Question

The department of health and human services recently recommended the concentration of fluoride in drinking water be limited to 0.7mg/L (the current policy allows for a range of 0.7 to 1.2 mg/L). The concentration of fluoride in natural water depends on The presence of fluoride-containing minerals

9. (7 points) The Department of Health and Human Services recenty recommended oe concentration of fluoride in drinking water be limited to 0.7 mg (the current poley wws t a range of 0.7 to 1.2 mg/L). The concentration of fluoride in natural water depends on the presence of fluoride-containing minerals For example, the mineral fluorite (also called fluorspar) is eentialy Caf A) A. Calculate the concentration (in M) of fluoride in water in contact with an eces o fluorite. The Ksp of Caf, is 4.0x10- Now let's consider the thermodynamics of dissolving Caf, in water: Caf (s)Cao) (aq) CaFs) -1214.6 Ca (ag) -542.96 2F(oq)329.1 86.87 55.2 9.6 B. Calculate the following parameters for the above reaction: 1.ΔΗ. 2. As 4. Keq Does your answer to B4 agree with the Ksp from Question A7 t not, you might want to chedk your work. Is there a temperature at which CaF-(s) will become soluble in water? ie.AG 0) If vo, calculate that temperature. If not, explain why not C.

Answer 1