Rates of Reaction

• What does the rate of chemical reactions refer to?

  The speed at which reactants are turned into products
• Why is it important to measure the rate of a chemical reaction?

  To understand how fast reactants are used up or products are formed
• What is an example of a slow chemical reaction?

  The rusting of iron
• What is an example of a fast chemical reaction?

  The explosion of fireworks
• How can we measure the rate of a reaction?

  By measuring how fast reactants are used up or how fast products are formed
• What are the two equations to calculate the rate of reaction?

  Rate = quantity of reactants used / time or Rate = quantity of products formed / time
• What units are used to measure quantities in the rate of reaction equations?

  Grams or cm³
• If 180 cm³ of hydrogen is produced in 2 minutes, what is the rate of reaction in cm³ per second?

  $1.5 \text{ cm}^3/\text{s}$
• If 3 g of magnesium takes 4 minutes to disappear completely, what is the rate of reaction in g per second?

  $0.0125 \text{ g/s}$
• What do the calculated rates of reaction represent?

  The average or mean rates of reaction throughout the entire reaction
• How does the rate of reaction change over time?

  • Starts fast when reactants are abundant
  • Slows down as reactants are used up
• How can we visualize the rate of reaction on a graph?

  • Time on the x-axis
  • Mass of reactant remaining or volume of product produced on the y-axis
• What happens to the mass of magnesium in a reaction graph?

  The mass starts at 3 g and falls rapidly, then slows down
• What happens to the volume of hydrogen produced in a reaction graph?

  The volume starts at zero and increases quickly, then levels off
• If 0.6 moles of magnesium are used in 2 minutes, what is the rate in moles per minute?

  $0.3 \text{ moles/min}$
• What units can be used to express the rate of reaction?

  • Grams per second
  • cm³ per second
  • Moles per minute
  • Decimetre cubed per second
• What will the next video cover regarding the rate of reaction?

  How to calculate the rate of reaction at a particular time
• What should viewers do if they enjoyed the video?

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