Chemistry A-Level
molar mass
What molar mass means in Chemistry A-Level, as defined for OCR.
Definitions of molar mass
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Reference: OCR
The mass per mole of a substance, found by adding the relative atomic masses of every atom in the formula.
The quantity M that links to mass through n = m ÷ M, with mass in grams and molar mass in g mol⁻¹.
The sum of relative atomic masses in g mol⁻¹, so for water M = 18.0 g mol⁻¹.
Topics that use molar mass
- Amount of substance (OCR A-Level)
Related terms
- amount of substance
- atom economy
- Atom economy and by-products
- Concentration in mol dm⁻³
- Converting between cm³ and dm³
- Converting between moles and number of particles
- Empirical formula
- Empirical formula mass and molecular formula multiplier
Using molar mass in the exam
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