Question

200 ml of a solution of mgco3 contains 21 g of mgco3 if 25 ml of the solution is diluted to 1250 ml. what is the molarity of resulting solution ?

Answer 1

Molar mass of Magnesium carbonate is : 84

Moles of Magnesium carbonate in 250 ml is :

21 / 84 = 0.25 moles

Moles in 25 ml is :

(25 / 250) × 0.25 = 0.025 moles

These moles will be in 1250 ml

The molarity of the resulting solution is thus :

(1000 / 1250) × 0.025 = 0.02 M

Answer 2

Explanation:

Ag3A = 3Ag + A

3 moles of Ag combine with 3 moles of A

Mass of Ag = 0.37

Mass of A = 607 - 0.37 = 606.63

Moles of Ag = 0.37/108 = 0.003426

Moles of A = 0.003426/3 = 0.001142

Molar mass of A = 606.63/0.001142 = 531211

A tribasic acid has 3 atom of H

Molar mass of the acid = 3 + 531211 = 531214 g/mol