1. Chemical Reactions

2. What is a chemical reaction?
Think, pair, share.
Think quietly then discuss with your neighbour what
you think a chemical reaction is. Be prepared to share
your answer.

3. What is a chemical reaction?
“ a chemical reaction occurs when two or more
chemicals join together to form a new substance”

4. Chemical Reactions Think, pair, share.
Can you think of any chemical reactions that you
have come across already in Science? Be
prepared to share your answer

5. Chemical reactions – What to look for
There may be a change of colour

6. Chemical reactions – What to look for
There may be a gas given off (bubbles)

7. Chemical reactions – What to look for
There may be an energy change – temperature increases or decreases

8. How do we know a chemical reaction is happening?
Some or all of the below things can happen during a chemical reaction as new substances are formed:-
Change of colour
Change of temperature (up or down)
Bubbles of gas maybe produced (effervescence)

9. Class Practical
For each of the experiments you are going to carry out, you need to record your observations, then decide if a chemical reaction is happening.

10. Class Practical Experiment Observations Experiment 1 Magnesium +
Oxygen
Experiment 2
Sodium carbonate
Hydrochloric acid
Experiment 3
Sodium hydroxide
Experiment 4
Hydrochloric Acid
Experiment 5
Ethanoic acid
Potassium Iodide
Lead nitrate

11. Task  Investigating chemical reactions
Record your observations on the worksheet
Complete the word and symbol equations
Extension: Balance the symbol equations