$$\text{Total mass of reactants} = \text{Total mass of products}$$

Question 1

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

Accepted Answer

Density

Question 2

A property that can only be observed by changing the chemical composition of a substance is called:

Accepted Answer

Chemical property

Question 3

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture with uniform composition throughout

Question 4

According to the Law of Conservation of Mass, which equation is correct for a chemical reaction?

Accepted Answer

$$	ext{Total mass of reactants} = 	ext{Total mass of products}$$

Question 5

Which of the following is NOT a pure substance?

Accepted Answer

Air

Question 6

Which statement about compounds is correct?

Accepted Answer

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

Question 7

A student mixes sand and salt. This mixture is best classified as:

Accepted Answer

A heterogeneous mixture

Question 8

Which of the following changes is a chemical change?

Accepted Answer

Burning of wood

Question 9

Which of the following best illustrates the Law of Conservation of Mass in a real-world scenario?

Accepted Answer

A sealed container of hydrogen and oxygen forms water with no change in total mass

Question 10

Which of the following is a correct classification for table salt (NaCl)?

Accepted Answer

Compound

Question 11

Which property can be measured without changing the identity of a substance?

Accepted Answer

Color

Question 12

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

Accepted Answer

Salad

Question 13

Which of the following statements is true about elements?

Accepted Answer

Elements are pure substances consisting of only one type of atom

Question 14

A student observes that the mass of a closed system remains constant during a chemical reaction. This observation supports which law?

Accepted Answer

Law of Conservation of Mass

Question 15

Which of the following is NOT a chemical property?

Accepted Answer

Melting point

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

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