   Chapter 14, Problem 186CP

Chapter
Section
Textbook Problem

# A sample containing 0.0500 mole of Fe2(SO4)3 is dissolved in enough water to make 1.00 L of solution. This solution contains hydrated SO42− and Fe3+ ions. The latter behaves as an acid: Fe ( H 2 O ) 6 3 + ( a q ) ⇌ Fe ( H 2 O ) 5 OH 2 + ( a q ) + H + ( a q ) a. Calculate the expected osmotic pressure of this solution at 25°C if the above dissociation is negligible.b. The actual osmotic pressure of the solution is 6.73 atm at 25°C. Calculate Ka for the dissociation reaction of Fe(H2O)63+. (To do this calculation, you must assume that none of the ions go through the semipermeable membrane. Actually, this is not a great assumption for the tiny H+ ion.)

(a)

Interpretation Introduction

Interpretation: The expected osmotic pressure of the given solution of Fe2(SO)4 and the value of Ka for the dissociation reaction of Fe(H2O)63+ is to be calculated.

Concept introduction: Osmotic pressure is the amount of pressure required to be applied across a semi-permeable membrane in order to stop the flow of solvent molecules in a solution of lower concentration to higher concentration. Osmotic pressure is a colligative property. The value of osmotic pressure is calculated by the formula.

π=i×C×R×T

To determine: The expected osmotic pressure of the given solution of Fe2(SO)4

Explanation

Explanation

The value of concentration is calculated by the formula,

Concentration(C)=NumberofmolesVolume(L)

Substitute the values of number of moles and volume for the Fe2(SO)3 solution in the above expression.

Concentration(C)=0.0500mol1LC=0.0500mol/L

The dissociation reaction of Fe2(SO)3 is,

Fe2(SO4)32Fe+3+3SO42

The above reaction clearly indicates the dissociation of 5 ion molecules. Thus, the value of i is 5.

The value of osmotic pressure is calculated by the formula,

π=i×C×R×T

Where,

• i is the Van’t Hoff factor

(b)

Interpretation Introduction

Interpretation: The expected osmotic pressure of the given solution of Fe2(SO)4 and the value of Ka for the dissociation reaction of Fe(H2O)63+ is to be calculated.

Concept introduction: Osmotic pressure is the amount of pressure required to be applied across a semi-permeable membrane in order to stop the flow of solvent molecules in a solution of lower concentration to higher concentration. Osmotic pressure is a colligative property. The value of osmotic pressure is calculated by the formula.

π=i×C×R×T

To determine: The value of Ka for the dissociation reaction of Fe(H2O)63+.

### Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

#### The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started

#### How do eating disorders affect health?

Understanding Nutrition (MindTap Course List)

#### How can errors in the cell cycle lead to cancer in humans?

Human Heredity: Principles and Issues (MindTap Course List)

#### What are some features common to erosional coasts?

Oceanography: An Invitation To Marine Science, Loose-leaf Versin 