Percentage Yield

Question 1

Define yield

Answer 1

The amount of product you get from a reaction

Question 2

State the formula for percentage yield

Answer 2

actual yield/theoretical yield x 100

Question 3

Define theoretical yield

Answer 3

Mass of product you’d make if all the reactants were converted to products

Question 4

What has happened if a reaction has a low percentage yield?

Answer 4

A lot of reactants have been wasted

Question 5

Why is it important to use reactions with the highest yield possible?

Answer 5

Reduce waste
Keep costs down

Question 6

Explain 3 reasons you won’t get a 100% yield

Answer 6

Incomplete reactions
- not all reactants were converted to product
Practical losses
- you’ll lose some when transferring chemicals between containers
Unwanted reactions
- if unexpected reactions happen, the yield of the intended product goes down. This can be because of impurities in reactions or changes to reaction conditions