9.1/9.2 - Reaction Rates

• rate of reaction

  change of concentration/amount of a reactant or product per unit time
• how can you find rate of reaction?

  measure rate of formation of products or rate of removal of a reactant
• how can you work out rate of reaction from a graph?

  draw a tangent at the point you want then find the gradient
• how do you work out rate of reaction from experimental data?

  amount of product formed or reactant used / time
• how do you find the relative rate of reaction?

  1/time

  works because rate of reaction is proportional to that
• experiments to measure rate of reaction?

  diasppearing cross experiment

  marble chips and HCl

  change in mass experiment
• disappearing cross experiment

  used to investigate effects of temperature or concentration on rate of reaction

  uses thiosulfate ions and hydrogen ions to produce a precipitate of sulfur

  problem: time when cross disappears is subjective
• marble chips and HCl experiment

  used to investigate effects of temperature, concentration or surface area on rate of reaction