DP Chemistry (first assessment 2025)
Question 22M.1A.SL.TZ2.16
| Date | May 2022 | Marks available | [Maximum mark: 1] | Reference code | 22M.1A.SL.TZ2.16 |
| Level | SL | Paper | 1A | Time zone | TZ2 |
| Command term | State | Question number | 16 | Adapted from | N/A |
16.
[Maximum mark: 1]
22M.1A.SL.TZ2.16
Why does a reaction for a sample of gases, at constant temperature, occur faster at higher pressure?
A. Collisions are more frequent.
B. Collisions are more energetic.
C. High pressure lowers activation energy.
D. The reaction is more exothermic at high pressure.
[1]
Markscheme
A
Examiners report
A very well-answered question in which 90% of the candidates related the effect of higher pressure on the rate of reaction of gaseous reactants to the collision theory correctly.
Syllabus sections
Reactivity 2. How much, how fast and how far? » Reactivity 2.2—How fast? The rate of chemical change » Reactivity 2.2.2—Species react as a result of collisions of sufficient energy and proper orientation. Explain the relationship between the kinetic energy of the particles and the temperature in kelvin, and the role of collision geometry.
Structure 1. Models of the particulate nature of matter » Structure 1.5—Ideal gases » Structure 1.5.1—An ideal gas consists of moving particles with negligible volume and no intermolecular forces. All collisions between particles are considered elastic. Recognize the key assumptions in the ideal gas model.