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NATIONAL 4/5 CHEMISTRY CHEMICAL CHANGES AND STRUCTURE LESSON 1 REVISION OF FACTORS THAT SPEED UP A REACTION.

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Presentation on theme: "NATIONAL 4/5 CHEMISTRY CHEMICAL CHANGES AND STRUCTURE LESSON 1 REVISION OF FACTORS THAT SPEED UP A REACTION."— Presentation transcript:

1 NATIONAL 4/5 CHEMISTRY CHEMICAL CHANGES AND STRUCTURE LESSON 1 REVISION OF FACTORS THAT SPEED UP A REACTION

2 A working knowledge of the factors affecting rates of reaction is required for this Course. To compare rates of chemical reactions, changes in mass, volume and other quantities can be measured. Graphs can then be drawn to help this comparison. National 4 Chemistry: Rates of reaction Reactions monitored and graphs interpreted Previous Learning from S3: Through experimentation, I can identify indicators of chemical reactions having occurred. I can describe ways of controlling the rate of reactions and can relate my findings to the world around me. SCN 3-19a Describe how the following affect the speed of a reaction: particle size concentration Temperature State that catalysts are substances which: speed up some reactions are not used up during the reaction can be recovered chemically unchanged

3 Important Point to note: in order for chemists to monitor the rate of a reaction we must observe a CHANGE in response to a chemical change occurring. Reactants changing to products

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8 Rates of Reaction Effect of concentration Effect of catalysts Introduction Summary activitiesEffect of temperature Contents Effect of surface area

9 Rates of reactions The speed of different chemical reactions varies hugely. Some reactions are very fast and others are very slow. fast very fast very slow fast slow Burning magnesium fireworks chemical weathering of rocks sodium and water rotting fruit Reaction Rate What is the rate of these reactions? The speed of a reaction is called the rate of the reaction.

10 Reactions occur when particles of reactants collide with enough energy to react (activation energy).

11 Rates of Reaction Effect of concentration Effect of catalysts Introduction Summary activities Effect of temperature Effect of surface area Contents

12 Temperature and rate of reaction video WATCH THE VIDEO TEMPERATURE AND RATE OF REACTION VIDEO!

13 The effect of temperature on collisions How does temperature affect the rate of particle collision?

14 Temperature and particle collisions

15 Rates of Reaction Effect of concentration Effect of catalysts Introduction Summary activities Effect of temperature Effect of surface area Contents

16 Concentration and reaction rate video 3% hydrogen peroxide solution 30% hydrogen peroxide solution Add more solute (hydrogen peroxide) to the same volume WATCH THE CONCENTRATION AND REACTION RATE VIDEO!

17 Increasing concentration

18 Concentration Reactions in solution involve dissolved particles. The more crowded (concentrated) the solution, the faster the reaction. Higher concentration  more particles  more collisions  faster reaction

19 Rates of Reaction Effect of concentration Effect of catalysts Introduction Summary activities Effect of temperature Effect of surface area Contents

20 Surface area and reaction rate video WATCH THE SURFACE AREA AND REACTION RATE VIDEO !

21 Surface area Molecules collide with the surface of the solid Extra surface for molecules to collide with. Reactions of solids can only take place at the surface of the solid. If we break a solid into smaller pieces we get a larger surface area and a faster reaction. Smaller particles  larger surface area  more collisions  faster reaction

22 If we grind up a solid to a powder we massively increase the surface area. We therefore massively increase the rate of any reaction Very fast Slow Surface area

23 Rates of Reaction Effect of concentration Effect of catalysts Introduction Summary activities Effect of temperature Effect of surface area Contents

24 Enzymes – biological catalyst Watch the catalyst video!

25 Rates of Reaction Effect of concentration Effect of catalysts Introduction Summary activities Effect of temperature Effect of surface area Contents

26 Glossary activation energy – The amount of energy needed for a reaction to begin. adsorption – The formation of a layer of molecules on the surface of a solid. catalyst – A substance that changes the rate of a reaction without being used up. concentration – The amount of particles in a given volume. enzyme – A biological catalyst. rate of reaction – The speed with which a particular chemical reaction progresses.

27 Particles and rates of reaction

28 Anagrams

29 Stages of a reaction

30 Multiple-choice quiz


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