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Stoichiometry: Introduction Practice Tests

These Grade 10 Science practice tests introduce moles, Avogadro constant, molar mass, particle and mass conversions, balanced-equation mole ratios, limiting reactants, theoretical yield, percent yield, and empirical formulas.

Skills covered

  • Using the mole as a counting unit and applying Avogadro constant to particles and formula units
  • Calculating molar mass from chemical formulas and converting among grams, moles, and particles
  • Reading balanced-equation coefficients as mole ratios and solving introductory reaction-amount problems
  • Identifying limiting and excess reactants and calculating theoretical and percent yield
  • Using composition data to determine empirical and molecular formulas

How to use these practice tests

Write the balanced equation, identify the known and unknown units, and use dimensional analysis. Keep units visible, use molar mass for grams-to-moles conversion, and use coefficients only after the equation is balanced.

For more Grade 10 Science practice, return to the Grade 10 Science category.

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Grade 10 Stoichiometry Introduction Practice Tests

Practice Grade 10 Science questions about moles, Avogadro constant, molar mass, particle and mass conversions, mole ratios, limiting reactants, yield, and empirical formulas.

Choose the best answer. Track units through mole conversions, use balanced-equation ratios, calculate molar mass, and identify limiting or excess reactants.

10 Questions
0/10 Questions0 %
Correct 0
Incorrect 0
Unanswered 10
1. QuestionMultiple choice

How many molecules are in 3.00 mol of CO₂?

Please select an answer first.

Correct answer: A

The correct answer is 1.8066 × 10²⁴ molecules.

  1. Identify the stoichiometric quantity: Determine whether the question asks about moles, particles, molar mass, a mole ratio, yield, or a limiting reactant.
  2. Set up the relationship: Multiply 3.00 mol by 6.022 × 10²³ molecules per mole.
  3. Check the units and result: The correct answer is 1.8066 × 10²⁴ molecules.

Multiply 3.00 mol by 6.022 × 10²³ molecules per mole.

2. QuestionMultiple choice

How many moles are in 3.011 × 10²³ molecules of O₂?

Please select an answer first.

Correct answer: B

The correct answer is 0.500 mol.

  1. Identify the stoichiometric quantity: Determine whether the question asks about moles, particles, molar mass, a mole ratio, yield, or a limiting reactant.
  2. Set up the relationship: Divide the number of molecules by 6.022 × 10²³ molecules per mole.
  3. Check the units and result: The correct answer is 0.500 mol.

Divide the number of molecules by 6.022 × 10²³ molecules per mole.

3. QuestionMultiple choice

How many moles are in 11.0 g of CO₂?

Please select an answer first.

Correct answer: C

The correct answer is 0.250 mol.

  1. Identify the stoichiometric quantity: Determine whether the question asks about moles, particles, molar mass, a mole ratio, yield, or a limiting reactant.
  2. Set up the relationship: Divide 11.0 g by the CO₂ molar mass of 44.0 g/mol.
  3. Check the units and result: The correct answer is 0.250 mol.

Divide 11.0 g by the CO₂ molar mass of 44.0 g/mol.

4. QuestionMultiple choice

What is the mass of 0.250 mol of CaCO₃?

Please select an answer first.

Correct answer: D

The correct answer is 25.0 g.

  1. Identify the stoichiometric quantity: Determine whether the question asks about moles, particles, molar mass, a mole ratio, yield, or a limiting reactant.
  2. Set up the relationship: Multiply 0.250 mol by the CaCO₃ molar mass of about 100.0 g/mol.
  3. Check the units and result: The correct answer is 25.0 g.

Multiply 0.250 mol by the CaCO₃ molar mass of about 100.0 g/mol.

5. QuestionMultiple choice

What is the mass of 2.50 mol of NaCl?

Please select an answer first.

Correct answer: A

The correct answer is 146 g.

  1. Identify the stoichiometric quantity: Determine whether the question asks about moles, particles, molar mass, a mole ratio, yield, or a limiting reactant.
  2. Set up the relationship: Multiply 2.50 mol by 58.5 g/mol to obtain about 146 g.
  3. Check the units and result: The correct answer is 146 g.

Multiply 2.50 mol by 58.5 g/mol to obtain about 146 g.

6. QuestionMultiple choice

How many moles are in 11.0 g of CO₂ if its molar mass is 44.0 g/mol?

Please select an answer first.

Correct answer: B

The correct answer is 0.250 mol.

  1. Identify the stoichiometric quantity: Determine whether the question asks about moles, particles, molar mass, a mole ratio, yield, or a limiting reactant.
  2. Set up the relationship: Moles equal mass divided by molar mass: 11.0 ÷ 44.0 = 0.250 mol.
  3. Check the units and result: The correct answer is 0.250 mol.

Moles equal mass divided by molar mass: 11.0 ÷ 44.0 = 0.250 mol.

7. QuestionMultiple choice

How many moles are represented by 3.011 × 10²³ molecules of O₂?

Please select an answer first.

Correct answer: C

The correct answer is 0.500 mol.

  1. Identify the stoichiometric quantity: Determine whether the question asks about moles, particles, molar mass, a mole ratio, yield, or a limiting reactant.
  2. Set up the relationship: The amount is half of Avogadro constant, so it equals 0.500 mol.
  3. Check the units and result: The correct answer is 0.500 mol.

The amount is half of Avogadro constant, so it equals 0.500 mol.

8. QuestionMultiple choice

How many molecules are in 0.250 mol of CaCO₃ formula units?

Please select an answer first.

Correct answer: D

The correct answer is 1.5055 × 10²³ formula units.

  1. Identify the stoichiometric quantity: Determine whether the question asks about moles, particles, molar mass, a mole ratio, yield, or a limiting reactant.
  2. Set up the relationship: Multiply 0.250 mol by 6.022 × 10²³ formula units per mole.
  3. Check the units and result: The correct answer is 1.5055 × 10²³ formula units.

Multiply 0.250 mol by 6.022 × 10²³ formula units per mole.

9. QuestionMultiple choice

How many moles are in 4.00 g of helium?

Please select an answer first.

Correct answer: A

The correct answer is 1.00 mol.

  1. Identify the stoichiometric quantity: Determine whether the question asks about moles, particles, molar mass, a mole ratio, yield, or a limiting reactant.
  2. Set up the relationship: Helium has a molar mass of about 4.00 g/mol, so 4.00 g is 1.00 mol.
  3. Check the units and result: The correct answer is 1.00 mol.

Helium has a molar mass of about 4.00 g/mol, so 4.00 g is 1.00 mol.

10. QuestionMultiple choice

How many moles are in 12.0 g of carbon?

Please select an answer first.

Correct answer: B

The correct answer is 1.00 mol.

  1. Identify the stoichiometric quantity: Determine whether the question asks about moles, particles, molar mass, a mole ratio, yield, or a limiting reactant.
  2. Set up the relationship: Carbon has a molar mass of about 12.0 g/mol, so 12.0 g is 1.00 mol.
  3. Check the units and result: The correct answer is 1.00 mol.

Carbon has a molar mass of about 12.0 g/mol, so 12.0 g is 1.00 mol.

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