Effect of Pressure (contraction) in reaction

[austin-3b]

If there are zero moles on one side of the reaction (solid only) and you compress the system, does the reaction shift to that side or does it not (because the solid does not contribute to equilibrium)?

Example
A(s) --> B (aq) + C (g)

[BrittneyMyint1D]

Hi, from my understanding, if you compress the system, the reaction would shift to the left (based on your equation) since theres less/no moles on the reactants side. Decreasing volume would affect the concentration by increasing the concentration of the products, making Q>K at that instant, so the reaction would want to shift left to return to equilibrium. Hope that makes sense!

[Emma_Barrall_3J]

I agree with Brittney, it would shift to the left as there are less moles of gas on that side.

[Libby Dillon - 1A]

Yes, even though there are no moles of gas on the reactants side of the equation (only solids), the reaction would still shift to the left if there was an increase in pressure do to a decrease in volume. Whichever side has fewer moles of gas is the direction in which the reaction will shift (even 0 moles gas).

[My-Lan Le 1L]

The reaction will still shift to the left because it favors whichever side has less moles when it is compressed. Even if there isn't a gas on the left, I also think that it would still favor the left.

[Emmeline Phu 1G]

Hi! In the case of the example you gave, if we compressed the system, the reaction would shift towards the side with a smaller number of mols to balance out the pressure. Thus, since the reactant side has 0 moles and the product side has 2 moles, the reaction would shift to the left. Hope this helps! :)

[kristinalaudis3e]

during compression, reactions favors the side with the least amount of moles, so in this example it would shift to the left.

[Chinmayi Mutyala 3H]

It would shift to the left since by compressing the system, you are increasing the pressure. The left has less moles of gas. By shifting the equilibrium to the left, more solid reactant would be made and decrease the pressure of the system.

[Hannah Lechtzin 1K]

As mentioned above, the reaction will still shift left because there are no moles of reactant. The reaction will still want to reach equilibrium despite being compressed.