Question 1

Which of the following best describes a chemical change?
Correct answer: Iron rusting when exposed to air

Accepted Answer

Iron rusting when exposed to air

Question 2

A student mixes sand and iron filings together. Which statement best describes the resulting material?
Correct answer: It is a mixture because the components can be separated physically.

Accepted Answer

It is a mixture because the components can be separated physically.

Question 3

Which property is intensive and does NOT depend on the amount of substance present?
Correct answer: Density

Accepted Answer

Density

Question 4

A sample of gold has a mass of 96 g and a volume of 5 cm³. What is its density?
Correct answer: 19.2 g/cm³

Accepted Answer

19.2 g/cm³

Question 5

Which of the following is an example of a pure substance?
Correct answer: Carbon dioxide

Accepted Answer

Carbon dioxide

Question 6

Which scenario best illustrates a physical change?
Correct answer: Sugar dissolving in tea

Accepted Answer

Sugar dissolving in tea

Question 7

A chemist needs to separate a mixture of oil and water. Which method would be most appropriate?
Correct answer: Decanting

Accepted Answer

Decanting

Question 8

Which statement correctly distinguishes between an element and a compound?
Correct answer: Elements consist of only one type of atom, while compounds consist of two or more elements chemically bonded.

Accepted Answer

Elements consist of only one type of atom, while compounds consist of two or more elements chemically bonded.

Question 9

A 250 mL sample of ethanol has a mass of 197.5 g. What is the density of ethanol in g/mL?
Correct answer: 0.79 g/mL

Accepted Answer

0.79 g/mL

Question 10

Which of the following best explains why mass is considered an extensive property?
Correct answer: It depends on the amount of substance present.

Accepted Answer

It depends on the amount of substance present.

Question 11

A student observes that when baking soda is mixed with vinegar, bubbles form and a new substance is produced. What type of change is this, and what evidence supports your answer?
Correct answer: Chemical change; a new substance and gas are produced.

Accepted Answer

Chemical change; a new substance and gas are produced.

Question 12

Which of the following is NOT a property used to describe matter?
Correct answer: Energy

Accepted Answer

Energy

Question 13

Which of the following best describes the composition of a mixture?
Correct answer: It can vary in composition and can be separated by physical means.

Accepted Answer

It can vary in composition and can be separated by physical means.

Question 14

A hospital stores oxygen gas in large tanks. Which statement about the oxygen in the tank is correct?
Correct answer: It is a pure substance because it contains only oxygen molecules.

Accepted Answer

It is a pure substance because it contains only oxygen molecules.

Question 15

Which of the following scenarios involves both a physical and a chemical change?
Correct answer: Burning a candle (wax melting and wick burning)

Accepted Answer

Burning a candle (wax melting and wick burning)

Question 16

A 50 mL sample of a liquid has a mass of 40 g. If you pour out 10 mL, what happens to the density of the remaining liquid?
Correct answer: It remains the same

Accepted Answer

It remains the same

Question 17

Which of the following is an example of an extensive property changing while an intensive property remains constant?
Correct answer: Cutting a block of wood in half reduces its mass but not its density

Accepted Answer

Cutting a block of wood in half reduces its mass but not its density

Question 18

Which of the following best explains why density is useful for identifying substances?
Correct answer: Density is unique for each pure substance and does not depend on sample size.

Accepted Answer

Density is unique for each pure substance and does not depend on sample size.

Question 19

A student claims that dissolving sugar in water is a chemical change. Which argument best refutes this claim?
Correct answer: The sugar can be recovered by evaporating the water, showing it is a physical change.

Accepted Answer

The sugar can be recovered by evaporating the water, showing it is a physical change.

Question 20

Which of the following best describes the relationship between atoms, elements, and compounds?
Correct answer: Elements are made of atoms, and compounds are made of elements chemically bonded together.

Accepted Answer

Elements are made of atoms, and compounds are made of elements chemically bonded together.

Fundamental Concepts in Chemistry: Matter, Substances, and Properties

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