DP Chemistry (first assessment 2025)
Question 19M.1A.SL.TZ1.3
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.1A.SL.TZ1.3 |
| Level | SL | Paper | 1A | Time zone | TZ1 |
| Command term | Question number | 3 | Adapted from | N/A |
3.
[Maximum mark: 1]
19M.1A.SL.TZ1.3
What is the empirical formula of a hydrocarbon with 75 % carbon and 25 % hydrogen by mass?
A. C3H
B. CH2
C. C2H6
D. CH4
[1]
Markscheme
D
Examiners report
Well answered and straight forward.
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.