## M.7

CaminaB_1D
Posts: 63
Joined: Fri Sep 28, 2018 12:16 am

### M.7

can anyone help with M.7 in the sixth edition? I think I am doing something wrong with converting the masses to moles that is preventing me from figuring out the rest of the problem

Chem_Mod
Posts: 18400
Joined: Thu Aug 04, 2011 1:53 pm
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### Re: M.7

It might be helpful if you post the question in particular you are wondering about. In general, if you are struggling with unit conversions, I HIGHLY recommend writing out each unit.

For example: you are given the mass of X in grams, and you want to get to moles of X. To go from grams to moles, we use the molecular weight, which you get from the periodic table. This is given in units of $frac{grams X}{moles X}$. If you want moles X, you know you need to cancel out the unit you have (grams X). The way to do that is to write it like this:

$\frac{given grams X}{1}x\frac{1 mole X}{grams X}$, then you can cancel out the unit "grams X" since it is in both the numerator and denominator. Finally, you are left with moles X, your desired unit.

Hope this helps!