Percent Yield and Limiting Reactant

Front

What is the definition of a limiting reactant?

Back

The limiting reactant is the substance that is completely consumed in a chemical reaction, determining the maximum 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 reactant will produce the least amount of product based on the stoichiometry of the reaction.

Front

What is the formula for percent yield?

Back

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

Front

If the theoretical yield of a reaction is 50g and the actual yield is 40g, what is the percent yield?

Back

Percent yield = (40g / 50g) x 100% = 80%.

Front

What does it mean if a reaction has a percent yield of over 100%?

Back

A percent yield over 100% indicates an error in measurement or calculation, as it is impossible to produce more product than theoretically possible.

Front

In the reaction 4NH3 + 5O2 -> 4NO + 6H2O, how do you determine the excess reactant?

Back

Calculate the moles of NH3 and O2 used, determine the limiting reactant, and then subtract the amount consumed from the initial amount to find the excess.

Front

What is the theoretical yield?

Back

The theoretical yield is the maximum amount of product that can be produced from a given amount of reactants, based on stoichiometric calculations.

Front

In a reaction, if 10g of A reacts with 15g of B and produces 5g of product, what is the percent yield if the theoretical yield is 8g?

Back

Percent yield = (5g / 8g) x 100% = 62.5%.

Front

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

Back

The excess reactant is the reactant that remains after the reaction has gone to completion; it indicates how much of that reactant was not needed.

Front

How can you calculate the amount of excess reactant left over?

Back

Subtract the amount of the limiting reactant used from the initial amount of the excess reactant based on the stoichiometry of the balanced equation.