Prefix Conversion


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AlyssaPeckham1A
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Joined: Fri Sep 29, 2017 7:04 am

Prefix Conversion

Postby AlyssaPeckham1A » Thu Oct 12, 2017 11:32 am

When converting from a prefix such as nm into meters, should the conversion be before or after we solve the problem?

Jessica Lutz 2E
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Re: Prefix Conversion

Postby Jessica Lutz 2E » Thu Oct 12, 2017 11:36 am

I usually make sure to do it before the problem because most of the time throughout the problem you will be doing dimensional analysis with values that are in meters, not nm (such as velocity).

Sophia Kim 1C
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Re: Prefix Conversion

Postby Sophia Kim 1C » Thu Oct 12, 2017 11:44 am

It depends on the problem! When you are calculating, the numbers should have the same prefix so in that case you would do the prefix conversion before the problem. (ex: if you are using the equation M=moles/L and you have to find the missing moles given M and mL of a solution you would need to do prefix conversion before by either changing the M to moles/ml or changing the given mL to L so that the "Liters" would cancel out and you would only be left with moles). Other times you would need to convert the prefix if the answer needs it to be in a specific unit so than you would just convert after you solved the problem (Ex: if a question asks for the nm of a wavelength and your final answer is in m you would need to do a prefix conversion at the end). I hope this makes some sense!!

Mikaila 3E
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Re: Prefix Conversion

Postby Mikaila 3E » Thu Oct 12, 2017 12:25 pm

Sophia brings up a good point. For me, I think it's up to you and how you prefer to see your numbers/units. I tend to convert my units at the beginning so I don't forget to convert them at the end after all the calculations have been made.

Golbarg Rahimi 3k
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Re: Prefix Conversion

Postby Golbarg Rahimi 3k » Thu Oct 12, 2017 4:01 pm

Hi
I tend to convert all the units into SI units or to common chemistry units ( s , m, g) before trying to solve the problem. After the problem has been solved, I convert them back to the desired units in the problem.

MichelleT_1L
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Re: Prefix Conversion

Postby MichelleT_1L » Thu Oct 12, 2017 6:17 pm

It is the easiest to convert first so you don't forget throughout the problem to convert. At the end you can convert back to the units that the question asks for but throughout the problem if there are different units, using meters, seconds, or kilograms is a basic standard unit to use.

Janet Nguyen 2H
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Joined: Fri Sep 29, 2017 7:05 am

Re: Prefix Conversion

Postby Janet Nguyen 2H » Thu Oct 12, 2017 8:46 pm

I would convert in the beginning or right when you are doing the problem. It would be best to have the same units so that they can properly cancel out. Doing so, you will be seeing that you end up with the right units in your answer.

Peri Bingham 1G
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Re: Prefix Conversion

Postby Peri Bingham 1G » Thu Oct 12, 2017 11:14 pm

I prefer to convert my units in the beginning based on the questions and the formulas being used in the question. At the end of the problem, I make sure that my answer is in the proper units which may involve more converting. In this chapter, I tend to see myself doing this a lot in regards to wavelength and the conversion between nm and m.

Jasmin Tran 1J
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Joined: Thu Jul 27, 2017 3:00 am

Re: Prefix Conversion

Postby Jasmin Tran 1J » Thu Oct 12, 2017 11:57 pm

Like the posters above, I normally convert after or as I'm doing the problem. Say I'm starting with 5.5 kg of Al, I would convert to g or whatever units the question is asking for first so that I don't get confused at the end. Plus, it makes the work neater if you have it with dimensional analysis.

Angel Ni 2K
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Joined: Sat Jul 22, 2017 3:01 am

Re: Prefix Conversion

Postby Angel Ni 2K » Fri Oct 13, 2017 12:46 am

I will usually convert the nm into m first because most ratios use m (such as speed of light). After I finish solving the problem, I make sure that the answer is in the units that the question asks for. If the question does not satisfy, I will usually just leave it in meters.

Hammad Khan 2B
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Re: Prefix Conversion

Postby Hammad Khan 2B » Fri Oct 13, 2017 10:05 am

I would say to convert the problem to whatever the other variables are, so if you have meters in one and nm in another then convert both to meters to solve it and once solved, then put it back into what its asking or meters.

peytonruiz 1H
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Re: Prefix Conversion

Postby peytonruiz 1H » Fri Oct 13, 2017 7:14 pm

I agree. It depends on the problem and the information given. However, usually, I convert before the problem because usually information/constants are given in meters :-)

nanditasundarapandian1D
Posts: 21
Joined: Sat Jul 22, 2017 3:01 am

Re: Prefix Conversion

Postby nanditasundarapandian1D » Fri Oct 13, 2017 8:17 pm

I think it just depends on the specific problem and your preference!


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