Limiting Reactants and Percent Yield Practice

Front

What is a limiting reactant?

Back

The limiting reactant is the substance that is completely consumed in a chemical reaction, limiting the amount of product that can be formed.

Front

How do you identify the limiting reactant in a reaction?

Back

To identify the limiting reactant, calculate the moles of each reactant and determine which one produces the least amount of product based on the stoichiometry of the reaction.

Front

What is percent yield?

Back

Percent yield is a measure of the efficiency of a reaction, calculated as (actual yield / theoretical yield) x 100%.

Front

How do you calculate theoretical yield?

Back

Theoretical yield is calculated based on the stoichiometry of the balanced chemical equation and the amount of limiting reactant.

Front

What is the balanced equation for the combustion of propane (C3H8)?

Back

C3H8 + 5O2 → 3CO2 + 4H2O.

Front

If 3.0g of propane is burned, how do you find the mass of CO2 produced?

Back

Convert grams of propane to moles, use the stoichiometry of the balanced equation to find moles of CO2, then convert moles of CO2 back to grams.

Front

What is the formula for calculating percent yield?

Back

Percent Yield = (Actual Yield / Theoretical Yield) x 100%.

Front

In the reaction P4 + 6Cl2 → 4PCl3, what is the theoretical yield of PCl3 if 75.0g of P4 is used?

Back

First, convert grams of P4 to moles, then use the stoichiometry of the reaction to find moles of PCl3 produced, and convert back to grams.

Front

What is the significance of excess reactants in a chemical reaction?

Back

Excess reactants are those that are not completely consumed in the reaction, allowing the limiting reactant to dictate the amount of product formed.

Front

How do you determine the actual yield of a reaction?

Back

The actual yield is determined experimentally by measuring the amount of product obtained after the reaction.