S3 chemistry unit 1 topic 1 0.0 / 5 ? ChemistryRate of reactionNational 5SQA Created by: RobertCreated on: 08-11-14 15:33 4 factors that can affect the rate of a chemical rection Particle size, Concentration, Temperature and Catalyst 1 of 18 Describe the collision theory Before substances can react the particles must collide with each other 2 of 18 What affect does decreasing the particle size have on rate of reaction The substance area will be much greater and there will be a greater chance that particles can collide and react. Therefore more collisions per second 3 of 18 Give an example reaction when changing the particle size can affect the rate of reaction Marble chips and acid experiment 4 of 18 Describe why increasing the concentration results in an increasing in reaction rate There is more particles of solute (solid) particles in a given volume of solvent (liquid). The more particles the higher the concentracion 5 of 18 How does temperature affect reaction rate As the temperature increases, the time taken for the reaction decreases and the rate of reaction increases 6 of 18 What is a catalyst A catalyst is a substance that speeds up a reaction without being changed or used up 7 of 18 What happens to the rate if the time taken for a reaction decreases The rate increases 8 of 18 What is the relationship between time and rate in a chemical reaction the quicker the rate the shorter the reaction time 9 of 18 Name 4 ways that a chemical reaction could be followed to work out how fast the reaction is proceeding volume of gas produce, the Ph solution, the concentration, the colour 10 of 18 What is the formula used to calculate average rate of reaction Average rate = Quantity ÷ time 11 of 18 What is the rate if 5g is lost in 10 seconds Average rate = Quantity ÷ time, 5 ÷ 10 = 0.5gs-1 12 of 18 How can you tell from looking at a graph that the reaction is faster at the beginning Because there has been more collisions at the start the curve/line will go up a higher slope than at the end 13 of 18 How would you recognise the point on a graph when the reaction has just finished the line will go in a straight line 14 of 18 What is the units for a change in mass g 15 of 18 What is the units for a change in volume cm3 16 of 18 What thing do you need to remember when drawing a scatter/line graph Labels, scale, best fit line, use a ruler 17 of 18 What is the rate if 59-49cm3 is lost in 10-20s seconds Average rate = Quantity ÷ time, 59-45÷20-10, 14÷10 = 1.4cm3s-1 18 of 18
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