Chapter 2.1-2.3 - Reversible reactions and chemical equilibrium / Evaporation of water ✓ Flashcards
Do non-reversible reactions have a HIGH activation energy for both the forward and reverse reactions?
Yes
Do reversible reactions have a HIGH activation energy for both the forward and reverse reactions?
no
In which processes (physical or chemical) would you commonly see reversible reactions and give examples?
In physical processes such as, evaporation, condensation, dissolving, crystalising etc.
Define a close system.
A closed system is where energy can enter or leave the system but not matter. A contained with a lid is an example.
Define an open system
An open system is where both energy and matter can enter and leave the system. An unsealed flask is an example.
In what system (open or closed) is needed for a reversible reaction to reach equilibrium and why
A closed system because a closed system does not allow matter to enter or leave the system which allow equilibrium to be reached.
What happens during evaporation in an open system?
The vapour diffuses into the surroundings, leaving the system, which results in the flask becoming dry.
What happens during evaporation in a closed system?
The vapour is produced but cannot leave. It condenses and returns to the liquid phase within the flask
Why is evaporation and condensation in a closed system a reversible reaction?
Because water evaporates, then condenses, and the cycle continues.
What is dynamic equilibrium?
It is when the forward and reverse reactions occur at the same rate, leading to no observable change in the system.
What is equilibrium vapour pressure?
It is the constant pressure exerted by a vapour in equilibrium with its liquid phase.
How does temperature affect equilibrium vapour pressure?
As temperature increases, equilibrium vapour pressure increases, and vice versa.
What does the position of equilibrium describe in a liquid-vapour system?
The extent to which water is in the vapour phase; higher vapour pressure means equilibrium favours the vapour phase.
How do intermolecular forces affect equilibrium vapour pressure?
Stronger intermolecular forces lower equilibrium vapour pressure, making the vapour phase less favoured.
What happens in a reversible reaction within a closed system?
It reaches equilibrium, where forward and reverse reactions balance each other
