Molar Mass Examples in Chemistry
Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Molar Mass.
This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Chemistry.
Concept Recap
The mass in grams of exactly one mole of a substance, calculated by summing the atomic masses of all atoms in the chemical formula. Molar mass is the essential conversion factor between measurable mass (grams) and countable quantity (moles).
How much one mole weighs. For elements, it's the number on the periodic table.
Read the full concept explanation →How to Use These Examples
- Read the first worked example with the solution open so the structure is clear.
- Try the practice problems before revealing each solution.
- Use the related concepts and background knowledge badges if you feel stuck.
What to Focus On
Core idea: Molar mass equals the sum of atomic masses in the chemical formula, in grams per mole.
Common stuck point: Molar mass has units (g/mol); atomic mass is a ratio (no units, or 'amu').
Sense of Study hint: When calculating molar mass, work from the chemical formula. First list each element and its subscript. Then look up each element's atomic mass on the periodic table. Finally, multiply each atomic mass by its subscript and sum everything: M = \sum (\text{atomic mass} \times \text{subscript}).
Worked Examples
Example 1
easySolution
- 1 C: 6 \times 12.01 = 72.06\,\text{g/mol}.
- 2 H: 12 \times 1.008 = 12.10\,\text{g/mol}.
- 3 O: 6 \times 16.00 = 96.00\,\text{g/mol}.
- 4 Total: 72.06 + 12.10 + 96.00 = 180.16\,\text{g/mol}.
Answer
Example 2
mediumPractice Problems
Try these problems on your own first, then open the solution to compare your method.
Example 1
easyExample 2
easyRelated Concepts
Background Knowledge
These ideas may be useful before you work through the harder examples.