M1V1=M2V2

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emaad_3H
Posts: 51
Joined: Thu Jul 11, 2019 12:17 am

M1V1=M2V2

Postby emaad_3H » Sun Oct 06, 2019 6:09 pm

When can you use the equation M1V1=M2V2? Are there certain scenarios where you have to convert to moles in order to solve for dilution problems?

Tauhid Islam- 1H
Posts: 64
Joined: Fri Aug 02, 2019 12:15 am

Re: M1V1=M2V2

Postby Tauhid Islam- 1H » Sun Oct 06, 2019 6:17 pm

M1V1=M2V2 is a concept that means the amount of moles in the solution remains constant whether you are changing the concentration of the solution or the volume of the solution. So by adding water to a solution with a certain morality of a certain molecule or ion, you are increasing the volume of the solution which in turn changes the molarity or concentration of that molecule or ion in the solution. You would typically use this equation for dilution problems.

Andrea_1H
Posts: 50
Joined: Wed Sep 18, 2019 12:18 am

Re: M1V1=M2V2

Postby Andrea_1H » Sun Oct 06, 2019 7:45 pm

You could use this formula in a question like:
If you dilute 300. mL of a 4.00 M solution of CuCl_{2} to 900. mL, what is the new concentration of the solution? (from a step-up session)

First, you'd use your given to figure out what parts of the equation you already have and then just plugging it in.
M1= 4.00 M CuCl_{2}
V1= 300. mL
M2= ?
V2= 900. mL

You would end up getting 4.00 * 300. mL/900. mL = 1.33 M CuCl_{2}

Jenna Ortiguerra 4G
Posts: 50
Joined: Sat Aug 17, 2019 12:18 am

Re: M1V1=M2V2

Postby Jenna Ortiguerra 4G » Fri Oct 11, 2019 10:32 pm

M1= initial molarity
V1= initial volume
M2= final molarity
V2= final volume
M1V1=M2V2 is used to solve for the concentration or volume of the concentrated or dilute solution. Thus, you can use the formula M1V1=M2V2 when you are trying to solve from the initial molarity, initial volume, final molarity, or final volume (if you are given at least three of the following, it is a huge indicator that you should use this formula if you want to find the missing value).

SajaZidan_1K
Posts: 56
Joined: Wed Sep 18, 2019 12:15 am

Re: M1V1=M2V2

Postby SajaZidan_1K » Fri Oct 11, 2019 10:56 pm

During one of the step up sessions, the UA said to use M1V1=M2V2 whenever a dilution is mentioned. However, when you can't identify a dilution is occurring you most likely have to use M= m/v. This may not always be the case, but this is how I would think of it in simplest terms.

saigorijavolu2k
Posts: 108
Joined: Sat Sep 28, 2019 12:15 am

Re: M1V1=M2V2

Postby saigorijavolu2k » Sat Oct 12, 2019 12:41 pm

Molarity is moles/liters. if a question asks you to find moles of a certain substance. Then you could break down M1V1=M2V2 into moles/liters*volume.

emma brinton_3B
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Joined: Fri Aug 09, 2019 12:17 am

Re: M1V1=M2V2

Postby emma brinton_3B » Sat Oct 12, 2019 12:51 pm

you can use this equation when you have 3 of these values and need to find the fourth value. for example if you had M1 and M2 and V1 you could use this equation to find V2.

Rebekah Alfred 1J
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Re: M1V1=M2V2

Postby Rebekah Alfred 1J » Sat Oct 12, 2019 12:55 pm

When I do these type of problems, I often have to convert the units from grams to moles or milliliters to liters. So make sure you pay attention to the units before you start solving the problems using the equations M1V1=M2V2 and Molarity=moles of solute/liters of solution.

Viviana Velasquez
Posts: 97
Joined: Sat Jul 20, 2019 12:15 am

Re: M1V1=M2V2

Postby Viviana Velasquez » Sun Oct 13, 2019 3:55 pm

This equation can be used when you are given any of the three values needed for the completion of the equation. For example if you are asked to find the V1, you will need to have M1, M2, and V2 in order to be able to use this equation.

JTijerina_4A
Posts: 46
Joined: Mon Sep 23, 2019 12:17 am

Re: M1V1=M2V2

Postby JTijerina_4A » Sun Oct 13, 2019 5:59 pm

You may have to convert to moles in a problem that requires the dilution equation if the question is asking for a particular quantity of moles when given a volume of solution of a certain molarity. It is helpful in these situations to remember that molarity of moles over liters.

pmokh14B
Posts: 107
Joined: Sat Aug 17, 2019 12:15 am

Re: M1V1=M2V2

Postby pmokh14B » Sun Oct 13, 2019 6:38 pm

You use this equation during dilution questions. like when you're asked how much of one solution you would need to achieve certain molarity of another volume solution. Anytime you'd be given three of the variables of the equation and asked to find the other.

AronCainBayot2K
Posts: 101
Joined: Fri Aug 30, 2019 12:17 am

Re: M1V1=M2V2

Postby AronCainBayot2K » Sun Oct 13, 2019 6:52 pm

You use M1V1=M2V2 in dilution problems, typically asking for either the concentration or volume in either the initial side or final side of the equation. One to thing to note is to look closely at what the question is asking for. Just because you are given 2 volume measurements and 1 concentration value does not mean you are always using this equation. Ensure that you have concentrations and volumes to work with ensuring that you convert units necessary. For example if grams are given you need to convert them to moles, and if given milliliters, convert to liters.


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