Converting Before or After?

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Tooba_1A
Posts: 11
Joined: Wed Sep 11, 2019 12:16 am

Converting Before or After?

Postby Tooba_1A » Fri Oct 04, 2019 12:26 am

I was confused about how you would know what unit the final answer should be in, especially when it's something as vague as "Find the mass". In addition to this, do you convert the units before you go about the problem, or after you have already solved it?

ABombino_2J
Posts: 102
Joined: Thu Jul 11, 2019 12:15 am

Re: Converting Before or After?

Postby ABombino_2J » Fri Oct 04, 2019 12:37 am

You can have the final units in whichever unit makes the most sense. For example, you would not want a final mass to be 9.8 x 10^-2 kg because you could just say 98g unless it explicitly asks for kg. As you work the problem, you should use whichever units are easiest to use. Grams are usually easiest because molar masses come in grams per mole, but any SI unit can work. Whether or not it is before or after depends on how difficult it will be to work with that mass.

Jasmine Vallarta 2L
Posts: 102
Joined: Sat Aug 17, 2019 12:18 am

Re: Converting Before or After?

Postby Jasmine Vallarta 2L » Fri Oct 04, 2019 12:41 am

I suggest solving the problem first, which ever way is easiest for you. Then convert the units (if needed) to either fit what's being asked in the question, or if units aren't specified in the question, just convert the units into whatever is easiest to read.

Ashley Fang 2G
Posts: 102
Joined: Fri Aug 30, 2019 12:17 am

Re: Converting Before or After?

Postby Ashley Fang 2G » Fri Oct 04, 2019 12:47 am

Convert the units first if you're going to be canceling them out with other units. You want to make sure that like units cancel out like units.
For example, you would not do 5kg x 1mol/18.02g, you would change the 5kg to 5000g first to make sure you're left with only moles when you cancel out the grams.

However, if all your units are the same and you end up with a very large number such as 500,000 grams, it would probably be preferable to convert to kg instead after you have finished your calculations.

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

Re: Converting Before or After?

Postby AronCainBayot2K » Fri Oct 04, 2019 1:02 am

You should always convert after you've completed all steps necessary. For example if it is asking for volume, evidently the answer should be in some form of liter measurement. In these types of cases, just pay attention to the units given and determine whether you would need it to be in milliliters, liters, etc.
Last edited by AronCainBayot2K on Sun Oct 06, 2019 4:30 pm, edited 1 time in total.

pJimenez3F
Posts: 45
Joined: Wed Sep 18, 2019 12:18 am

Re: Converting Before or After?

Postby pJimenez3F » Fri Oct 04, 2019 2:31 am

if youre doing everything right it should cancel out to the right units at the end :)

Jessica Ramirez 3D
Posts: 5
Joined: Thu Jul 11, 2019 12:17 am

Re: Converting Before or After?

Postby Jessica Ramirez 3D » Fri Oct 04, 2019 2:58 am

I was taught to solve the problem first, and convert after, so that it doesn't become confusing before, or even during, solving for any calculations.

Matt F
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

Re: Converting Before or After?

Postby Matt F » Fri Oct 04, 2019 10:21 am

^To add on to this, I would definitely convert after since it could make your calculations a little wonky if you converting during. Only convert during the calculations if you need units to cancel out (they usually should regardless), so I would suggest waiting until the end.

AmyL_3L
Posts: 50
Joined: Fri Aug 09, 2019 12:17 am

Re: Converting Before or After?

Postby AmyL_3L » Sat Oct 05, 2019 2:47 pm

To avoid confusion, convert after solving the problem. However, if you need to cancel out units then converting during calculations is necessary.

Alexa Hernandez 3k
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Joined: Sat Sep 14, 2019 12:16 am
Been upvoted: 1 time

Re: Converting Before or After?

Postby Alexa Hernandez 3k » Sat Oct 05, 2019 2:48 pm

IF EVERYTHING IS GOING WELL THE DESIRED UNITS SHOULD PERFECTLY CANCEL OUT... IF NOT YOU HAVE A BIT OF A PROBLEM...

Nuoya Jiang
Posts: 99
Joined: Sat Sep 14, 2019 12:17 am

Re: Converting Before or After?

Postby Nuoya Jiang » Sat Oct 05, 2019 3:28 pm

It would be easier and clearer to do all the converting after you solve the question and do the correct the calculations, and if you can cancel the units and cut it to a reasonable/desired unit, the answer would probably be right.


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