Rates of reaction

• What does the rate of chemical reactions refer to?

  The speed with which the reactants get 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?


  Explosions like 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 express the rate of reaction?

  Rate = quantity of reactants used / time or Rate = quantity of products formed / time
• If 180 cm³ of hydrogen is produced in 2 minutes, what is the rate of reaction in cm³ per second?

  1. 5 cm³ per second
• How do you convert 2 minutes into seconds for calculating the rate of reaction?

  By multiplying by 60 to get 120 seconds
• If 3 g of magnesium takes 4 minutes to disappear completely, what is the rate of reaction in g per second?

  0.0125 g per second
• 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 as the reaction progresses?

  The rate starts fast and slows down as reactants are used up
• How can we visualize the rate of a chemical reaction using graphs?

  • Time on the x-axis
  • Mass of reactant remaining or volume of product produced on the y-axis
  • Reactant mass decreases rapidly at first, then slows down
  • Product 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 moles per minute
• What units can be used to express the rate of reaction?

  • Grams per second (g/s)
  • Cubic centimeters per second (cm³/s)
  • Moles per second (mol/s)
  • Decimeters cubed per second (dm³/s)
  • Moles per minute (mol/min)
• What will the next video cover after this one?

  How to calculate the rate of reaction at a particular time