Dimensional analysis and fluoride

[leroyjenkens]

Homework Statement

Nutrition experts recommend that you drink at least 8 cups of water daily. If your local water supply contains 1.00 part fluoride (by mass) per million parts water, how many milligrams of fluoride would you consume daily in your 8 cups of water? (use 1.00 g cm^-3 as the density of water)

Homework Equations

The Attempt at a Solution

I just don't know how to set this up. I tried putting 1.00 part fluoride over 1 million parts water, but that just made a mess. Fluoride is in parts and I have to convert that to milligrams. I'm lost on how to do that.

Thanks.

 

[cepheid]

1 ppm of F by mass just means that for any mass of water, the mass of fluoride present in it will be one millionth that.

So all you have to do is calculate the mass of water present, and then divide that by 10⁶ to get the mass of fluoride in that water.

EDIT: Since the density of water is given in cgs units, you'll have to convert the given volume of water to cgs units.