Mass ↔ Moles Calculator
Background
The mole is one of the most important concepts in chemistry. It connects the macroscopic world of grams and liters to the microscopic world of atoms and molecules. The mole allows chemists to count particles by weighing them, since one mole of any substance contains exactly 6.022 × 10²³ particles (Avogadro’s number).
This calculator makes it easy to convert between mass (g), molar mass (g/mol), and moles. Simply enter any two values, and it will compute the missing one. It’s perfect for homework, lab work, or exam preparation.
How to use the calculator
Enter any two of the three values: Mass, Molar Mass, or Moles. Leave the third field blank. Click "Calculate" to find the missing value.
- If you know mass and molar mass → calculate moles
- If you know moles and molar mass → calculate mass
- If you know mass and moles → calculate molar mass
Formula & Equation Used
The fundamental relationship is:
- mass = moles × molar mass
- molar mass = mass ÷ moles
Example Problems & Step-by-Step Solutions
Example 1:
How many moles are in 18 g of water (H₂O), if the molar mass is 18 g/mol?
Solution:
- moles = mass ÷ molar mass
- = 18 ÷ 18
- = 1.00 mol
Example 2:
What is the mass of 0.5 mol of sodium chloride (NaCl), if the molar mass is 58.44 g/mol?
- mass = moles × molar mass
- = 0.5 × 58.44
- = 29.22 g
Example 3:
A student has 12 g of carbon (C) and 1 mol. What is the molar mass?
- molar mass = mass ÷ moles
- = 12 ÷ 1
- = 12 g/mol
Frequently Asked Questions
Q: How do you calculate moles from grams?
Divide the mass of the substance (in grams) by its molar mass (g/mol).
Q: What is molar mass?
Molar mass is the mass of one mole of a substance, usually measured in g/mol. It equals the atomic or molecular weight from the periodic table.
Q: Why are moles important in chemistry?
Moles connect measurable amounts (grams) to the actual number of atoms, molecules, or ions. They are the foundation for stoichiometry and chemical equations.
