Physical and chemical changes

Question 1

What is a physical change?

Answer 1

when the molecules that you started with are in the same form but just in a different place

Question 2

Give an example of a physical change.

Answer 2

cutting a piece of paper or ice melting into water

Question 3

What is a chemical change?

Answer 3

the molecules you have started with are no longer in the same form

Question 4

Give an example of a chemical changes

Answer 4

mixing saliva with food or lighting a match

Question 5

What are the signs that a chemical change has occurred?

Answer 5

1. Gas or precipitate (something solidifies out of solution or reaction) forms
2. Colour change
3. Production of heat or light
4. A reaction that is often very difficult/impossible to reverse without another chemical change