Consider a 1.24 g mixture of magnesium nitrate and magnesium chloride. after dissolving this mixture in water, 0.500 m silver nitrate is added dropwise until precipitate formation is complete. the mass of the white precipitate formed is 0.419 g. calculate the mass percent of magnesium chloride in the mixture. % mgcl2 determine the minimum volume of silver nitrate that must have been added to ensure complete formation of the precipitate. ml agno3

Explanation:

Step 1: Balance the reaction

MgCl2 (aq) + 2 AgNO3 (aq)  → 2AgCl (s) + Mg(NO3)2 (aq)

For 1 mole MgCl2 we have 1 mole Mg(NO3)2, but 2 moles AgNO3 and 2 moles AgCl

Step 2 : Calculating moles

⇒Mass of magnesium nitrate (Mg(NO3)2 )  and magnesium chloride (MgCl2) = 1.24g

⇒Molarity of the silver nitrate (AgNO3) = 0.5M

⇒The mass of the white precipitate formed is 0.419 g

mole AgCl = mass AgCl / Molar mass AgCl

mole AgCl = 0.419g / 143.32g/mole = 0.002935 mole

Step3 : Calculating mass

For 2 mole AgCl we have 1 mole MgCl2, so to find the mole of MgCl2 we have to divide by 2

mole MgCl2 = 0.002935 mole/2 = 0.0014618 mole

mass MgCl2 = 0.0014618 mole * 95.211g/mole =0.13918 g

Mixture has a mass of 1.24g

Mgcl2 has a mass of 0.13918g

(0.13918 / 1.24) x 100% = 11.224 %

⇒11.224% of the mixture is MgCL2

b) 0.002935 mole of AgCl gives 0.002935 mole of AgNO3

Molarity = moles / volume  or moles = molarity * volume

⇒ 0.002935 moles = 0.500 M * volume

volume = 0.002935 moles / 0.5 M = 0.00587 L = 5.87 mL

The minimum volume of silver nitrate that must have been added = 5.87 mL

explanation:

two years ago, when picking flowers in the mountains back of yosemite valley, i found a book. it was blotted and storm-beaten; all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however; many of the inner pages were well preserved. and although all were more or less stained and torn, whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today; its granite pages have been torn and blurred by the same storms that wasted the castaway book.

two years ago, when picking flowers in the mountains back of yosemite valley; i found a book. it was blotted and storm-beaten, all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however, many of the inner pages were well preserved. and although all were more or less stained and torn; whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today, its granite pages have been torn and blurred by the same storms that wasted the castaway book.