Stoichiometry Exam

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

What is stoichiometry?

Back

Stoichiometry is the calculation of reactants and products in chemical reactions based on the balanced chemical equation.

Front

How do you determine the limiting reactant in a reaction?

Back

To determine the limiting reactant, compare the mole ratio of the reactants used in the reaction to the mole ratio in the balanced equation.

Front

What is the mole ratio in the reaction N2 + 3H2 → 2NH3?

Back

The mole ratio is 1:3:2 for N2:H2:NH3.

Front

How do you calculate the mass of a reactant needed in a reaction?

Back

Use the molar mass of the reactant and the stoichiometric coefficients from the balanced equation to find the required mass.

Front

What is the molar mass of O2?

Back

The molar mass of O2 (oxygen gas) is approximately 32 g/mol.

Front

If 36.1 g of B2H6 is burned, how much O2 is needed?

Back

125.2 g of O2 is needed to burn 36.1 g of B2H6.

Front

What happens when the limiting reactant is used up?

Back

The chemical reaction stops when the limiting reactant is used up, as there are no more reactants available to continue the reaction.

Front

In the reaction C10H8 + 12 O2 → 10 CO2 + 4 H2O, what is the limiting reactant if 12 moles of O2 react with 1.1 moles of C10H8?

Back

Oxygen is the limiting reactant.

Front

How do you calculate the amount of product formed in a reaction?

Back

Use the stoichiometric coefficients from the balanced equation and the amount of the limiting reactant to calculate the amount of product formed.