CAIE A Level Chemistry 9701 · Equilibria
A chemist carries out the reaction between hydrogen and iodine in a sealed flask at 450 °C.
The flask is sealed so that no gas can enter or leave. After some time, the amounts of all three gases become constant.
Describe what is meant by dynamic equilibrium, and explain why a closed system is needed for equilibrium to be established.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.