Collision Theory LO: Describe what needs to happen for a chemical reaction to take place (D) Explain the conditions needed for a chemical reaction to take place (C) Investigate the effect of surface area on reaction rate (B) Plan how you would investigate how surface area affects reaction rate (A/A*) Starter Why do iron filings burn in a bunsen flame and an iron bar does not ?

Practical SAFETY – WEAR GOGGLES AT ALL TIMES. SAFETY – REPORT ALL SPILLS AND BREAKAGES. Measure out 1g of marble chips and put into a flask. Add 25cm3 of Hydrochloric acid. Place on a balance and record the mass over time. Repeat this but using powdered marble. All waste chemicals are to go into the bowl NOT DOWN THE SINK.

Conclusion What has changed with the chemical ? Surface area is bigger for the powder. How has this affected the rate of reaction ? The rate of reaction is faster. Write your conclusion. Making the surface area bigger ____________ the rate of reaction.

Collision Theory For a reaction to happen the molecules must… Collide with each other. Be in the correct orientation. Have enough energy to break bonds. To do this you can… Increase temperature Increase concentration Increase pressure Increase surface area Add a catalyst

Changing concentration

Changing Temperature Changing temperature

Changing Surface Area Changing surface area

Graph of your results Mass (g) Time (mins)

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