Question

you are a public health officer in the water treatment facility for a city of 50,000 people . A concentration of 1.0 ppm of fluoride in the drinking water is sufficient for the purpose of helping to prevent tooth decay. The compund normally chosen for fluoridation is the same as is found in some toothpaste, sodium fluoride, NaF. Calculate how many kilograms of sodium fluoride you will need to purchase in order to fluoridate the city's water supply for one year, based upon your estimate that the average daily consumption of water is is 150 gallons per person.

Answer 1

You want 1 ppm F. That is 1 mg/L F and
1 mg F x (molar mass NaF/atomic mass F) = ? mg NaF/L.

150 gal/person x 50,000 persons = ? gallons/yr
Convert gallons/yr to L/yr.
? mg NaF/L x #L = mg NaF/yr
Then convert mg NaF to kg NaF.

Answer 2

23