Final answer:
To calculate the percent yield, divide the actual yield by the theoretical yield and multiply by 100.
Step-by-step explanation:
The percent yield is calculated by dividing the actual yield by the theoretical yield and multiplying by 100. In this case, the actual yield is 0.8 g and the theoretical yield can be calculated by stoichiometry. Let's assume the balanced equation is: A + B → C. If 1.0 g of reactant A produces 0.8 g of product C, then the percent yield is (0.8 g / theoretical yield) x 100. Since the values of the reactant and product masses are not provided, we cannot determine the exact theoretical yield and thus the percent yield cannot be calculated.