BRAINCAKEExample Question - 2
Question: A hydrocarbon contains 85.7% carbon and 14.3% hydrogen by mass. Its relative molecular mass is 42. Find its molecular formula. (Ar: C = 12, H = 1)
Step 1: find the empirical formula. Divide each percentage by the relative atomic mass.
C: 85.7 ÷ 12 = 7.14 H: 14.3 ÷ 1 = 14.3
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Key terms in this lesson
- empirical formula
- The simplest whole number ratio of atoms of each element in a compound.
- molecular formula
- The actual number of atoms of each element in one molecule of a compound.
More in Amount of Substance and Calculations
- Percentage Composition by Mass
- Combustion Analysis
- Molecular Formula
- Example Question - 1
- Example Question - 3
- Example Question - 4
- Avogadro's Law
- Gas Volume Calculation - 1
All 39 lessons in Amount of Substance and Calculations · All Edexcel AS-level Chemistry topics