BRAINCAKEExample Question - 1
Question: An oxide of iron contains 70.0% iron and 30.0% oxygen by mass. Find its empirical formula. (Ar: Fe = 56, O = 16)
Step 1: divide each percentage by the relative atomic mass. Using percentages is the same as taking a 100 g sample, so the numbers are masses in grams.
Fe: 70.0 ÷ 56 = 1.25 O: 30.0 ÷ 16 = 1.875
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Key terms in this lesson
- empirical formula
- The simplest whole number ratio of atoms of each element in a compound.
More in Amount of Substance and Calculations
- Empirical Formula
- Percentage Composition by Mass
- Combustion Analysis
- Molecular Formula
- Example Question - 2
- Example Question - 3
- Example Question - 4
- Avogadro's Law
All 39 lessons in Amount of Substance and Calculations · All Edexcel AS-level Chemistry topics