Theoretical yield: the maximum possible mass of a product that a chemical reaction can make. It is calculated using molar ratios.
Actual yield: the mass of a product that a chemical reaction makes in real life. It is usually less than the theoretical yield, for a number of reasons:
Percentage yield: a comparison between actual yield and theoretical yield.
The percentage yield can vary from 100% (no product lost) to 0% (no product made).
12.4 g of copper(II) carbonate are heated and decomposes. 6 g of copper(II) oxide is formed. Calculate the percentage yield.
CuCO3 → CuO + CO2
Calculate the theoretical yield, using the same steps as a reacting mass calculation.
1 mol CuCO3 : 1 mol CuO
0.1 mol CuCO3 forms 0.1 mol of CuO
Mass of CuO = moles x Mr = 0.1 x 80 = 8g