practicals

• mean rate of reaction=amount of reactant used or amount of product formed/time
• Product or reactant as a gas is measured in..

  cm3
• Product or reactant as a solid is measured in...

  grams (g)
• Time is measured in...

  seconds (s)
• Rate of reactions units are...

  cm3/s

  g/s
• You can record visual changes in a solution if initial solution is transparent and the product is a precipitate which clouds the solution
• You can measure a mark through the solution and measure how long it takes to...

  disappear
• If reactants are coloured and products are colourless you can time how long it takes for the solution to lose or gain it's colour
• Results for precipitation and colour change are very subjective as people may not agree over exact points of colour change
• Measuring speed of a reaction that produces a gas can be caried out using a what?

  mass balance
• In a change of mass practical, as the gas is released, what measurement disappears on the balance?

  mass
• The quicker the reading drops in a change in mass practical, the quicker the what?

  rate of reaction
• What do we use to measure gas given off?

  gas syringe
• the more gas given off during a given time interval, the faster the what?

  reaction
• Magnesium and what acid react to produce H2 gas?

  dilute Hydrochloric acid
• What gas is produced when magnesium reacts with HCL?

  hydrogen gas
• Describe the steps in the magnesiun+hcl reaction practical

  Add set volume of dilute hcl to a conical flask and place on balance

  Add magnesium ribbon and plug flask with cotton wool

  Start stopwatch and record mass on balance in regular intervals

  work out mass lost for each reading and plot on graph

  repeat with different concentrations
• Sodium thiosulfate and HCl produce what?

  a cloudy precipitate
• sodium thiosulfate and hcl are both..

  clear solutions
• describe how sodium thiosulfate and HCL produce a cloudy precipitate

  add dilute sodium thiosulfate into a conical flask and put on piece of paper with black x

  add dilute HCL and start stopwatch

  watch cross disappear and time how long it takes to go completely

  repeat with different concentrations of either reactant
• What does putting cotton wool in the top of a flask in a reaction with a gas product do?


  Allows gas to escape but keeps other products in