8.3 + 8.4 RP

• particles move faster • particles collide more often • more succesfull collisions • particles collide with more energy • increased proportion of particles have energy greater than the activation energy • increases the rate of reaction

• more particles of the reactants moving around in same volume • more likely they will collide • increased frequency of successful collisions

• squashes gas particles more closely together • more particles in given space • more chance they will collide and react • more frequent successful collisions

• Use measuring cylinder to transfer 10 cm 3 of 0.1 mol/dm 3sodium thiosulfate and 40 cm 3 of water into a conical flask. • Using a measuring cylinder, measure out 10 cm 3 of 2.0 mol/dm 3 hydrochloric acid solution. • Place the conical flask on a piece of laminated paper marked with a cross, immediately add the acid, and start the stopwatch. • Observe the cross from above through the solution and stop the stopwatch as soon as the cross can no longer be seen. • Record the time taken for the cross to be obscured • Repeat the experiment twice more, and calculate the mean time taken. • Repeat the experiment increasing the concentration of sodium thiosulfate by incriments of 10g/dm cubed

• Set up the experiment as shown in the diagram • Use a measuring cylinder to measure 50cm3 of hydrochloric acid. Remove the bung and place in conical flask • Weigh out 5g of calcium carbonate, tip the calcium carbonate into the flask, replace bung immediately and start the stopwatch asap. Swirl flask to mix the contents • Record the time taken for each 10cm3 of gas produced until 100cm3 of gas is produced, for each concentration. • Plot a graph of total volume (y axis) against time (x axis). Plot the graph for each concentration on the same axes