ning com/ibiscms/mod/ibis/view.php?id 5397195 Chla a State University, San Berna
ID: 1045886 • Letter: N
Question
ning com/ibiscms/mod/ibis/view.php?id 5397195 Chla a State University, San Bernardino- CHEM 345-Spring18 NOBLETActivities and Due Dates Gradebook 92.9/1004/13/2018 08:57 PM Print @calaatr Not Set -Perode Table Question 11 of 15 Map Sapling Learning fluoride (F) To aid in the prevention of tooth decay, it is recommended that drinking water contain 1.10 ppm (e) How many grams of Fr must be Number added to a cylindrical water reservoir having a diameter of 9.38 102 m and a depth of 25.54 m? 1.9x 10g F How many grams of sodium NaF, contain this much 4.20x10, | g NaF fluoride? ?Previous ?Ove Up & View Scuton?Check Answer?Next about us careen privacy policy tems of useconacts e to search w8Explanation / Answer
volume of the reservoir = 3.1416 * radius2 * height
volume = 3.1416 * (9.38x102 /2)2 * 25.54
volume = 1.765 x 10 7 m3
change this to ml , multiply by 1000 000
volume = 1.765 x 1013 ml, since density of water is 1 g/ml, the mass of water is 1.765 x 1013 g
mass of F = concentration of F * mass of water
mass of F = (1.1 / 1 x 106 )* 1.765 x 1013 = 1.941 x 107 grams
b) 1 mole of NaF dissociates like
NaF === Na+ + F-
1 mole of NaF produces 1 mole of Fluorine, calculate the moles of Fluorine
atomic weight of fluorine is 19
moles of F = mass of F / atomic weight F = 1.941 x 107 grams / 19 = 1.0218 x 106
calculate the mass of NaF, using the molar mass = 42
mass NaF = moles * molar mass
Mass NaF = 1.0218 x 106 * 42 = 4.29 x 107 grams or 4.3 x 107 grams
Be careful with the significant figures you are allowed to use
*if this answer is helpful dont forget to rate it =)
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.