Chemistry - Chemical Reactions - offline version

Objectives:

• All students should know that atoms are combined in different ways when a chemical reaction happens



• Most students will understand that mass is conserved when a reaction takes place



• Some students will be able to explain the effects of pollution on the environment

National Curriculum:

Resources required:

• Class experiment lidded crucibles, magnesium ribbon, Bunsen burners, pipe-clay triangles, tripods, balances, tongs.

Teaching Activities:

Introduction

Activities

1. Class experiment / demo burning magnesium in lidded crucibles. Record mass of complete crucible with magnesium in before and after experiment (do not look at burning magnesium!). Stress that in perfect conditions, the mass would not change. If mass has changed, ask why? If lid is not airtight, oxygen may have moved inside to react with the magnesium to increase mass, or gas may have been produced which escaped if mass is less. Write up as a Scientific investigation (good opportunity for a discussion of results which do not agree with prediction, and subsequent evaluation).



2. Q. Do chemical reactions only happen during experiments in the Science Laboratory? In small groups, students have 5 minutes to list as many everyday chemical reactions as they can. Encourage students to think of wide ranging examples. Compile as one large list. Use the printable worksheet to extend ideas about different reaction types.

Summary

• Focus on chemical reaction created by car engines / fossil fuel burning. Give word equations to reinforce previous learning. Fill in flow chart showing the effects of Carbon dioxide and Nitrous Oxide on the environment. Ask students to write an ‘open letter' to the local newspaper / school magazine explaining why people can reduce the effects of pollution.

Suggested homework:

• Find newspaper articles based upon the problem of pollution, acid rain, Greenhouse Effect etc. for a wall display.