FREE RPAL Stoichiometry Questions and Answers

Question 1

What does stoichiometry primarily deal with in a chemical reaction?

Accepted Answer

The quantitative relationships between reactants and products

Answer

Stoichiometry involves calculating the quantities of reactants and products in a chemical reaction based on a balanced chemical equation.

Question 2

In the balanced equation 2H₂ + O₂ → 2H₂O, how many moles of water are produced from 3 moles of oxygen?

Accepted Answer

6 moles

Answer

The balanced equation shows that 1 mole of O₂ produces 2 moles of H₂O. Therefore, 3 moles of O₂ will produce 6 moles of H₂O.

Question 3

What is the mole ratio of aluminum (Al) to aluminum oxide (Al₂O₃) in the reaction 4Al + 3O₂ → 2Al₂O₃?

Accepted Answer

4:2

Answer

The balanced equation shows a mole ratio of 4 moles of Al to 2 moles of Al₂O₃, which simplifies to a ratio of 2:1.

Question 4

In the reaction 2Na + Cl₂ → 2NaCl, how many grams of NaCl can be produced from 46 grams of Na (atomic mass of Na = 23 g/mol)?

Accepted Answer

92 grams

Answer

46 grams of Na corresponds to 2 moles (since 23 g/mol * 2 = 46 g). According to the stoichiometry of the reaction, 2 moles of Na produce 2 moles of NaCl, which has a molar mass of 58.5 g/mol. Thus, 2 moles of NaCl weigh 2 * 58.5 g = 117 g.

Question 5

If you have 10 grams of H₂ and 80 grams of O₂, which is the limiting reactant in the reaction 2H₂ + O₂ → 2H₂O?

Accepted Answer

H₂

Answer

10 grams of H₂ corresponds to 5 moles (H₂ has a molar mass of 2 g/mol), and 80 grams of O₂ corresponds to 2.5 moles (O₂ has a molar mass of 32 g/mol). According to the equation, 2 moles of H₂ are required for every 1 mole of O₂, so H₂ is the limiting reactant.

RPAL - Reactants, Products, and Leftovers Practice Test

RPAL - Reactants, Products, and Leftovers Practice Test

FREE RPAL Stoichiometry Questions and Answers