Change in Pressure

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Ellis Song 4I
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Joined: Thu Jul 11, 2019 12:17 am

Change in Pressure

Postby Ellis Song 4I » Fri Jan 17, 2020 10:21 pm

Can someone explain exactly why the reaction shift is dependent on the number of moles on each side of the reaction?

Jacey Yang 1F
Posts: 101
Joined: Fri Aug 09, 2019 12:17 am

Re: Change in Pressure

Postby Jacey Yang 1F » Fri Jan 17, 2020 10:38 pm

According to Le Chatelier's principle, when the amount of reactant or product is changed in a reaction, the equilibrium will shift to minimize the effect

AKhanna_3H
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Joined: Wed Sep 18, 2019 12:19 am

Re: Change in Pressure

Postby AKhanna_3H » Sat Jan 18, 2020 11:00 am

If more reactants are added (increasing the number of moles), the reaction will "shift right" meaning more products will be formed to offset that change. Now that there are more reactants available, more products must form to keep the reaction in equilibrium. If reactants are removed (decreasing the number of moles), the reaction will "shift left" meaning less products will be formed. You can use similar logic to explain what happens when the number of moles on the products side increases or decreases. Hope that helps!

Sanjana Munagala_1j
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Re: Change in Pressure

Postby Sanjana Munagala_1j » Sat Jan 18, 2020 1:39 pm

Usually when we determine a shift in a reaction by comparing the number of moles on each side of the reaction it is usually when analyzing a change in the reaction given a change in pressure. In such a case, if you increase pressure, a reaction would shift to the side with less moles of gas in order to offset the increase in pressure by reducing the amount of molecules in the defined volume. The opposite situation would also have similar logic. It is important to note that when there is a change in pressure, it really only affects the reaction if there is a corresponding affect on volume, as that relates to changes in concentration.

Hope that helps!

305385703
Posts: 102
Joined: Thu Jul 11, 2019 12:15 am

Re: Change in Pressure

Postby 305385703 » Sat Jan 18, 2020 5:54 pm

There is a natural point where there will the energy will be the lowest for a certain reaction. Some reactions will be at their lowest energy when there are a relatively high number of products, and vice versa. Thus, when there is a change in the number of moles of a reaction, then that reaction will shift to ensure that it is once again at the ratio of products to reactants that is the most stable.

Anika Chakrabarti 1A
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Joined: Sat Aug 24, 2019 12:17 am

Re: Change in Pressure

Postby Anika Chakrabarti 1A » Sat Jan 18, 2020 8:14 pm

When the pressure is increased by decreasing volume, the reaction will move in whichever direction will reduce the pressure. This means that it will move towards the side with fewer moles (so fewer molecules), which causes the pressure to decrease.


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