Question

It is recommended that drinking water contain 1.6 ppm fluoride (F−) for prevention of tooth decay. Consider a reservoir with a diameter of 4.70 ✕ 102 m and a depth of 14.2 m. (The volume is πr2h, where r is the radius and h is the height.) How many grams of F− should be added to give 1.6 ppm?

Answer 1

total amount of fluoride 3.6 *10^6 g

Step-by-step explanation:

we know that

volume of reservoir
`= \pi r^2 h`

=
`\pi* [(4.70*10^2)/(2)]^2 *14.2`

= 2.25*10^6 m^3

denso=ity of water = 1000 kg/m3

mass of water = 1000*2.25*10^6

= 2.25*10^9 kg = 2.25*10^12 g

fluoride 1.6 ppm

total amount of fluoride
`= (1.6)/(10^6) * 2.25*10^(12) g`

= 3.6 *10^6 g