Chemical reaction? Food color. Which photo shows a physical change and which shows a chemical reaction?

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Mavis Dickerson
6 years ago
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1 Chemical reactions

2 Chemical reaction? Food color Which photo shows a physical change and which shows a chemical reaction?

3 Starter: chemical reactions

4 Aim 17 May 2016 By the end of this lesson I will be able to recognise when a chemical reaction is taking place Key words Chemical reaction Product Reactant Word equation

5 Have you ever wondered What would happen if we could make gold in a chemical reaction? The bigger picture

6 Chemical reactions Write down as many ways that you know a chemical reaction is taking place colour changes gives out a gas produces a solid cools down glows heats up flashes produces smoke

7 How can you spot a chemical reaction? Lots of changes happen in chemical reactions. You might recognize that a chemical reaction is happening because the substances involved: change colour give off a gas get hot get cold give out light make smells form solids.

8 Chemical reactions You will now perform 4 experiments. Before you start, have a look at your worksheet.

9 Chemical reactions What evidence is there in each case that a chemical reaction has taken place? Remember, that in a chemical reaction, new materials are produced.

10 Wear your goggles and tie your hair back

11 8F Compounds in chemical reactions Perform the experiments 1 Sodium carbonate and iron II chloride 1. Add a small amount of iron chloride to 3 cm depth of water in a test tube and shake gently until the solid dissolves. 2. Pour 3 cm depth of sodium carbonate solution into a second test tube. 3. Slowly add the iron chloride solution to the sodium carbonate solution. Magnesium carbonate and hydrochloric acid 1. Put a small amount of magnesium carbonate into a test tube and add 3 cm depth of dilute hydrochloric acid.

12 8F Compounds in chemical reactions Perform the experiments 2 Copper (II) sulphate solution and sodium hydroxide 1. Put 3 cm depth of copper(ii) sulphate solution into a test tube 2. Slowly add sodium hydroxide solution. Silver nitrate and potassium iodide 1. Pour 3 cm depth of silver nitrate into a test tube 2. Add a small amount of potassium iodide solution.

13 8F Compounds in chemical reactions Chemical equations Take a look at these chemical reactions and match the reactants and products. hydrochloric + magnesium acid carbonate sodium + iron carbonate chloride copper + ammonia sulphate carbon ammonium + water + + copper magnesium dioxide sulphate chloride carbon iron + water sodium carbonate chloride ammonium iron + sodium copper carbonate sulphate chloride sucrose carbon + water + + magnesium water dioxide chloride

14 Reactants and products In a chemical reaction, one or more new substances are always formed. The starting substances used in a reaction are the reactants. The new substances formed in a reaction are the products. reactants products The arrow means change into. In a chemical reaction, the reactants change into the products. It is often difficult to reverse a chemical reaction and change the products back into the reactants.

15 Word equations A word equation is a quick, shorthand way of writing a chemical reaction. There are always three parts to a word equation: the names of the reactants an arrow the names of the products. What is the word equation for hydrogen reacting with oxygen to form water? hydrogen + oxygen water

16 Reactant or product? In this chemical reaction, which substances are the reactants and which substances are the products? copper magnesium magnesium + oxide + copper oxide substance magnesium oxide magnesium copper oxide copper reactant or product? product reactant reactant product

17 Write the word equations Magnesium burns brightly in oxygen to form magnesium oxide. magnesium + oxygen magnesium oxide Calcium hydroxide reacts with hydrochloric acid to form calcium chloride and water. calcium hydroxide hydrochloric acid calcium chloride + + water Sodium reacts with hydrochloric acid to form sodium chloride and hydrogen. sodium hydrochloric acid sodium chloride + + hydrogen

18 Plenary 1) Each pupil is presented with one card on which a chemical is written. 2) Look around and find other pupils to team up with to present a word equation. 3) The winners are those who first present a complete reaction with reactants on the left and products on the right. 4) Ask pupils to step forward or raise their cards if they are: a) an element b) A compound c) a reactant d) a product.

19 Key words 17 May 2016 Chemical reaction - A change in which new substances are made and which cannot easily be reversed Product - The new substances produced in a chemical reaction and shown on the right of a word equation Reactant - The starting substances used in a chemical reaction and shown on the left of a word equation Word equation - A summary of a chemical reaction

5. Researching the properties of particular materials and understand why they are used for particular products.

5. Researching the properties of particular materials and understand why they are used for particular products. 1. The difference between a physical and chemical change. 2. How to identify whether a physical or chemical change has taken place. 3. Understand what reactants and products are. 4. Writing and understanding