Warm-Up: Limiting, Excess Reactant, Percent Yield

Front

What is 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 excess reactant in a chemical reaction?

Back

By comparing the amount of each reactant to the stoichiometric ratio and identifying which reactant is present in excess.

Front

What is the stoichiometric ratio?

Back

The stoichiometric ratio is the ratio of the coefficients of reactants and products in a balanced chemical equation, used to determine the proportions of substances involved in a 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 the theoretical yield?

Back

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

Front

What happens to the excess reactant after a reaction?

Back

The excess reactant remains unreacted after the reaction is complete.

Front

In the reaction 4NH3 + 5O2 → 4NO + 6H2O, which reactant is limiting if 6.30g of NH3 and 1.80g of O2 are used?

Back

To determine the limiting reactant, convert grams to moles and use the stoichiometric ratios from the balanced equation.

Front

If you have 15 moles of X and 10 moles of Y in the reaction 3X + 2Y → 5Z, how do you find the limiting reactant?

Back

Calculate the moles of Z produced from each reactant using stoichiometry; the reactant that produces the least amount of Z is the limiting reactant.

Front

What is the formula for calculating percent yield?

Back

Percent yield = (actual yield / theoretical yield) x 100%.

Front

In a reaction, if 4 moles of A react with 6 moles of B, what is the stoichiometric ratio of A to B?

Back

The stoichiometric ratio of A to B is 4:6, which simplifies to 2:3.