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Science-Related Homework Help Chemistry Topic started by: davecvil on Oct 8, 2012



Title: How to deal with fractions when balancing chemical equations?
Post by: davecvil on Oct 8, 2012
For example,
___ZnS+___O2---> ___ZnO+____SO2

I already have the answer for that equation, but the only thing of which I don't get is that how do you get rid of the fractions once you get them? Could you please tell me step by step?

(I think it was something like that you have to get rid of the fraction by multiplying everything by the denominator, but I'm not sure because my teacher went too fast).

Thank you!


Title: How to deal with fractions when balancing chemical equations?
Post by: Lesliep93 on Oct 8, 2012
Your on the right track. Multiply all the coefficients (numbers in front of substances) by the denominator of the fraction.

eg. if the coefficients were 3/2, 3, 5/2
multiply all of them by 2 to get...
3, 6, 5

If you have fractions with more than one denominator eg. 3/2, 3, 5/3
you need to find a number that will cancel out both denominators. in this case, it is 6. you will get...
9, 18, 10


Title: How to deal with fractions when balancing chemical equations?
Post by: lesliepeng on Oct 8, 2012
Multiply through by the LCM.

I did not get fractions the way I balanced above, but if I had, that will work. For example if you had 1/3 and 1/2 involved, you'd multiply through by 6. If you have 1/4 and 1/6 you'd multiply by 12.

By the way, the answer to the above is

2 ZnS + 3 O2 ? 2 ZnO + 2 SO2