Question

A toothpaste contains 0.242 %% by mass sodium fluoride used to prevent dental caries and 0.31 %% by mass triclosan C12H7Cl3O2C12H7Cl3O2, an antigingivitis agent. One tube contains 119 g of toothpaste. (Figure 1)

How many fluoride ions, F−, are in the tube of toothpaste?

How many grams of sodium ion, Na+, are in 1.80 g of toothpaste?

How many molecules of triclosan are in the tube of toothpaste?

Answer 1

solution : A tooth paste contain 0.242 % Naf ligg xo. 242 g Nat = 0.28798 g Naf . 0.31 ). mass triclosan » 119 x 0.31 g toi closan 100 SC = 0.3689 g triclosan Molecular mass of Naf = 41.98 g/mol Molecular mass of triclosan = 289.54 g/mol ( 412 Hy C1302) mol of Nat contain 620 22 x 10 23 matsoin each. no of mol of NoF a 0.28798 g = 6.8599x10 mol - in toothpaste 44.989/90) Flourise ion in the toothpaste = 6.8599x10 6.022x123 ion flouride ion in the toothpaste = 41. 31x1020 in

(11) No. of sodium ion in 1.80 g of toothpaste we know that tube contain 0.292 %. by mass of Naf ugg of to oth pase contain 0.28798 g Not or lig g of toothpase contain 41.31 x 10 20 & / Nation iso, 1080g of toothpaste conferise 4 1-31 x 10 20 - xl. so g nation. 1199 10.6248 x 1020 Nation 0.3689 g triclosan present in the tube of toothpaste. (C1₂H₂ C/30₂) Molecular mass of G2 HCl32 = 28.9.548 no. of molecules of triclosan = 0.3689 x 6.022 x 10 289.54 molecules = (7.6725 x 102 molecules of triclosan