Question 1

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

Accepted Answer

Density

Question 2

A student mixes sand and salt in water. Which type of matter classification does this mixture represent?

Accepted Answer

Heterogeneous mixture

Question 3

Which statement best describes a chemical property?

Accepted Answer

It is observed when a substance undergoes a chemical change.

Question 4

According to the law of conservation of mass, which equation correctly represents a chemical reaction where 10 g of reactant A reacts with 15 g of reactant B to form product C?

Accepted Answer

$$10\ \mathrm{g} + 15\ \mathrm{g} = 25\ \mathrm{g}$$

Question 5

Which of the following is NOT a pure substance?

Accepted Answer

Air

Question 6

A mixture of sugar dissolved in water is best classified as:

Accepted Answer

Homogeneous mixture

Question 7

Which of the following changes is a chemical change?

Accepted Answer

Burning of magnesium ribbon

Question 8

Which statement is true about the law of conservation of mass?

Accepted Answer

The mass of reactants is equal to the mass of products.

Question 9

Which of the following is a chemical property of iron?

Accepted Answer

It reacts with oxygen to form rust.

Question 10

Which of the following best describes a compound?

Accepted Answer

A substance composed of two or more elements chemically combined in fixed proportions.

Question 11

A student combines iron filings and sulfur powder, then heats the mixture to form iron sulfide. Which statement is correct?

Accepted Answer

A chemical change occurs, forming a compound.

Question 12

Which of the following is NOT a chemical property?

Accepted Answer

Ability to conduct electricity

Question 13

Which of the following is a correct statement about mixtures?

Accepted Answer

Mixtures can be separated by physical means.

Question 14

Which of the following is an example of a homogeneous mixture?

Accepted Answer

Salt dissolved in water

Question 15

Which process involves a physical change?

Accepted Answer

Boiling water

Question 16

A sample contains only one kind of atom. Which classification does it belong to?

Accepted Answer

Element

Question 17

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

Accepted Answer

Ice melting into water with no change in total mass

Question 18

Which statement is true about pure substances?

Accepted Answer

They have a fixed composition.

Question 19

Which of the following is a heterogeneous mixture?

Accepted Answer

Salad

Question 20

If 5 g of hydrogen reacts with 40 g of oxygen to form water, what is the mass of water formed according to the law of conservation of mass?

Accepted Answer

$$45\ \mathrm{g}$$

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

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