Molarity formula

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Kalsuda Lapborisuth 1B
Posts: 27
Joined: Fri Apr 06, 2018 11:03 am

Molarity formula

Postby Kalsuda Lapborisuth 1B » Sun Apr 08, 2018 4:54 pm

I understand the material so far but I wonder if there are situations/problems where the formula MiVi = MfVf cannot be used?

LilianKhosravi_1H
Posts: 32
Joined: Fri Apr 06, 2018 11:03 am

Re: Molarity formula

Postby LilianKhosravi_1H » Sun Apr 08, 2018 5:12 pm

I think as long as you are given three of those things from the formula then you can use it. You might even be given the mole rather than M or V which you can substitute in place of MiVi since n(moles)=MV

Paywand Baghal
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Joined: Fri Apr 06, 2018 11:01 am

Re: Molarity formula

Postby Paywand Baghal » Wed Apr 11, 2018 2:04 pm

Say you're given two known variables and one unknown, for example you need to find the number of atoms and you have the Molarity and volume, you would use n=M/v. So that would be an example of where you can't use MiVi=MfVf

Andre-1H
Posts: 39
Joined: Fri Apr 06, 2018 11:01 am

Re: Molarity formula

Postby Andre-1H » Wed Apr 11, 2018 6:02 pm

That equation basically comes from the fact that in a dilution the amount of moles does not change. It's just a rewritten form of C(molarity)= moles/vol. There could be other questions asking to reorganize the formula to find a different unknown. But for most dilution problems the formula you gave is the go to.

Yixiao Hu 3C
Posts: 45
Joined: Fri Sep 28, 2018 12:19 am

Re: Molarity formula

Postby Yixiao Hu 3C » Sun Oct 07, 2018 11:18 pm

I think you can use if whenever you have all the numbers. mv=mv is available all the time without any contidions:)

Dana Wilks 3I
Posts: 30
Joined: Fri Sep 28, 2018 12:23 am

Re: Molarity formula

Postby Dana Wilks 3I » Sun Oct 07, 2018 11:51 pm

I also had a question regarding the molarity formula. Is there a difference between the MiVi=MfVf formula and the Molarity= moles/volume formula? Isn't the first just derived from the latter?

705192887
Posts: 77
Joined: Fri Sep 28, 2018 12:18 am

Re: Molarity formula

Postby 705192887 » Mon Oct 08, 2018 12:00 am

Yes, the first is essentially derived from the latter. Sometimes you will need to use just the M1V1=M2V2, depending on what is given, but sometimes you will need both to complete the problem.


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