DP Chemistry (first assessment 2025)

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Question 21M.1A.SL.TZ1.2

Date	May 2021	Marks available	[Maximum mark: 1]	Reference code	21M.1A.SL.TZ1.2
Level	SL	Paper	1A	Time zone	TZ1
Command term	Solve	Question number	2	Adapted from	N/A

2.

[Maximum mark: 1]

21M.1A.SL.TZ1.2

A sample of a compound contains approximately 24.0 g C, 3.0 g H, and 1.6 g O. What is the empirical formula of the compound?

A. C₂₀H₃₀O

B. C₈₄H₁₀O₆

C. C₂H₃O

D. C₂₄H₃₀O₂

[1]

Markscheme

A

Syllabus sections

Structure 1. Models of the particulate nature of matter » Structure 1.4—Counting particles by mass: The mole » Structure 1.4.4—The empirical formula of a compound gives the simplest ratio of atoms of each element present in that compound. The molecular formula gives the actual number of atoms of each element present in a molecule. Interconvert the percentage composition by mass and the empirical formula. Determine the molecular formula of a compound from its empirical formula and molar mass.