Sub And Prop

Question 1

What is a physical change?

Answer 1

In a physical change, the original substance still exists; it only changes in form.

Question 2

What is a chemical change?

Answer 2

In a chemical change, a new substance is produced. Energy changes always accompany chemical changes.

Question 3

Hydrochloric acid reacts with potassium hydroxide to produce a salt, water, and heat. Classify this change.

Answer 3

Chemical change.

Question 4

A pellet of sodium is sliced in two. Classify this change.

Answer 4

Physical change.

Question 5

Water is heated and changed to steam. Classify this change.

Answer 5

Physical change.

Question 6

Potassium chlorate decomposes to potassium chloride and oxygen gas. Classify this change.

Answer 6

Chemical change.

Question 7

Iron rusts. Classify this change.

Answer 7

Chemical change.

Question 8

Ice melts. Classify this change.

Answer 8

Physical change.

Question 9

Acid on limestone produces carbon dioxide gas. Classify this change.

Answer 9

Chemical change.

Question 10

Milk sours. Classify this change.

Answer 10

Chemical change.

Question 11

Wood rots. Classify this change.

Answer 11

Physical change.