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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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1. Test

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

What is a mole in chemistry?

Please select an answer first.

Correct answer: A

The correct answer is A counting unit equal to 6.022 × 10²³ representative particles.

  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: A mole counts a very large number of particles, just as a dozen counts twelve objects.
  3. Check the units and result: The correct answer is A counting unit equal to 6.022 × 10²³ representative particles.

A mole counts a very large number of particles, just as a dozen counts twelve objects.

2. QuestionMultiple choice

What does Avogadro constant represent?

Please select an answer first.

Correct answer: B

The correct answer is 6.022 × 10²³ particles per mole.

  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: Avogadro constant gives the number of representative particles in one mole.
  3. Check the units and result: The correct answer is 6.022 × 10²³ particles per mole.

Avogadro constant gives the number of representative particles in one mole.

3. QuestionMultiple choice

What is molar mass?

Please select an answer first.

Correct answer: C

The correct answer is The mass of one mole of a substance, usually expressed in g/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: Molar mass connects the microscopic amount in moles to a measurable mass.
  3. Check the units and result: The correct answer is The mass of one mole of a substance, usually expressed in g/mol.

Molar mass connects the microscopic amount in moles to a measurable mass.

4. QuestionMultiple choice

Where is an element atomic mass found on the periodic table?

Please select an answer first.

Correct answer: D

The correct answer is Near the element symbol and atomic number as the average atomic mass.

  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 average atomic mass listed on the periodic table is used to calculate molar mass.
  3. Check the units and result: The correct answer is Near the element symbol and atomic number as the average atomic mass.

The average atomic mass listed on the periodic table is used to calculate molar mass.

5. QuestionMultiple choice

How many particles are in 1.00 mol of any substance?

Please select an answer first.

Correct answer: A

The correct answer is 6.022 × 10²³ representative particles.

  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: One mole always contains Avogadro constant representative particles.
  3. Check the units and result: The correct answer is 6.022 × 10²³ representative particles.

One mole always contains Avogadro constant representative particles.

6. QuestionMultiple choice

How many molecules are in 2.00 mol of a molecular substance?

Please select an answer first.

Correct answer: B

The correct answer is 1.2044 × 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 2.00 mol by 6.022 × 10²³ molecules per mole.
  3. Check the units and result: The correct answer is 1.2044 × 10²⁴ molecules.

Multiply 2.00 mol by 6.022 × 10²³ molecules per mole.

7. QuestionMultiple choice

What information is needed to convert grams to moles?

Please select an answer first.

Correct answer: C

The correct answer is The substance molar mass.

  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: Dividing mass by molar mass converts grams into moles.
  3. Check the units and result: The correct answer is The substance molar mass.

Dividing mass by molar mass converts grams into moles.

8. QuestionMultiple choice

How many formula units are in 0.500 mol of an ionic compound?

Please select an answer first.

Correct answer: D

The correct answer is 3.011 × 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 0.500 mol by 6.022 × 10²³ formula units per mole.
  3. Check the units and result: The correct answer is 3.011 × 10²³ formula units.

Multiply 0.500 mol by 6.022 × 10²³ formula units per mole.

9. QuestionMultiple choice

What is the approximate molar mass of H₂O?

Please select an answer first.

Correct answer: A

The correct answer is 18.0 g/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: Two hydrogen atoms contribute about 2.0 g/mol and oxygen contributes about 16.0 g/mol.
  3. Check the units and result: The correct answer is 18.0 g/mol.

Two hydrogen atoms contribute about 2.0 g/mol and oxygen contributes about 16.0 g/mol.

10. QuestionMultiple choice

What relationship does a balanced chemical equation provide for stoichiometry?

Please select an answer first.

Correct answer: B

The correct answer is A mole ratio between reactants and products.

  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: Coefficients in a balanced equation establish the mole relationships used in calculations.
  3. Check the units and result: The correct answer is A mole ratio between reactants and products.

Coefficients in a balanced equation establish the mole relationships used in calculations.

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