# Question #7400c

##### 1 Answer

Convert to grams per liter, and then use molecular weight of the compound to convert to moles per liter.

#### Explanation:

First you need to convert grams per ml to grams per l.

Normally, to convert ml to l you would divide by 1000 (since there are 1000 ml in a liter, ml is smaller than l).

However, the number of grams *per* liter will be higher than the number of grams per milliliter (since a litre is a larger volume), so to convert from grams per ml to grams per l you **multiply** by 1000.

Now to convert to grams per liter to moles per liter, you need to use the following equation:

moles (mol) = mass (g) / molecular weight (g per mol)

Divide your grams per liter value by the molecular weight of the compound to convert to moles per liter.

**Worked example**

1.2 grams per milliliter NaCl

1200 grams per liter NaCl

Molecular weight NaCl = 58 grams per mol

1200 / 58 = 20.7 moles per liter