Compression

[Nidhi Thati 3I]

How can we predict the effect of compression/increasing pressure on equilibrium? Sometimes a question will ask about whether the compression will favor the formation of reactants or products, how do we know which one?

[Anamika Patel 3I]

If a system is compressed, the reaction will shift to the side that has less moles of gas. You would look at the stoichiometric coefficients to determine which side has more moles of gas.

[Lilian Doan 1c]

Like the previous reply said, we use Le chateliers principle and look to which side of the equation has less moles. However, from lecture we have to be mindful that it is because of the concentrations of reactants and products changing from compression.

[Audric Banuelos 1A]

If a system is compressed, that means the volume decreases. Therefore, when the volume decreases, the reaction would shift to the side with less moles.
On the other hand, if the volume of the system increases, there would be a shift to the side with more moles.

[Andrew Greenberg 2D]

Compression is the same as decreasing the volume and increasing the pressure. This causes the reaction to shift towards the side with fewer moles. On the other hand, if you decompress the system you are increasing the volume which decreases the pressure and shifts the system toward the side with more moles.

[Daniel Hong 3F]

Compression is a process of decreasing the volume and increasing the pressure. The reaction shifts towards the reactants or products with fewer moles. If the system is expanded, the volume is increased, and decreased the pressure which means that the system will shift toward the reactants or products with more moles.

[Daniel Hong 3F]

Compression is a process of decreasing the volume and increasing the pressure. The reaction shifts towards the reactants or products with fewer moles. If the system is expanded, the volume is increased, and decreased the pressure which means that the system will shift toward the reactants or products with more moles.

[Jonathan_Yu_2C]

when you increase the pressure, the reaction shifts towards the side with less moles of gas using lechatlier's principle

[Amber1L]

When the pressure is increased there is less volume and therefore the reaction will tend towards the side (reactants or products) that has a smaller number of moles. The number of moles can be identified by stoichiometric coefficients.

[Titania Le [2F]]

In order to answer this type of question, we have to consider the number of gas moles on each side of the equation.

1. Check the number of gas moles for the reactants and the products.
2. Identify which side has less moles of gas.
3. Compressing a system will shift the reaction to the side with less moles.

If the system shifts to the left, it favors the reactants. Shifting to the right would favor the production of products! :)

[Jonathan Shenassa]

Something important to note is that a change in pressure can occur in multiple ways. What is important is the change in volume. If one increases pressure by adding a non-reactive gas (like He), Q would not change because the gas concentrations remain the same. A change in pressure resulting from a change in volume will affect the Q in a scenario where there are different amounts of moles on each side of the equation. It is also dependent on the coefficients of the substances. To calculate the new Q value, find the new molarity of each substance by applying the changed volume. Even if you aren’t given the moles of each substance, you can still find the change in concentrations and see how the Q will shift. Generally, if a container is compressed, the reaction will shift to favor the side with less moles, so that the concentration of products = concentration of reactants.