6-rates of reaction

• whats the aim of the experiment?

  To investigate the effect of changing surface area of marble chips in the reaction between marble chips and hydrochloric acid
• what equipment is needed?

  • Marble chips, small and large
  • Hydrochloric acid 1 mol dm-3 
  • Conical flask (100 cm3)
  • Safety goggles
  • Gas syringe
  • Stop clock
• what is the method?

  • Add hydrochloric acid into a conical flask
  • Use a delivery tube to connect this flask to an inverted measuring cylinder
  • Add marble chips into the conical flask and close the bung
  • Measure the volume of gas produced in a fixed time using the measuring cylinder
  • Repeat with different sizes of marble chips 
• what are the results?

  • Increase in the surface area of the marble chip, the rate of reaction will increase
  • This is because more surface area particles of the marble chips will be exposed to the dilute hydrochloric acid so there will be more frequent and successful collisions, increasing the rate of reaction
• what is the balanced equation?


  $​ CaCO3+$$2HCl→CaCl2+$$H2O+$$CO2$
• What are two different methods of collecting and measuring the volume of gas produced?

  with a gas syringe or upside down measuring cylinder
• how do you decrease the size of marble chips?

  Use a mortar and pestle or a mechanical grinder to crush the marble chips into smaller pieces. This method allows you to control the size of the resulting particles.
• how does the decrease in size of the marble chips affect the surface area of the marble chips?

  Decreasing the size of the marble chips increases the total surface area available for the reaction. This is because smaller chips have a greater combined surface area compared to larger chips.
• how do you calculate rate of reaction?

  reactant used or product formed/time taken
• What needs to be kept the same when you repeat the first experiment but use different size marble chips?

  • concentration of acid
  • volume of acid
  • temperature
• how could you decrease the concentration of the hydrochloric acid?

  diluting it with water
• what effect will decreasing the concentration of hydrochloric acid have on the rate of reaction?


  the rate of reaction will slow down because there are fewer hcl molecules available to collide with the marble chips, less frequent and unsuccessful collisions
• how do you calculate the gradient on a graph?

  product/time