Rates of reaction

• Explain how increasing concentration of liquids/ surface area of solids/ pressure of gases affects rate of reaction? (2)

  -Increases rate of reaction

  -More frequent collisions
• Why is more gas produced when concentration is increase, but doesn’t change when surface area is increase? (2)


  -Increased concentration= more particles of reactant (so more product is made.)

  -Increasing surface area= same number of particles (mass stays the same)
• Explain how increasing temperature increases rate of reaction (4)

  -(Rate increase because) particles move faster.

  -more frequent collisions

  -more particles have an energy above the activation energy.
• State the steps needed to calculate rate at a specific time from a graph (5)

  -At that specific time: draw a tangent

  -Pick 2 points on the line

  -draw lines down and across to make a triangle

  -Calculate x (width) y (height) for a triangle

  -Gradient= y/x (always divide time)
• State the key points for answering a 6 mark method question on rate (4)

  -state specific amounts of reactants (e.g 1g of solid, 20ml of liquid)

  -when start/stop stopwatch

  -repeat and change the independent

  -control variables