Question 1

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture in which the composition is uniform throughout, such as sugared tea.

Question 2

Which of the following is a chemical transformation?

Accepted Answer

$$4\ P(s) + 5\ O_2$(g) \rightarrow 2\ P_2O_5(s)$$

Question 3

Which of the following substances is classified as a compound?

Accepted Answer

Propane ($$C_3H_8)$$

Question 4

What does a chemical formula tell you about a compound?

Accepted Answer

The number of each type of atom in the smallest unit of the compound.

Question 5

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

Accepted Answer

Marble

Question 6

If you mix beeswax and candle wax by hand, what type of mixture do you create?

Accepted Answer

Heterogeneous mixture

Question 7

Which physical transformation describes a solid changing directly to a gas?

Accepted Answer

Sublimation

Question 8

What happens to a substance after a chemical change?

Accepted Answer

It becomes a different substance or substances.

Question 9

Which of the following is a pure substance?

Accepted Answer

Pure water

Question 10

Which state of matter has a definite shape and volume?

Accepted Answer

Solid

Question 11

A rusty iron nail is best classified as:

Accepted Answer

A heterogeneous mixture

Question 12

Which of the following is NOT a physical transformation?

Accepted Answer

$$Na(s) + Cl_2$(g) \rightarrow 2\ NaCl(s)$$

Question 13

Which of the following statements about elements is TRUE?

Accepted Answer

Elements are pure substances made of only one kind of atom.

Question 14

Which of the following is a correct chemical formula for water?

Accepted Answer

$$H_2O$$

Question 15

Which of the following best describes the role of chemistry as the 'central science'?

Accepted Answer

It bridges physics and biology, connecting material science and biochemistry.

Question 16

Which of the following is a homogeneous mixture?

Accepted Answer

Powdered lemonade dissolved in water

Question 17

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

Accepted Answer

Ice melting to form liquid water

Question 18

What is the smallest structural unit of an element?

Accepted Answer

Atom

Question 19

Which of the following best describes the transformation when ice cubes slowly vanish in a freezer?

Accepted Answer

Sublimation

Question 20

Which of the following is a correct example of a chemical reaction?

Accepted Answer

$$Na(s) + Cl_2$(g) \rightarrow 2\ NaCl(s)$$

Introduction to Chemistry: Matter, Mixtures, Elements, and Transformations

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