Percentage yield

Question 1

What does percentage yield show?

Answer 1

• It compares theoretical yeild with actual yeild to see how successful a reaction is

Question 2

What is yeild

Answer 2

The amount of product you get from a reaction

Question 3

What is the equation for percentage yeild

Answer 3

Percentage yield =actual yield/theoretical yield x 100

Question 4

Copper oxide reacts with sulfuric acid to make copper sulfate and water. In an experiment, 1.6 g of dry copper sulfate crystals are made. If the theoretical yield is 2.0 g, calculate the percentage yield of copper sulfate.

Answer 4

Actual yield = 1.6 g

Percentage yield = 1.6/2.0 × 100

Percentage yield = 80%

Question 5

Copper oxide reacts with sulfuric acid to make copper sulfate and water. In an experiment, 1.6 g of dry copper sulfate crystals are made. If the theoretical yield is 2.0 g, calculate the percentage yield of copper sulfate.

Answer 5

Actual yield = 1.6 g

Percentage yield = 1.6/2.0 × 100

Percentage yield = 80%

Question 6

Why might it not always be possible to reach 100% percentage ywild

Answer 6

• Some of the product may be lost when it’s separated from its mixture
• some of the reactants may react in different ways than expected

Question 7

Calculate the mass of magnesium sulphate that could be produced from 48g of magnesium assume that the sulphuric acid is unlimited

Answer 7

1. Find number of moles of magnesium -48/24=2 mol
2. To find the mass of magnesium sulphate -2 mol x 120=240g
3. 100% yield because all magnesium reacts to form a product

Question 8

• A dog reactEd 130g of zinc with unlimited copper sulphate
• they produced 24.5g of copper
• calculate the percentage yield

Answer 8

1. Calculate the moles of zinc -130/65=2mol
2. Find the maximum theoretical mass of copper = 2 x63.5=127g copper
3. percentage yeild = actual yield/ theoretical yeild x 100
4. 25.4/127x 100= 20%

Question 9

How to calculate moles

Answer 9

• Number of moles = mass/relative atomic mass