BREAKING NEWS! Near explosion at local Eling Tide Mill The mill machinery at Eling Tide Mill was accidently started up without any grain in it. Without grain the stones can spark which could have caused an explosion. Why do you think a fire could break out so quickly it would explode at a flour mill?

How Surface Area affects the Rate of Reaction L.O: To understand how surface area affects the rate of a reaction

 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

Which would you use? Which has the highest surface area? What happens to the particles when you add the sugar? Sugar Cubes or Granulated?

Predict what you think the effect of surface area will be on the rate of reaction. Sugar Cubes or Granulated? Does magnesium behave in the same way?

PROVE IT! Your task is to prove whether there was really a massive risk of explosion at the flour mill or was it just media hype!  You will be given calcium carbonate with different surface areas to react with acid. You need to see if the theory that surface area increases the rate of reaction is correct.

Investigating the effect of surface area Calcium carbonate + hydrochloric acid  calcium chloride + carbon dioxide + water Method: 1. Put a 0.6g of large marble chips into a conical flask. Measure out 40cm 3 of hydrochloric acid in a measuring cylinder. 2. Fill your trough ¾ full of water and invert a large measuring cylinder of water into it. 3. Have your delivery tube ready underneath the measuring cylinder. 4. Add the acid to the conical flask and quickly put your bung and delivery tube in. 5. Record the volume of gas collected every 30 seconds. Do this until there are no marble chips left (or after 10 mins) 6. Repeat the experiment with small marble chips

Investigating the effect of surface area Calcium carbonate + hydrochloric acid  calcium chloride + carbon dioxide + water First copy out this results table: Time (sec) Volume of gas collected (cm 3 ) Experiment 1 (large chips) Experiment 2 (small chips) Experiment 3 (powder) Etc.

Results and conclusion 1. Plot a graph of volume of gas (in cm 3 ) against time (in seconds). Use the same axis for both small and large chips. Draw smooth curves through the points 2. How did you keep it a fair test? 3. Which chips had the largest surface area? 4. Which chips gave the fastest reaction? How can you tell from the graphs?

Surface area and particle collisions

The effect of surface area on rate

Now write a conclusion to explain your results. Remember to discuss the collision theory (particles need to collide and with enough energy to react. This activation energy is needed to break the bonds in the reactants).