To aid in the prevention of tooth decay, it is recommended that drinking water contains 0.900 ppm fluoride ( a) how many g of f- must be added to a cylindrical water reservoir having a diameter of 3.36x10^2 m and a depth of 21.80 m? b) how many grams of sodium fluoride, naf, contain this much fluoride?

a) 1.740 g of F- must be added to a cylindrical water reservoir

b) Grams of sodium fluoride, NaF, that contain this much fluoride:

3.84 g

Explanation:

Step 1. calculate the volume of the tank:

Volume of cylinder =

,

Here r = radius of the cylinder = d/2

h = depth = 21.80m

= 168 m

Volume =

2.Convert ppm to g/m3 and Solve for mass of F-

Because both ppm and g/m3 are same quantity .

mass of F- required = 1.740 g

3. Apply mole concept to calculate grams of sodium fluoride produced

mass of 1 mole of F2 = 38 g

mass of 1 mole of NaF = 42 g

(from periodic table calculate molar mass)

Here 1 mole of F2 produce = 2 mole of NaF

So,

38 g  of F2 produce = 2 x 42 g of NaF

38 g of F2 produce = 84 g of NaF

1 g of F2 produce = 84/38 g of NaF

1.74 g F2 produce =

1.74 g F2 produce = 3.84 g of NaF

3.84 g of NaF is produced

the earth would become to overheated and everything alive on it will eventually die from overheating. plants will eventually die as well, water will evaporate, and it will be nothing but a hot planet without anything living on it.