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chemistry paper 2 - Coggle Diagram

- - - - the collision frequency of reacting particles (how often they collide) with the more collisions, the faster the reaction is e.g. doubling the frequency of collisions doubles the rate
      - the energy transferred during a collision - particles have to collide with enough energy for the collision to be successful
- - - - start by adding a set volume of dilute hydrochloric acid to a conical flask and carefully place on a mass balance. Next, add some magnesium ribbon to the acid and quickly plug the flask with cotton wool.
      - Once that's done, start the stopwatch and record the mass on the balance. take readings of the mass at regular intervals. After that, plot those results in a table and work out the mass lost for each reading, therefore now being able to plot a graph with time(x-axis) and loss of mass (y-axis) on it.
      - repeating this with more concentrated acid solutions, variables such as the amount of magnesium ribbon and the volume of acid used should be kept the same each time - only change the acid's concentration in order to make it a fair test.
    - - these two chemicals are both clear solutions and they react together to form a yellow precipitate of sulfur
      - start this by adding a set solution of dilute sodium thiosulfate to a conical flask and placing the flask on a piece of paper with a black cross on it to then add some dilute HCI and start the stopwatch
      - now watch the black cross disappear through the cloudy sulfur and time how long it takes to go
      - this reaction can be repeated with solutions of either reactant at different concentrations (only change the conc of one reactant at a time though) - the depth of the liquid must also be kept the same each time
      - these results show the effect of increasing concentration of HCI on the rate of reaction, when added on to an excess of sodium thiosulfate
      - the higher the concentration, the quicker the reaction and therefore less time it takes for the mark to disappear
      - with this reaction, you don' t need a set of graphs like before only using a set of readings instead