Kaupapa: 24 / 05 Wednesday Describe the evidence of chemical reactions Describe the difference between chemical changes and physical changes

Do you remember? How do we test for carbon dioxide? How do we test for oxygen? How do we test for hydrogen?

Practical: Chemical Reaction OR Physical Reaction?

Practical: Chemical Reaction OR Physical Reaction? 7 Experiments 7 Stations 7 Groups Rotate every 5 minutes Write down detailed observation

1. Iron nail in copper sulfate solution

2. Heating up sugar

3. Heating up egg white

4. Heating up a piece of chocolate

5. Potassium iodide + Lead nitrate

6. Magnesium + Hydrochloric acid

7. Baking soda + Vinegar

Which do you think is (are) chemical reactions? Why? Which do you think is (are) physical reactions? Why?

Summary Questions What differences are there between chemical reactions and physical reactions? What are the evidence of chemical reactions? Define a chemical reaction in your own words!

Evidence of a Chemical Reaction Heat being produced (or absorbed) Gas being produced (e.g. bubbles) Changes in properties (e.g. colour, texture, smell, etc.) New substance(s) formed Irreversible (cannot go back)

A Chemical Reaction is… When two or more substances produce one or more new chemical compound(s), or changes the properties of the reactants. Most chemical reactions are irreversible.

What have we learnt today? What are some of the things you can observe in chemical reactions? Describe two differences between chemical reactions and physical reactions