Edexcel A-Level Chemistry AS 1.6 Experimental Data to Calculate Empirical and Molecular Formulae Questions

Derive empirical formulae from masses or percentages, use empirical and molar mass to deduce molecular formulae, and determine water of crystallisation from mass loss.

Syllabus
First assessment 2019
Course
Chemistry YCH11
Level
AS

Exam points

  • calculate mole ratios from masses or percentages to obtain an empirical formula
  • use empirical formula mass and molar mass to deduce the molecular formula
  • determine water of crystallisation from mass loss or percentage water data

Edexcel A-Level Chemistry AS 1.6 Experimental Data to Calculate Empirical and Molecular Formulae Questions question 1

[Maximum number: 1]

An organic compound contains 53.3\% carbon, 11.1\% hydrogen and 35.6\% oxygen by mass. The molar mass of this compound is 90.0 g mol−190.0 \mathrm{~g} \mathrm{~mol}^{-1}.
[Data: ArH=1.0C=12.0O=16.0A_{\mathrm{r}} \mathrm{H}=1.0 \quad \mathrm{C}=12.0 \quad \mathrm{O}=16.0 ]
What is the empirical formula of the compound?

A

C4H10O\mathrm{C}_{4} \mathrm{H}_{10} \mathrm{O}

B

C4H10O2\mathrm{C}_{4} \mathrm{H}_{10} \mathrm{O}_{2}

C

C4H5O2\mathrm{C}_{4} \mathrm{H}_{5} \mathrm{O}_{2}

D

C2H5O\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{O}

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