Mean Rate of Reaction and Reaction Graphs

• What does the slope of the line on a graph of product quantity against time indicate?

  The slope indicates the rate of reaction; a steeper slope means a faster reaction.
• What happens to the slope of the graph as the reaction progresses?

  The slope becomes less steep, indicating that the reaction is slowing down.
• Why does the reaction slow down over time?

  Because many reactant molecules have already reacted, leaving fewer available to react.
• What does a flat line on the graph indicate?

  That the reaction has stopped because all reactant molecules have reacted.
• How is the quantity of product formed measured if it is a gas?

  In centimeters cubed.
• What are the two ways to measure the rate of a chemical reaction?

  • By measuring the quantity of product formed
  • By measuring the quantity of reactant used
• How do you calculate the mean rate of a reaction?

  The mean rate of reaction equals the quantity of product formed divided by the time taken.
• If 60 grams of product is formed in 15 seconds, what is the mean rate of reaction?

  The mean rate of reaction is 4 grams per second.
• What is the mean rate of reaction if 20 grams of product is formed in 40 seconds?

  The mean rate of reaction is 0.5 grams per second.
• How do you calculate the mean rate of reaction from the quantity of reactant used?

  The mean rate of reaction is the quantity of reactant used divided by the time taken.
• If 30 grams of reactant is used in 10 seconds, what is the mean rate of reaction?

  The mean rate of reaction is 3 grams per second.
• What is the mean rate of reaction if 150 grams of reactant is used in 75 seconds?

  The mean rate of reaction is 2 grams per second.
• How is the slope of the graph related to the rate of reaction?

  The slope of the graph gives an idea of the rate of the reaction
• What happens to the rate of reaction over time according to the video?

  The reaction starts fast, slows down, and eventually stops