C2(i) - Bonding and Reactions 16.

Percentage Yield.

Percentage yield tells you about the overall success of an experiment. It compares what you think you should get (predicted yield) with what you get in practice (actual yield).

Percentage Yield Compares Actual and Predicted Yield.

The more reactants you start with, the higher the actual yield will be. But the percentage yield doesn't depend on the amount of reactants you started with, it's a percentage.

1) The predicted yield of a reaction can be calculated from the balanced reaction equation.

2) Percentage yield is given by the formula:

Percentage Yield = actual yield (grams) / predicted yield (grams) x 100

3) Percentage yield is always somewhere between 0 and 100%.

4) A 100% percentage yield means that you got all the product you expected to get.

5) A 0% yield means that no reactants were converted into product, i.e. no product at all was made.

Yields Are Always Less Than 100%.

In real life you never get 100% percentage yield. Some product or reactant always gets lost along the way and that goes for…