What mass of that reactant remains unreacted
To determine the mass of the reactant that remains unreacted, we need to know the initial mass of the reactant and the extent of the reaction.
The extent of the reaction can be calculated by dividing the actual yield (the amount of product obtained) by the theoretical yield (the amount of product that should have been obtained based on stoichiometry).
Once we know the extent of the reaction, we can calculate the mass of the reactant that has been consumed by subtracting the mass of the product obtained from the initial mass of the reactant.
Let's say the initial mass of the reactant is represented by mass_initial, the actual yield of the product is represented by actual_yield, and the theoretical yield of the product is represented by theoretical_yield. Then, the mass of the reactant that remains unreacted can be calculated using the following formula:
Mass_unreacted = mass_initial - (actual_yield / theoretical_yield) * mass_initial