10
lesson pretestMultiple Choice

Pretest

Question 10 • Chemistry

Which of these is an example of a physical change?

Answer
A
wood burning in the presence of oxygen
B
baking soda reacting with acid to form a gas
C
iron rusting in the presence of moist air
D
sugar dissolving in warm water

Explanation

A physical change alters a material’s form or state without creating a new substance. When sugar dissolves in warm water, the sugar molecules remain sugar and can be recovered by evaporating the water. The other choices involve chemical reactions that produce new substances, such as gas, rust, or ash.

AI-written and checked against the verified answer.