## Mutiplying by a number

katietietsworth_3c
Posts: 31
Joined: Fri Sep 28, 2018 12:24 am

### Mutiplying by a number

Hi, after dividing by the smallest value how would you know what number to multiply by if more than one of the numbers isn't a whole integer. For example, in the vitamin C example you end up with 1.00C:1.33H:1.00O then multiply them by three to get whole integers but what would you do if you had for example, 8.94C:10.92H:1.00O? How would you know what number to multiply them all by to get whole integers and would it be okay to round or no?

Samantha Chang 2K
Posts: 69
Joined: Fri Sep 28, 2018 12:17 am

### Re: Mutiplying by a number

Empirical formula represents the relative number of atoms in a molecule, so I would just round up to the nearest whole number if it is that close. I would say that 8.94 and 10.92 are close enough to be rounded up. In the problems that we are given, it is usually apparent whether we need to multiply by a certain number(i.e 7.25). In addition, when I am off by around .2, I usually recalculate with more significant figures to make sure.

Andrew Lam 3B
Posts: 30
Joined: Fri Sep 28, 2018 12:24 am

### Re: Mutiplying by a number

If it looks like or is close to a fraction, multiply by its inverse to clear a fraction
(e.g. x.3333 multiply by 3, x.25 multiply by 4, x.2 multiply by 5, x.5 multiply by 2, x.75 multiply by 4/3)

If its close to a whole number, just round up (x.9545 just round to the next number)

Hannah Pham 1D
Posts: 62
Joined: Fri Sep 28, 2018 12:19 am

### Re: Mutiplying by a number

You can multiply it by 100 to get an integer and then divide by the greatest common factor to be super exact, but just rounding it would most likely be better.

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