Use this complete mole calculation worksheet to convert between moles, grams, particles, and gas volume at STP. It includes an instant calculator, solved examples, self-check practice questions, and a full long-form study guide to help students master stoichiometry fundamentals.
Choose a conversion type, enter known values, and click calculate. Use scientific notation (example: 3.2e23) when needed.
Solve each item and enter your numeric answer. Then click Check Answers for instant scoring. Tolerance is ±2% unless exact values are required.
| Problem | Your Answer | Expected Unit |
|---|---|---|
| 1) How many moles are in 36.0 g H₂O? (Molar mass = 18.015 g/mol) | mol | |
| 2) Find the mass of 2.50 mol NaCl. (Molar mass = 58.44 g/mol) | g | |
| 3) Convert 3.01 × 10²³ particles of CO₂ to moles. | mol | |
| 4) How many particles are in 0.200 mol of a substance? | particles | |
| 5) Convert 11.2 L of a gas at STP to moles. | mol | |
| 6) What volume at STP is occupied by 0.75 mol gas? | L |
In chemistry, a mole is a counting unit used to describe a large number of particles such as atoms, molecules, or ions. Just as a dozen means 12 objects, one mole means 6.02214076 × 10²³ particles. This number is called Avogadro’s number. Because atoms and molecules are extremely small, chemists need a practical bridge between the microscopic world (particles) and the laboratory world (grams and liters). The mole is that bridge.
If you are using a mole calculation worksheet in class, the main goal is to become fluent in moving between these forms of chemical quantity:
Once you master these conversions, stoichiometry, limiting reagent problems, and chemical yield calculations become much easier.
The most common mole worksheet questions ask you to convert mass into moles or moles into mass. The key quantity is molar mass, measured in g/mol. Molar mass tells you how many grams correspond to one mole of a substance.
Example: Convert 98.0 g H₂SO₄ to moles. Molar mass of H₂SO₄ is about 98.08 g/mol.
moles = 98.0 ÷ 98.08 ≈ 0.999 mol (approximately 1.00 mol)
Example: Find the mass of 0.400 mol CO₂. Molar mass of CO₂ is 44.01 g/mol.
grams = 0.400 × 44.01 = 17.604 g (often rounded to 17.6 g)
Particle conversion questions use Avogadro’s number. These questions usually involve words such as “atoms,” “molecules,” “formula units,” or “particles.”
Example: 1.204 × 10²⁴ molecules of O₂ to moles.
moles = (1.204 × 10²⁴) ÷ (6.02214076 × 10²³) ≈ 2.00 mol
Example: 0.0500 mol Na atoms to atoms count.
particles = 0.0500 × 6.02214076 × 10²³ = 3.011 × 10²² atoms
At standard temperature and pressure (STP), one mole of an ideal gas occupies approximately 22.4 liters. Many worksheet questions use this shortcut to connect volume and moles directly.
Example: Convert 44.8 L O₂ at STP to moles.
moles = 44.8 ÷ 22.4 = 2.00 mol
Example: 0.25 mol N₂ at STP.
volume = 0.25 × 22.4 = 5.60 L
Question: How many molecules are in 9.0 g of water (H₂O)?
Step 1: Convert grams to moles using molar mass 18.015 g/mol.
moles = 9.0 ÷ 18.015 ≈ 0.4996 mol
Step 2: Convert moles to molecules.
molecules = 0.4996 × 6.02214076 × 10²³ ≈ 3.01 × 10²³ molecules
This type of two-step approach appears very often in middle-school advanced science, high school chemistry, AP chemistry, and introductory college chemistry.
Stoichiometry is built on moles. Balanced equations tell you mole ratios, not gram ratios. So before you can solve reaction calculations, you must be comfortable translating grams and particles into moles and back out again. Practicing with a worksheet plus calculator helps build speed and accuracy. Once these core conversions become automatic, you can focus on reaction logic, limiting reagents, and percent yield.
No. A mole is an amount of substance. Molecular weight (or molar mass in chemistry class context) is mass per mole, usually in g/mol.
It converts between moles and number of particles. Multiply moles by Avogadro’s number to get particles, or divide particles by it to get moles.
Use 22.4 L/mol for ideal gas calculations at STP in many introductory problems. If temperature and pressure differ from STP, use the ideal gas law instead.
Use the periodic table: add each element’s atomic mass multiplied by its subscript in the formula (for example, CO₂ = 12.01 + 2×16.00 = 44.01 g/mol).
This page is designed as a complete study resource for mole calculation worksheet practice, chemistry homework, and exam review. You can bookmark it and reuse both the calculator and self-check section for daily drills.