Grams to Moles
Convert between grams and moles using molar mass. Calculate mass, moles, particles, and gas volumes with comprehensive unit support.
Sample Examples
💧 1 Mole of Water
Classic example: 18.015 grams of water equals exactly 1 mole
⚛️ Carbon-12 Standard
12 grams of carbon-12 is the historical mole definition
🧂 1 Teaspoon of Salt
About 6 grams of table salt - how many moles?
💊 Aspirin 325mg
Standard aspirin tablet - calculate moles of active ingredient
🩸 Blood Glucose (100 mg/dL)
Normal blood sugar in 1 dL - how many millimoles?
⚖️ 0.5 mol NaOH
Calculate grams needed for 0.5 mol sodium hydroxide
☕ Caffeine in Coffee
95mg caffeine in a cup of coffee - molecular count
🥇 Gold Wedding Ring
5 grams of pure gold - how many atoms?
Enter Values
⚠️For educational and informational purposes only. Verify with a qualified professional.
What is the Grams to Moles Conversion?
The grams-to-moles conversion is one of the most fundamental calculations in chemistry. It allows you to convert between the mass of a substance (what you can measure on a balance) and the number of moles (which relates directly to the number of particles). This conversion uses the molar mass as the bridge between mass and moles.
The Core Formula
The relationship is elegantly simple: moles = mass ÷ molar mass
n = moles, m = grams, M = g/mol
Why It Matters
Reactions occur between particles, not grams. Converting to moles lets you use stoichiometry.
- Balance chemical equations
- Calculate reaction yields
- Prepare solutions precisely
Molar Mass
The molar mass (g/mol) is the mass of one mole. Find it by adding atomic masses from the periodic table.
Examples:
- H₂O: 18.015 g/mol
- NaCl: 58.44 g/mol
- C₆H₁₂O₆: 180.16 g/mol
How to Convert Between Grams and Moles
The conversion process is straightforward once you know the molar mass. Follow these steps for accurate calculations every time.
📝 Step-by-Step Process
Grams → Moles
- 1Find the molar mass (add atomic masses)
- 2Divide mass by molar mass
- 3Result is in moles
Example: 36.03 g H₂O ÷ 18.015 g/mol = 2.0 mol
Moles → Grams
- 1Find the molar mass
- 2Multiply moles by molar mass
- 3Result is in grams
Example: 0.5 mol NaCl × 58.44 g/mol = 29.22 g
When to Use This Calculator
Lab Work
Weigh out specific amounts of chemicals for reactions and solutions.
Homework
Check your stoichiometry calculations with step-by-step verification.
Pharmaceuticals
Calculate drug dosages and active ingredient amounts.
Common Molar Masses Reference
| Substance | Formula | Molar Mass (g/mol) | Category |
|---|---|---|---|
| Hydrogen gas | H_{2} | 2.016 | Elements |
| Helium | ext{He} | 4.003 | Elements |
| Carbon | C | 12.011 | Elements |
| Nitrogen gas | N_{2} | 28.014 | Elements |
| Oxygen gas | O_{2} | 32 | Elements |
| Sulfur | S | 32.065 | Elements |
| Iron | ext{Fe} | 55.845 | Elements |
| Copper | ext{Cu} | 63.546 | Elements |
| Zinc | ext{Zn} | 65.38 | Elements |
| Silver | ext{Ag} | 107.868 | Elements |
| Gold | ext{Au} | 196.967 | Elements |
| Water | H_{2}O | 18.015 | Compounds |
Key Formula
n = m / M. Moles = mass (g) ÷ molar mass (g/mol).
❓ Frequently Asked Questions
What is Avogadro's number?
6.022 × 10²³ particles per mole. One mole of any substance contains this many atoms, molecules, or formula units.
📚 Official Data Sources
Important Notes
Use IUPAC atomic weights. Molar mass = sum of atomic masses in formula. Gas at STP: 22.711 L/mol.
⚠️ Disclaimer: This calculator uses IUPAC standard atomic weights and NIST reference data for molar mass. For precise work, consult IUPAC, NIST Chemistry WebBook, and CIAAW for atomic weights and isotopic abundances.