How to calculate Q if not given concentrations

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Andrew F 2L
Posts: 103
Joined: Sat Aug 17, 2019 12:17 am

How to calculate Q if not given concentrations

Postby Andrew F 2L » Thu Jan 09, 2020 6:52 pm

How are we able to calculate the concentration or partial pressure, lets say, midway through a reaction if they aren't given to us to find Q? Is there a formula we can use?

DanielTalebzadehShoushtari2A
Posts: 53
Joined: Fri Aug 02, 2019 12:16 am

Re: How to calculate Q if not given concentrations

Postby DanielTalebzadehShoushtari2A » Thu Jan 09, 2020 7:14 pm

If concentrations are not explicitly given, there will usually be a way to calculate them. You might be given moles (or mass, which can be converted to moles) and a volume. You can find concentration by dividing moles by volume. If you are given gases and their partial pressures are known and the temperature is given, you can use the ideal gas law to calculate n/V which is molarity.

Jielena_Bragasin2G
Posts: 104
Joined: Sat Aug 24, 2019 12:18 am
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Re: How to calculate Q if not given concentrations

Postby Jielena_Bragasin2G » Thu Jan 09, 2020 7:15 pm

Do you have an example of a problem where this is the case?

Ryan Yee 1J
Posts: 101
Joined: Sat Aug 17, 2019 12:16 am

Re: How to calculate Q if not given concentrations

Postby Ryan Yee 1J » Thu Jan 09, 2020 7:20 pm

Every problem should have some method of being able to retrieve the other concentrations. If you aren't explicitly given a concentration, you might be able to use partial pressures in conjunction with moles withe the ideal gas equation. It's honestly just a matter of how much you play with the variables to manipulate them into something that you want.


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