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Balancing equations with fractions

Posted: Sat Apr 07, 2018 5:07 pm
by Alondra Juarez section 1E
Balancing equations can be quite confusing when fractions get involved for me. For example for the chemical equation NH3+O2--------->NO+H2O I balanced it and obtained the answer 2NH3+(5/2) O(2)-------->2NO+3H2O, could I leave the fraction or would I have to multiply the whole equation by two in order to get rid of the fraction?

Re: Balancing equations with fractions  [ENDORSED]

Posted: Sat Apr 07, 2018 6:07 pm
by Sunjum Singh 1I
Normally having a fraction isn't ideal, but you're right about multiplying the whole equation by 2 in order to cancel out the fraction and make everything whole numbers. So it would become 4NH3+5O(2)---->4NO+6H20 I believe.

Re: Balancing equations with fractions

Posted: Sat Apr 07, 2018 7:40 pm
by Emma Leshan 1B
Definitely multiply the whole thing by 2. Dr Lavelle said in class that stoichiometric coefficients should be whole numbers.

Re: Balancing equations with fractions

Posted: Sun Apr 08, 2018 12:58 am
by Alma Flores 1D
Yes, you have to multiply by 2 to cancel out the fraction. The stoichiometric coefficients should be whole numbers, not fractions.

Re: Balancing equations with fractions

Posted: Sun Apr 08, 2018 10:30 am
by Isabella Barkett 1G
Also it is easier to use whole numbers as it would be simpler to decipher the mole ratio between reactants and products.

Re: Balancing equations with fractions

Posted: Sun Apr 08, 2018 3:33 pm
by Amir Akhavan 1E
Stoichiometric coefficients should be whole numbers so therefore you should multiply all coefficients by 2. This would make the equation easier to understand as there would be no messy fractions.

Re: Balancing equations with fractions

Posted: Sun Apr 08, 2018 5:19 pm
by Jade Corpus-Sapida 1G
I think this idea is also similar to when we create the empirical formulas. The idea to keep the stoichiometric coefficients whole numbers. For example, if after dividing the moles of a particular element by the smallest number of moles there is still a fractional number, then you would also multiply it by any number in order to find the closest whole number.

Re: Balancing equations with fractions

Posted: Sun Apr 08, 2018 11:07 pm
by Faisal Alshamaa - 1L
I think it is best to have the coefficients be whole numbers and not fractions. However, it is also important to remember that if you are asked something like how many moles of the other reactant (oxygen) are needed when there are only two moles of ammonia the answer would then be (5/2) or 2.5 .

Re: Balancing equations with fractions

Posted: Wed Apr 11, 2018 2:11 pm
by Paywand Baghal
All stoichiometric coefficients should be whole numbers and in order to cancel out the two, you can multiply the entire equation by 2. By doing this, you must multiply 2 to every single part of the equation and not just the coefficient fraction you are trying to make whole.

Re: Balancing equations with fractions

Posted: Wed Apr 11, 2018 4:19 pm
by Jamie Reniva 1J
Stoichiometric coefficients shouldn't be in fraction form because I think that it would indicate that you have to split an atom in half and that's not possible. It is better if you multiply the whole equation by 2.

Re: Balancing equations with fractions

Posted: Wed Apr 11, 2018 10:15 pm
by YeseniaGomez_1L
The coefficients must be in whole numbers so you would have to multipy the whole equation (both sides, like in a math problem) by 2 to get rid of the fraction.

Re: Balancing equations with fractions

Posted: Thu Apr 12, 2018 12:35 pm
by Elana Weingord 1C
It might be easier to begin with the mole ratios in fractions, but the final answer must be given in whole numbers. Using whole numbers is important because when converting atoms needed etc. it is easiest to use whole numbers in the conversions.

Re: Balancing equations with fractions

Posted: Sun Apr 15, 2018 10:19 pm
by Rummel Requerme 1E
It's bad style (actually, even looked down upon by scholars) to be leaving fractions in the equation. Multiply both sides by whatever number, in this case, the number 2, and leave whole numbers.

Re: Balancing equations with fractions

Posted: Sun Apr 15, 2018 10:22 pm
by Jose Munoz 1D
You could leave it like that, however it would just make your life more difficult going forward, that best thing would be for there to be whole numbers.