Science G4 Unit 3 | 3.4 Chemical reactions

When a substance changes form but the type of substance does not change is called __________.

• Physical change

• Chemical change

• Physical

• Chemical

When substances that are mixed together change and make a new substance is called __________.

• Physical change/process

• Chemical reaction/change

• Physical

• Chemical

Tick some statements that are TRUE about chemical reactions.

• Physical change and chemical change are the same processes of change of states.

• Chemical reactions make new substances form.

• A chemical reaction can happen with only one substance.

• We cannot undo a chemical reaction.

• We need heat for chemical reactions to happen.

How can we know if chemical reactions happen?

• There should be heat energy to make it activated.

• Chemical reactions make new substances form.

• Chemical reactions can happen with only one substance.

• We should undo a chemical reaction to check the process.

When we mix baking powder with vinegar, how can we know the chemical reaction takes place?

• Because it changes its taste

• Because there are new substances form (gas)

• Because it changes color

• Because it changes its smell

This picture shows an example of __________.

• Physical change/process

• Chemical reaction/change

This picture shows an example of __________.

• Physical change/process

• Chemical reaction/change

This picture shows an example of __________.

• Physical change/process

• Chemical reaction/change

This picture shows an example of __________.

• Physical change/process

• Chemical reaction/change

This picture shows an example of __________.

• Physical change/process

• Chemical reaction/change