DP Chemistry (first assessment 2025)
Question 22M.1A.SL.TZ2.2
| Date | May 2022 | Marks available | [Maximum mark: 1] | Reference code | 22M.1A.SL.TZ2.2 |
| Level | SL | Paper | 1A | Time zone | TZ2 |
| Command term | Determine | Question number | 2 | Adapted from | N/A |
2.
[Maximum mark: 1]
22M.1A.SL.TZ2.2
30 g of an organic compound produces 44 g CO2 and 18 g H2O as the only combustion products. Which of the following is the empirical formula for this compound?
Mr CO2 = 44 Mr H2O = 18
A. CH2
B. CH3
C. CHO
D. CH2O
[1]
Markscheme
D
Examiners report
63% of the candidates determined the empirical formula of the organic compound correctly using the masses of the sample and the combustion products.
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.