determining which way the reaction is going

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LeAirraBullingor2k
Posts: 77
Joined: Wed Mar 13, 2019 12:15 am

determining which way the reaction is going

Postby LeAirraBullingor2k » Sun Jan 19, 2020 11:30 pm

What are the steps to determining which way the reaction is going? Isn't it just product over reactants and for gases it just P over RT?

Jared_Yuge
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

Re: determining which way the reaction is going

Postby Jared_Yuge » Sun Jan 19, 2020 11:35 pm

For aqueous solutions you need to calculate the Q of the solution currently and compare it to the Kc and then you can tell which way it is going.
Last edited by Jared_Yuge on Sun Jan 19, 2020 11:37 pm, edited 1 time in total.

Jared_Yuge
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

Re: determining which way the reaction is going

Postby Jared_Yuge » Sun Jan 19, 2020 11:37 pm

for example, when Kc>Q, then the reaction shifts to the right

Mulin_Li_2J
Posts: 105
Joined: Sat Aug 17, 2019 12:16 am

Re: determining which way the reaction is going

Postby Mulin_Li_2J » Sun Jan 19, 2020 11:40 pm

So first let's make it clear that under the same temperature, the equilibrium constant stays the same no matter how many reactants or products there are at the beginning, and in the long-run the reaction will reach the equilibrium.

To determine which way the reaction is going to reach equilibrium, we need to calculate reaction quotient Q first, whose equation is [Products]/[Reactants], with powers of each reactant/product being their stochiometric coefficient. Q has the same equation as K, but in calculating Q, you put in current concentrations, and for K, you put in equilibrium concentrations instead.

Second, compare Q with K, if Q>K, the reaction is favoring reactants formation, and if Q<K, the reaction is favoring products formation.

Hope this can help!

Kennedi2J
Posts: 101
Joined: Wed Sep 18, 2019 12:20 am

Re: determining which way the reaction is going

Postby Kennedi2J » Sun Jan 19, 2020 11:41 pm

What is the process for determining which way the reaction is going when we're not dealing with a gas and not a concentration?

jisulee1C
Posts: 149
Joined: Thu Jul 25, 2019 12:17 am

Re: determining which way the reaction is going

Postby jisulee1C » Tue Jan 21, 2020 12:24 am

For gases, the same rule applies except that you would be using partial pressures and the Kp instead of concentrations and Kc when comparing to Q.


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