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Finding the volume of stock solution to dilute

Posted: Mon Oct 08, 2018 8:43 pm
by Katie Frei 1L
Does anyone know if when solving for an initial volume using the formula M(inital)V(inital) = M(final)V(final), would I have to convert the final volume originally given in mL to liters? In other words, when is it necessary to convert mL to liters? Thanks!

Re: Finding the volume of stock solution to dilute

Posted: Mon Oct 08, 2018 8:46 pm
by ChathuriGunasekera1D
Hi! I don't think it really matters, but I tend to convert to liters if the value exceeds the thousands place. So I would convert 3,000 ml to 3 L just to keep it shorter. I think a TA said that it doesn't matter for the test!

Re: Finding the volume of stock solution to dilute

Posted: Tue Oct 09, 2018 10:09 am
by charlotte_jacobs_4I
Hello! I'm don't think it is completely necessary to convert your answers to mL from Liters, but I usually do since there are sometimes other steps to the problem where you are subtracting a volume from a greater volume and in this case they would both need to have matching units.

Re: Finding the volume of stock solution to dilute

Posted: Tue Oct 09, 2018 10:48 am
by Rehan Chinoy 1K
I don't think it matters, I just prefer to keep it in liters because molarity of a solution is moles/liters. But for the M1V1 equation, since you are essentially finding a value using a ratio, whether you choose mL or L does not matter as long as you are consistent and that you specify.

Re: Finding the volume of stock solution to dilute

Posted: Tue Oct 09, 2018 3:07 pm
by AlyssaBei_1F
It does not matter if you use mL or L, but you have to stay consistent throughout the whole problem. I usually just change to liters.

Re: Finding the volume of stock solution to dilute

Posted: Tue Oct 09, 2018 4:57 pm
by Hailey Boehm 2H
I prefer to convert mL to L because Molarity is moles/L, as mentioned above. It is only necessary to convert from mL to L if the problem specifically asks for liters or vice versa. Mr. Lavelle usually specifies in the question, so be sure to always to aware of units in your final answer. Hope this helps.

Re: Finding the volume of stock solution to dilute

Posted: Tue Oct 09, 2018 5:12 pm
by Tinisha 1G
I would suggest always converting to Liters because molarity is moles/liters and the units always have to be consistent!

Re: Finding the volume of stock solution to dilute

Posted: Wed Oct 10, 2018 10:07 am
by Manya Kidambi 3I
Unless the problem specifically states that you need to keep the answer in L or convert it to mL, I wouldn't worry about it. However, since Molarity = moles/liters, it's a good idea to convert in the beginning itself.

Re: Finding the volume of stock solution to dilute

Posted: Thu Oct 11, 2018 10:11 am
by EllaBerry
Like everyone else said, it isn't necessarily required. However, if you ever want to use that volume to find molarity or moles, you would need to convert it into L, so I would say that it is usually best to do so at the beginning of a problem regardless.

Re: Finding the volume of stock solution to dilute

Posted: Thu Oct 11, 2018 12:09 pm
by 305115396
It doesn't matter but make sure that if you are using mL you are using mL for both Vinitial and Vfinal. The reason it doesn't matter whether it is mL or L it is the same ratio.

Re: Finding the volume of stock solution to dilute

Posted: Thu Oct 11, 2018 12:10 pm
by Marwan Masri 3B
You can use either L or mL as long as you are consistent with the units throughout your calculations.

Re: Finding the volume of stock solution to dilute

Posted: Fri Oct 12, 2018 1:37 pm
by Shibhon_Shepard
The standard one for this equation is Liters, but if asked otherwise, you should probably use liters for your volume.

Re: Finding the volume of stock solution to dilute

Posted: Thu Nov 15, 2018 9:32 pm
by 705022748
L or mL is fine, just make sure to have matching units all throughout. It wouldn't hurt to change it at the beginning, since molarity is moles/L.

Re: Finding the volume of stock solution to dilute

Posted: Sun Sep 29, 2019 4:46 pm
by gabbymaraziti
I'd recommend converting to L before you start your calculations, because the formula for finding molarity is [moles of solute (M)]/[volume of solution (L)]. Either way, you'll have to convert to L before finalizing your answer.