GCSE Chemistry Triple Science

Hi guys,

Can anyone explain Dynamic Equilibrium - Le Chatelier's Principle properly to me please? I don't understand the increasing/decreasing temp, increasing/decreasing gas, and increasing/decreasing concentration at all, like how does it even shift.etc?

Thanks.

Hi guys,

Can anyone explain Dynamic Equilibrium - Le Chatelier's Principle properly to me please? I don't understand the increasing/decreasing temp, increasing/decreasing gas, and increasing/decreasing concentration at all, like how does it even shift.etc?

Thanks.

For concentration I thought of it like this….
Say you have one mole on the left of an equation and two on the right.
As the concentration or pressure increases, the particles all get squished together more.
As the right has more particles, they are more squished so equilibrium moves to the left so less products on the right are made so it’s less squished.
Equilibrium it self isn’t a physical thing that can move. It’s more just that the direction of the reaction changes.
Hope that helps a bit

I’ll try to explain, sorry if you don’t understand me because I might accidentally go into an A level explanation lol.

Temperature:

So say the forward version of the reversible reaction is exothermic (that means it releases heat energy into the surroundings). So that means the reverse reaction will be endothermic (it takes heat energy from the surroundings and feels cold). If you increase the temperature, the position of equilibrium will shift to the left so that the reverse reaction happens more to lower the temperature back to what it was before.
If you decrease temperature then the position of equilibrium shifts to the right so the forward (exothermic) reaction happens more, releasing more heat and increasing the temperature.

Gas pressure:

Example equilibrium system: N2(g) + 3H2(g) <-> 2NH3(g)
In that reaction there are 4 molecules of gas on the left and 2 on the right. If you increase the pressure, the position of equilibrium shifts to the right to make more NH3 so that there are less molecules of gas, because less molecules of gas means a lower pressure. If you decrease pressure then position of equilibrium shifts to the left to make more N2 and H2 to increase the pressure.

Concentration:

Consider the reaction I gave before. If you add more N2 (increasing the concentration) the position of equilibrium shifts to the right to make more NH3 to use up the N2 that you added. Or if you decreased concentration of N2, position of equilibrium shifts to the left to make more and increase the concentration.
If you add more NH3, position of equilibrium shifts to the left to use up the NH3 you added, and if you decrease concentration of NH3, then position of equilibrium shifts to the right to make more.

Le Chatelier’s principle is basically like the position of equilibrium shifting to try and revert any changes that are made to the system. Shifting of the position of equilibrium just means which direction the reversible reaction is going in the most.