1. A student determines the iron(II) content of a solution by first precipitatin

Question

1. A student determines the iron(II) content of a solution by first precipitating it as iron(II) hydroxide, and then decomposing the hydroxide to iron(II) oxide by heating. How many grams of iron(II) oxide should the student obtain if her solution contains 54.0 mL of 0.530 M iron(II) nitrate?

________ g

2.   A 0.4999 g sample of a pure soluble chloride compound is dissolved in water, and all of the chloride ion is precipitated as AgCl by the addition of an excess of silver nitrate. The mass of the resulting AgCl is found to be 1.6118 g.

What is the mass percentage of chlorine in the original compound? ________ %

Explanation / Answer

1) 0.530M Fe(NO3)2= 0.530 mole in 1000ml

No of mole of Fe(NO3)2 in 54ml = (0.530mol/1000ml)×54ml= 0.02862 mole

Therefore , No of mole of Fe = 0.02862

Molar mass of Fe = 55.845g

Therefore, Mass of Fe present in 54ml solution = 0.02862×55.845 = 1.598g

Molar mass of FeO = 71.845g

55.845g of Fe give 71.845g of FeO

Therefore,

1.598g of Fe give ( 71.845/55.845)×1.598g = 2.0558g of FeO

The student obtain 2.0558g of FeO

2.) Molar mass of AgCl = 143.32g

Molar mass of Cl = 35.45g

143.32g of AgCl contain 35.45g of AgCl

Mass of AgCl obtained = 1.6118g

Therefore , mass of Cl = (35.45g/143.32g)× 1.6118g = 0.39867g

0.39867g of Chlorine present in the solution

So, mass percentage of the Chlorine in sample = (0.39867/0.4999) × 100 = 79.75%

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.