Fractions

Moderators: Chem_Mod, Chem_Admin

KSong_1J
Posts: 101
Joined: Thu Jul 11, 2019 12:17 am

Fractions

Postby KSong_1J » Sun Oct 06, 2019 9:10 pm

I know this was kind of addressed in a question someone asked earlier but I just wanted to ask if we would be marked down if we left the stoichiometric coefficient as a fraction? I know different professors prefer different things so I just wanted to clarify to see if it would necessarily be seen as a mistake if we left the fraction instead of multiplying both sides to get rid of it?

Sean1F
Posts: 19
Joined: Sat Sep 07, 2019 12:16 am

Re: Fractions

Postby Sean1F » Sun Oct 06, 2019 9:13 pm

I'm guessing it's always best to make the fraction into an integer. I've heard that that is the way it's done in the scientific field and that it is preferred by many since it is more user friendly for future calculations.

Anna Heckler 2C
Posts: 102
Joined: Wed Sep 18, 2019 12:18 am

Re: Fractions

Postby Anna Heckler 2C » Sun Oct 06, 2019 9:41 pm

In past chemistry classes, we have converted the fraction to a decimal and rounded to the correct number of sig figs. I assume Lavelle will prefer we do this since that is typically how figures are reported on lab reports and other experimental documents.

AveryAgosto
Posts: 76
Joined: Wed Sep 18, 2019 12:16 am

Re: Fractions

Postby AveryAgosto » Sun Oct 06, 2019 11:07 pm

I would assume changing the fraction to an integer is the only way you would get full credit. The purpose of making a fraction is so that it's easy to convert all of the elements coefficients to whole numbers.

Ethan Lam 4A
Posts: 69
Joined: Thu Jul 11, 2019 12:17 am

Re: Fractions

Postby Ethan Lam 4A » Mon Oct 07, 2019 11:42 pm

They might give you partial credit though even if you leave it in fractions as long as you show your work.

Sam McNeill 1E
Posts: 110
Joined: Sat Aug 24, 2019 12:17 am

Re: Fractions

Postby Sam McNeill 1E » Tue Oct 08, 2019 12:13 pm

I would change the fraction to an integer since the equation is supposed to represent the exact reaction with the smallest whole integers, not a fraction of it.

TimVintsDis4L
Posts: 104
Joined: Sat Aug 17, 2019 12:17 am

Re: Fractions

Postby TimVintsDis4L » Tue Oct 08, 2019 12:33 pm

I would personally refrain from keeping fractions in the formula because of how easy of a fix it is. All you really have to do is multiply everything by the denominator to remove the fraction. It's an easy fix for something you won't have to worry about later.

Victoria Otuya 4F
Posts: 50
Joined: Wed Sep 18, 2019 12:21 am

Re: Fractions

Postby Victoria Otuya 4F » Wed Oct 09, 2019 1:01 am

Dr.Lavelle states it's better that the fractions are left in whole numbers when balancing equations. Since he prefers it that way, I think it is better to keep the habit of doing it often when it comes down to fractions in a chemical equation.

TarynD_1I
Posts: 100
Joined: Sat Aug 24, 2019 12:17 am

Re: Fractions

Postby TarynD_1I » Wed Oct 09, 2019 2:52 pm

You should multiply all coefficients to make them whole integers, especially if the question is asking for a molecular or empirical formula.

Matthew Tsai 2H
Posts: 101
Joined: Wed Sep 18, 2019 12:20 am

Re: Fractions

Postby Matthew Tsai 2H » Wed Oct 09, 2019 6:24 pm

It's generally good practice to convert all the coefficients to integers, as that gives the most accurate representation of the chemical reaction.

Arvind 4G
Posts: 51
Joined: Thu Jul 11, 2019 12:17 am
Been upvoted: 1 time

Re: Fractions

Postby Arvind 4G » Thu Oct 10, 2019 10:56 am

I would convert all fractions into an integer but using fractions is a good way to keep the numbers straight and helps initially with balancing.

Ashley Kumar 3F
Posts: 50
Joined: Sat Sep 07, 2019 12:18 am

Re: Fractions

Postby Ashley Kumar 3F » Thu Oct 10, 2019 11:44 am

I would say convert it to an integer

Audrie Chan-3B
Posts: 50
Joined: Thu Jul 25, 2019 12:17 am

Re: Fractions

Postby Audrie Chan-3B » Thu Oct 10, 2019 12:36 pm

I think it's best to just multiply it so that it becomes a whole integer.

Juana Abana 1G
Posts: 100
Joined: Wed Sep 18, 2019 12:15 am

Re: Fractions

Postby Juana Abana 1G » Fri Oct 11, 2019 8:46 am

I think it would be better to multiply the faction in order to get an integer.

PriscillaLi_3G
Posts: 63
Joined: Fri Sep 27, 2019 12:30 am

Re: Fractions

Postby PriscillaLi_3G » Fri Oct 11, 2019 11:30 am

Don't leave the coefficients as fractions.

BSolano_3A
Posts: 7
Joined: Tue Nov 13, 2018 12:18 am

Re: Fractions

Postby BSolano_3A » Fri Oct 11, 2019 12:12 pm

The coefficients should always be whole numbers even at their empirical formula notation. Just make them whole numbers, if anything at least at that point you would have gotten your molecular formula. Hope this helps.

Charysa Santos 4G
Posts: 107
Joined: Wed Sep 18, 2019 12:21 am

Re: Fractions

Postby Charysa Santos 4G » Fri Oct 11, 2019 1:08 pm

I remember Prof. Lavelle suggesting that we should convert the fractional stoichiometric coefficients into whole integers.

ThomasNguyen_Dis1H
Posts: 102
Joined: Fri Aug 30, 2019 12:17 am

Re: Fractions

Postby ThomasNguyen_Dis1H » Fri Oct 11, 2019 1:12 pm

It should always be expressed as a whole number. However, during the thermodynamics units, it would be beneficial to leave it as a fraction, but for now just express them as whole numbers.

annikaying
Posts: 94
Joined: Sat Sep 14, 2019 12:16 am

Re: Fractions

Postby annikaying » Wed Nov 13, 2019 5:14 pm

I would convert it to an integer as the TAs always change it and they are the ones that grade the tests and homework.

705198479
Posts: 55
Joined: Wed Sep 18, 2019 12:20 am

Re: Fractions

Postby 705198479 » Wed Nov 13, 2019 5:24 pm

I would always change it to an integer because it gives an accurate answer

RBergtraun_3A
Posts: 41
Joined: Wed Feb 20, 2019 12:15 am

Re: Fractions

Postby RBergtraun_3A » Sun Nov 17, 2019 10:38 pm

its useful to use fractions in the process of figuring it out then multiplying the whole equation (both sides) by a least common denominator.

Nhu Pham-Dis3G
Posts: 45
Joined: Wed Feb 26, 2020 12:15 am

Re: Fractions

Postby Nhu Pham-Dis3G » Tue Oct 06, 2020 6:21 pm

My best guess is just to turn the fractions into whole numbers just to be safe, because in the lecture the professor did mention that stoichiometric coefficients should not be fractions, but ultimately I think it just depends on if the question specifies otherwise.

Kelly Yun 3K
Posts: 54
Joined: Wed Sep 30, 2020 10:03 pm

Re: Fractions

Postby Kelly Yun 3K » Wed Oct 07, 2020 1:35 am

I definitely agree that stoichiometric coefficients should be integers, but would there be a case where the question would tell us to leave it as a fraction?

Lorraine Jiang 3C
Posts: 47
Joined: Wed Sep 30, 2020 9:54 pm

Re: Fractions

Postby Lorraine Jiang 3C » Wed Oct 07, 2020 2:01 am

I think in most cases we should always leave the Stoichiometric coefficients in integers, for example, in the butane combustion class example, professor Lavelle multiplied by all stoichiometric coefficients by 2 in order to have every coefficient as an integer. Unless the question specifically says "leave the stoichiometric coefficient in fraction form" (which I think is not very common), then we leave them in fractions.

Hope it helps!

ShinwooKim_3E
Posts: 40
Joined: Wed Sep 30, 2020 10:00 pm

Re: Fractions

Postby ShinwooKim_3E » Wed Oct 07, 2020 4:46 pm

KSong_1J wrote:I know this was kind of addressed in a question someone asked earlier but I just wanted to ask if we would be marked down if we left the stoichiometric coefficient as a fraction? I know different professors prefer different things so I just wanted to clarify to see if it would necessarily be seen as a mistake if we left the fraction instead of multiplying both sides to get rid of it?

I think it's a stated rule never to have fractions as stoichiometric coefficients when balancing chemical reactions! (Or it's highly recommended to put them as whole numbers)

Mohamed Mido
Posts: 56
Joined: Wed Sep 30, 2020 9:33 pm

Re: Fractions

Postby Mohamed Mido » Wed Oct 07, 2020 4:51 pm

It is technically correct if you leave the coefficients as fractions but it will generally make your math much easier if you try to simplify and have whole numbers.

AlbertGu_3G
Posts: 40
Joined: Wed Sep 30, 2020 9:34 pm

Re: Fractions

Postby AlbertGu_3G » Wed Oct 07, 2020 5:48 pm

I think in one of the modules Prof. Lavelle specifically states that you need to simplify out fraction stoichiometric ratios. Hope this helps!

Eunice_Castro_1G
Posts: 76
Joined: Wed Sep 30, 2020 9:46 pm

Re: Fractions

Postby Eunice_Castro_1G » Wed Oct 07, 2020 6:24 pm

Hello! I think it is preferred to have stoichiometric coefficients as whole numbers, since Dr. Lavelle mentioned how to do it.

Jonathan Batac - 1K
Posts: 45
Joined: Wed Sep 30, 2020 10:03 pm

Re: Fractions

Postby Jonathan Batac - 1K » Wed Oct 07, 2020 7:43 pm

While using fractions when balancing out chemical equations is totally fine and in many cases useful/easier, it is always best to convert it into an integer.

Mingzi Yang 1H
Posts: 40
Joined: Wed Sep 30, 2020 9:53 pm

Re: Fractions

Postby Mingzi Yang 1H » Wed Oct 07, 2020 10:10 pm

I think it is fine to have a fraction as the coefficient. But it will be more convenient if the fractions are converted into whole numbers, especially when you need to do further calculations such as finding the molecular formula etc.

Juwon Lim 3N
Posts: 45
Joined: Wed Sep 30, 2020 9:49 pm

Re: Fractions

Postby Juwon Lim 3N » Wed Oct 07, 2020 10:16 pm

I think Professor Lavelle said in a previous lecture that chemists prefer coefficients to be integers instead of fractions. I know it seems bothersome to convert decimals and fractions into integers, but I think the safe bet is to convert them into integers.

Sharon Kim 1A
Posts: 47
Joined: Wed Sep 30, 2020 9:42 pm

Re: Fractions

Postby Sharon Kim 1A » Wed Oct 07, 2020 10:53 pm

To change it to integers, normally wouldn't you multiply the entire equation by the denominator of the coefficient that's not a whole number

Lauren Sarigumba 1K
Posts: 46
Joined: Wed Sep 30, 2020 9:41 pm

Re: Fractions

Postby Lauren Sarigumba 1K » Wed Oct 07, 2020 11:12 pm

I think it is always safe to convert the fractions into integers for the stoichiometric coefficients in a balanced equation. I remember there was this one multiple-choice question in the post-assessment modules for balancing equations, and the correct answer had stoichiometric coefficients with integers rather than with fractions.

Mackenzie Van Valkenburgh 3G
Posts: 43
Joined: Wed Sep 30, 2020 9:36 pm

Re: Fractions

Postby Mackenzie Van Valkenburgh 3G » Thu Oct 08, 2020 12:09 am

I would definitely say to make all your stoichiometric coefficients into integers. I know Dr. Lavelle mentioned to do so in a lecture, and the UA who hosted tonight's Workshop also said to be sure to convert them into whole numbers, so I would put in that extra step just to be safe. You can always ask your TA to double check how they will be grading, though. :)

Violet Kwan 3L
Posts: 54
Joined: Wed Sep 30, 2020 9:55 pm
Been upvoted: 1 time

Re: Fractions

Postby Violet Kwan 3L » Thu Oct 08, 2020 12:33 am

Whenever Dr. Lavelle has done these types of problems, he always makes sure that the final answer is an integer. In his module videos, he specifically showed that the last step in balancing an equation was to multiply by a factor to get an integer.


Return to “Balancing Chemical Reactions”

Who is online

Users browsing this forum: No registered users and 3 guests