Question 1

Which of the following is an example of a physical property of a substance?

Accepted Answer

The mass of a gold bar

Question 2

A student measures the volume and mass of a liquid sample. Which type of property is the student measuring, and why?

Accepted Answer

Physical property, because these can be measured without changing the substance's identity

Question 3

Which of the following best describes a chemical property?

Accepted Answer

The ability of hydrogen to react explosively with oxygen

Question 4

According to the law of conservation of mass, which equation correctly represents a chemical reaction where mass is conserved?

Accepted Answer

$$ \mathrm{2H_2 + O_2$ \rightarrow 2H_2O} $$

Question 5

A sample of magnesium reacts with oxygen to form magnesium oxide. If 24 g of magnesium reacts with 16 g of oxygen, what is the total mass of magnesium oxide produced, according to the law of conservation of mass?

Accepted Answer

$$ 40\ \mathrm{g} $$

Question 6

Which of the following statements about the classification of matter is correct?

Accepted Answer

A pure substance can be either an element or a compound.

Question 7

A student observes that a white powder dissolves in water without any temperature change or gas evolution. Which type of change has most likely occurred?

Accepted Answer

A physical change, because the process is reversible and no new substance is formed

Question 8

Which of the following is NOT a physical property?

Accepted Answer

Reactivity with acid

Question 9

A chemist mixes two colorless solutions and observes the formation of a yellow precipitate. Which of the following best explains this observation?

Accepted Answer

A chemical change has occurred, resulting in the formation of a new substance

Question 10

Which of the following best illustrates the law of conservation of mass in a real-world scenario?

Accepted Answer

Burning wood in a closed container, where the total mass of the container and contents remains constant

Question 11

Which of the following is a chemical property of water?

Accepted Answer

It reacts with sodium to produce hydrogen gas

Question 12

A 10.0 g sample of calcium reacts completely with 5.0 g of oxygen to form calcium oxide. If the product is weighed after the reaction, what should its mass be according to the law of conservation of mass?

Accepted Answer

$$ 15.0\ \mathrm{g} $$

Question 13

Which of the following changes is NOT a chemical change?

Accepted Answer

Melting of ice

Question 14

Which statement best describes a mixture?

Accepted Answer

A combination of two or more substances that retain their individual properties

Question 15

A student heats a blue solid and observes that it turns white and releases a gas. Which of the following best explains what has occurred?

Accepted Answer

A chemical change, because a new substance and a gas were formed

Question 16

Which of the following is an example of a chemical change that can be observed in everyday life?

Accepted Answer

Milk turning sour

Question 17

Which of the following best describes the law of conservation of mass?

Accepted Answer

The total mass of reactants equals the total mass of products in a chemical reaction

Question 18

Which of the following is a correct statement about elements and compounds?

Accepted Answer

Compounds are made up of two or more elements chemically combined in a fixed ratio

Question 19

A sealed flask contains 10 g of hydrogen and 80 g of oxygen. After a reaction occurs, water is formed. What is the mass of water in the flask after the reaction, assuming all hydrogen and oxygen react completely?

Accepted Answer

$$ 90\ \mathrm{g} $$

Basic Concepts of Chemistry: Properties of Matter and Laws of Chemical Combination

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