Percentage Yield

• What is the term used to describe the amount of product obtained from a chemical reaction?

  Yield
• How can yield be measured in chemistry?

  In grams or moles
• What does the term 'actual yield' refer to?

  The amount of product we actually get when we carry out the reaction
• What does 'theoretical yield' describe?

  The yield we expect to get based on our calculations
• If 2 grams of hydrogen reacts with 16 grams of oxygen, what is the theoretical yield of water?

  18 grams
• Why might the actual yield be less than the theoretical yield?

  There are several reasons, including incomplete reactions, side reactions, and product loss
• What is one reason why reactants might not fully react?

  The reaction could be slow or reach equilibrium
• What is a side reaction?

  A reaction where reactants produce a different product than expected
• In the reaction of nitrogen and hydrogen to make ammonia, why might we not get the expected amount of ammonia?

  Because it is a reversible reaction and some ammonia breaks down
• What is one way product loss can occur during a reaction?

  Gaseous products can escape into the air
• What happens when filtering a solution?

  Some liquid or solid may be left behind on the filter paper or in the beaker
• How do you calculate the percentage yield?

  By dividing the actual yield by the theoretical yield and multiplying by 100
• If the actual yield is 15 grams and the theoretical yield is 18 grams, what is the percentage yield?

  83.3%
• What does a percentage yield of 0% indicate?

  No product was obtained from the reaction
• What does a percentage yield of 100% indicate?

  All predicted products were obtained from the reaction
• What are the common reasons for a lower actual yield compared to theoretical yield?

  • Incomplete reactions (reactants not fully reacted)
  • Side reactions producing unexpected products
  • Loss of product during the process (e.g., gaseous escape, filtering losses)
• How do you calculate the percentage yield from a chemical reaction?

  1. Take the actual yield.
  2. Divide by the theoretical yield.
  3. Multiply by 100 to get the percentage.