Stoichiometry

What is the limiting reactant in a chemical reaction?

• The reactant that is present in excess.

• The reactant that determines the maximum amount of product formed.

• The reactant that is completely used up first.

• The reactant that is least expensive.

In the hydrogen combustion example, why was hydrogen the limiting reactant?

• Because hydrogen was completely used up first.

• Because hydrogen is heavier than oxygen.

• Because there was more oxygen than hydrogen.

• Because oxygen was leftover after the reaction.

Why do chemists use moles to determine the limiting reactant?

• Because moles are easier to measure than grams.

• Because moles represent the number of atoms or molecules.

• Because moles are larger than atoms.

• Because moles are visible in the laboratory.

What happens to the leftover reactants in a chemical reaction?

• They react with the products to form new compounds.

• They disappear completely.

• They remain unused and stay in their original form.

• They are converted into products.

How is percent yield calculated in a chemical reaction?

• By subtracting the actual yield from the predicted yield.

• By dividing the actual yield by the predicted yield and multiplying by 100%.

• By dividing the predicted yield by the actual yield.

• By adding the actual yield and the predicted yield.