Units for Dilution Equation  [ENDORSED]

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EnricoArambulo3H
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Units for Dilution Equation

Postby EnricoArambulo3H » Mon Oct 05, 2020 11:54 am

When using the dilution Equation M1V1=M2V2, do my units for volume have to be in liters, or can I sometimes use milliliters if I'm going to keep units consistent? I often see problems where we are being asked to put our answers in mL, and I was just wondering if we could keep the units.

Steph Du 1H
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Re: Units for Dilution Equation

Postby Steph Du 1H » Mon Oct 05, 2020 11:55 am

I believe they have to be liters because molarity is mol/L and the units have to match. If it asks you to put your answer in mL, I would just convert my final answer in L to mL.

Mina Tadros 3L
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Re: Units for Dilution Equation  [ENDORSED]

Postby Mina Tadros 3L » Mon Oct 05, 2020 11:58 am

For volume, as long as the units remain constant in the initial and final, you can use either mL or L. It does not matter as long as the question does not specify. However, if you are looking for molarity, you will have to convert to L since M = mol/liter.
Last edited by Mina Tadros 3L on Mon Oct 05, 2020 12:02 pm, edited 1 time in total.

Erika Sosa-Cruz 1J
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Re: Units for Dilution Equation

Postby Erika Sosa-Cruz 1J » Mon Oct 05, 2020 12:01 pm

I would give my final answer in liters since it is the most common unit even if the data given is milliliters always convert it at the end unless they specifically specify to give the answer in milliliters.

SamanthaTolentino 3D
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Re: Units for Dilution Equation

Postby SamanthaTolentino 3D » Mon Oct 05, 2020 12:02 pm

Since the units for molarity is mol.L-1 which is in liters, you have to maintain that same unit when using M1V1=M2V2. If the question wants the answer in mL, you can always convert the answer you get to the needed unit.

Cassidy Cheng 1J
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Re: Units for Dilution Equation

Postby Cassidy Cheng 1J » Mon Oct 05, 2020 12:02 pm

As you said, it doesn't matter if you're being consistent with your units. It may sometimes be easier to do your calculations in mL if the numbers in liters are too small, but make sure to convert your final answer to liters if you have to solve for molarity.

Chem_Mod
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Re: Units for Dilution Equation

Postby Chem_Mod » Mon Oct 05, 2020 12:06 pm

For values in the dilution equation, you can use mL or L as long as you keep the units consistent across all values you plug into the equation.

DMaya_2G
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Re: Units for Dilution Equation

Postby DMaya_2G » Mon Oct 05, 2020 1:38 pm

I noticed on the example in today's lecture that he keeps writing mol. L^-1. We can just write mol/L when completing a problem with the M1V1 = M2V2 equation right?

Ke Huang 2G
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Re: Units for Dilution Equation

Postby Ke Huang 2G » Mon Oct 05, 2020 1:50 pm

I think as long as we use same units for V1 and V2 using the equation, it is okay to use ml or units other than L.

Eunice_Castro_1G
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Re: Units for Dilution Equation

Postby Eunice_Castro_1G » Mon Oct 05, 2020 1:51 pm

You should use Litters because molarity's units are in fact mol.L^-1.

Sabine Salvucci 2E
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Re: Units for Dilution Equation

Postby Sabine Salvucci 2E » Mon Oct 05, 2020 1:56 pm

As long as the initial and final units are the same it doesn't matter whether you use mL or L. When you use mL, it's implied that you're basically multiplying both sides of the equation by 1000 to go from L to mL.

Pranav Daggubati 3C
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Re: Units for Dilution Equation

Postby Pranav Daggubati 3C » Mon Oct 05, 2020 2:24 pm

I am pretty sure you can you either milliliters or liters as long as you have the same on both sides. When you calculate for one of the variables, you'll always end up with the right units if you do this because either Molar unit or the Volume unit will cancel out.

Vanessa Perez
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Re: Units for Dilution Equation

Postby Vanessa Perez » Mon Oct 05, 2020 2:31 pm

Quick question: is 0.987(10^-4)L the same as 9.87(10^-3)L??

annabelchen2a
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Re: Units for Dilution Equation

Postby annabelchen2a » Mon Oct 05, 2020 2:40 pm

Vanessa Perez wrote:Quick question: is 0.987(10^-4)L the same as 9.87(10^-3)L??


No, they're not the same:
0.987 * 10^-4 = 0.0000987, while 9.87 * 10^-3 = 0.00987.
The negative exponent tells you how many spaces to the left you move the decimal point.

AdilaAhmed3I
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Re: Units for Dilution Equation

Postby AdilaAhmed3I » Mon Oct 05, 2020 2:42 pm

replying to Vanessa:

No they are not. For the .987x10^-4, it should not be written this way because proper scientific notation would be 9.87x10^-5 because you have to move the decimal point over to the right by one so it would not be the same as 9.87x10^-3.

.987x10^-4 = .0000987

9.87x10^-3 = .00987

Pranav Daggubati 3C
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Re: Units for Dilution Equation

Postby Pranav Daggubati 3C » Mon Oct 05, 2020 3:10 pm

Vanessa Perez wrote:Quick question: is 0.987(10^-4)L the same as 9.87(10^-3)L??

They would be the same if the exponents were reversed:


Simer_Shera_2D
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Re: Units for Dilution Equation

Postby Simer_Shera_2D » Mon Oct 05, 2020 3:13 pm

For M1V1=M2V2, as long as the units are the same on either side (mL on both sides or L on both sides), it should work. The same would not work if you were finding molarity using M=n/V.

505352202
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Re: Units for Dilution Equation

Postby 505352202 » Mon Oct 05, 2020 3:16 pm

DMaya_3C wrote:I noticed on the example in today's lecture that he keeps writing mol. L^-1. We can just write mol/L when completing a problem with the M1V1 = M2V2 equation right?



Yes, you can write it either way. They mean the same thing. It's just different notation.

Charlotte Adams 1A
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Re: Units for Dilution Equation

Postby Charlotte Adams 1A » Mon Oct 05, 2020 3:19 pm

For the example in the lecture about Dilution, Dr. Lavelle converted mL to liters when doing his calculations but then converted his final answer back to mL. Perhaps it is dependent on the question and the quantity of the answer. It would make more sense if you told someone to measure 15 mL of a solution instead of telling them to measure .015 liters.

Gabriel Nitro 1E
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Re: Units for Dilution Equation

Postby Gabriel Nitro 1E » Mon Oct 05, 2020 3:21 pm

Hi,

When using the dilution equation "M1V1 = M2V2" it is ensured to be used with the units of moles (mol) per liters of solution (L) as in "mol/L" for Molarity and liters (L) for Volume. With regards to mL, if the question asks for milliliters (mL) for an answer, be sure to use liters (L) in your calculations and convert to milliliters (1 L = 1,000 mL) at the final step.

Hope this helps! :)

Haochen He 3L
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Re: Units for Dilution Equation

Postby Haochen He 3L » Mon Oct 05, 2020 9:48 pm

I believe the unit doesn't matter if you're just concerning about the calculation. It's ok to use milliliters for volume. However, if you are tring to solve M, the unit should be in liters. (mol/L)

Margaret Xu 3C
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Re: Units for Dilution Equation

Postby Margaret Xu 3C » Mon Oct 05, 2020 11:05 pm

When solving for a dilution problem (MinitialVinitial = MfinalVfinal), it doesn't matter if you use mL or L as long as you keep the units consistent for Vinitial and Vfinal. If you are solving for volume, and the problem specifies that you should use mL or L, then convert to those units. If you are solving for molarity, then the units you use for volume shouldn't matter (as long as the initial and final volume are consistent) because the units will cancel out in the calculations.

Silvi_Lybbert_3A
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Re: Units for Dilution Equation

Postby Silvi_Lybbert_3A » Mon Oct 05, 2020 11:12 pm

Yes, it is ok to use mL in your calculations as long as you stay consistent throughout. Also, an added note is that if you are using the unit liters in your calculations and your final result is a very small number, it is often preferred to switch your final answer into mL...whichever units make the most sense based off of your judgement.

Aria Movassaghi 1A
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Re: Units for Dilution Equation

Postby Aria Movassaghi 1A » Tue Oct 06, 2020 9:54 am

As long a the units are the same on both sides, it doesn't matter. Make sure you give answer in the requested units though!


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