0.385 = 3,850\ \mathrm{J}$$

Q: Which equation correctly represents the calculation for heat gained or lost by a substance?

$$\text{Heat} = m \times \Delta T \times SH$$

Question 1

Which of the following is classified as a pure substance?

Accepted Answer

Aluminum foil

Question 2

Which statement best describes a homogeneous mixture?

Accepted Answer

Its composition is uniform throughout the sample.

Question 3

Which of the following is an example of a chemical change?

Accepted Answer

Iron rusting in an old car

Question 4

A sample of metal with a mass of 50.0 g absorbs 385 J of energy, raising its temperature from 20.0°C to 30.0°C. What is the specific heat of the metal?

Accepted Answer

$$\frac{385}{50.0 	imes 10.0} = 0.77\ \mathrm{J/g$$^{\circ}$$C}$$

Question 5

Which property is a chemical property?

Accepted Answer

Ability to rust

Question 6

Which process describes sublimation?

Accepted Answer

A solid changing directly to a gas without passing through the liquid state

Question 7

A plateau (horizontal line) on a heating curve represents:

Accepted Answer

A change of state

Question 8

Which of the following mixtures is heterogeneous?

Accepted Answer

Hot fudge sundae

Question 9

What is the heat required to raise the temperature of 200 g of water from 25°C to 75°C? (Specific heat of water = $$4.184\ \mathrm{J/g$$^{\circ}$$C})$$

Accepted Answer

$$200 	imes 50 	imes 4.184 = 41,840\ \mathrm{J}$$

Question 10

Which statement about gases is correct?

Accepted Answer

Gases take the shape and volume of their container.

Question 11

Which of the following is a compound?

Accepted Answer

Table salt (NaCl)

Question 12

During condensation, what happens to water molecules?

Accepted Answer

They lose kinetic energy and slow down.

Question 13

Which of the following is NOT a physical property?

Accepted Answer

Ability to react with oxygen

Question 14

A student heats 100 g of copper from 20°C to 120°C. If the specific heat of copper is $$0.385\ \mathrm{J/g$$^{\circ}$$C}$$, how much energy is required?

Accepted Answer

$$100 	imes 100 	imes 0.385 = 3,850\ \mathrm{J}$$

Question 15

Which change is a physical change?

Accepted Answer

Ice melting on the street

Question 16

Which of the following best describes a compound?

Accepted Answer

A substance composed of two or more elements chemically combined in a fixed ratio

Question 17

What is the main difference between a physical and a chemical change?

Accepted Answer

A chemical change produces new substances with different properties.

Question 18

Which of the following is a homogeneous mixture?

Accepted Answer

Sugar water

Question 19

Which equation correctly represents the calculation for heat gained or lost by a substance?

Accepted Answer

$$	ext{Heat} = m 	imes \Delta T 	imes SH$$

Question 20

Which process is the reverse of sublimation?

Accepted Answer

Deposition

Matter & Energy: Classification, Properties, and Changes (GOB Chemistry Study Notes)

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