Chemical Engineering Chapter 13 Homework Gives Answer The Unit Moles Solute

Solutions 13

Chapter Overview

Chapter 13 discusses what a solution is and how we characterize its properties and

concentrations. Background is given and appropriate calculations are shown. Practical

applications of solutions phase reactions are given and explained.

Lecture Outline

13.1 Tragedy in Cameroon

13.2 Solutions: Homogeneous Mixtures

Learning Objective: Define solution, solute, and solvent.

13.3 Solutions of Solids Dissolved in Water: How to Make Rock Candy

Learning Objective: Relate the solubility of solids in water to temperature.

A. Solubility and saturation

1. Saturated: solvent holding as much solute as it can

3. Supersaturated: solvent holding more than the maximum amount of solute

B. Electrolyte solutions: dissolved ionic solids

2. Nonelectrolyte solution

C. Solubility is temperature dependent

D. Rock candy

13.4 Solutions of Gases in Water: How Soda Pop Gets Its Fizz

13.5 Specifying Solution Concentration: Mass Percent

Learning Objective: Calculate mass percent.

Learning Objective: Use mass percent in calculations.

13.6 Specifying Solution Concentration: Molarity

Learning Objective: Calculate molarity.

A. Molarity (M) =

moles solute

13.7 Solution Dilution

13.8 Solution Stoichiometry

Learning Objective: Use volume and concentration to calculate the number of moles of

13.9 Freezing-Point Depression and Boiling-Point Elevation: Making Water Freeze Colder and

Boil Hotter

Learning Objective: Calculate molality.

13.10 Osmosis: Why Drinking Salt Water Causes Dehydration

Learning Objective: Summarize and explain the process of osmosis.

Chemical Principle Teaching Ideas

Solutions

Students usually associate solutions as liquid (usually water) with solid dissolved in it,

but in fact any two species mixed can make a solution. Give an example and show each different

combination to the students.

Solid and Water Solutions

Gas and Water Solutions

Solution Concentration

There are many different ways to express the concentration of a solution, and each of

Solution Dilution

Because adding water to a solution does not change the moles of solute, we can use the

fact that M1V1 gives an answer in the unit of moles of solute and is equal to M2V2.

Freezing-Point Depression and Boiling-Point Elevation

Why do we put antifreeze in our cars? Why do we put salt on icy roads? Why does soup

boil hotter than pure water? All of these are practical, real-world examples of these concepts and

are easy for the students to understand.

Osmosis

Skill Builder Solutions

1.00 g H O

13.2.

355 mL solution 1.04 g solution

1 mL solution

12 22 11

11.5 g C H O

100 g solution

12 22 11

= 42.5 g C H O

0.135 mol HNO

23

1 mol Na CO

Plus.

0.108 mol Na CO

3

2 mol HNO

1

13.10. Tb = m x Kb =

3.5 mol glucose

0.512 C kg solvent

1 mol glucose = 1.8 C

Suggested Demonstrations

Bring examples of each combination of solids, liquids, and gases in solutions. Explain each

example, how the solutions are of various concentrations, and how each behaves.

Ice cream is made by freezing cream using a salt-ice bath. Explain how it is made, and make

1:27, Shakhashiri, B.Z. University of Wisconsin Press, 1983.

Density and Miscibility of Liquids, Chemical Demonstrations 3:233, Shakhashiri, B.Z.

Guided Inquiry Ideas

Below are a few example questions that students answer in the guided inquiry activities provided

in the Guided Activity Workbook.

Are solids (e.g., salt) more soluble in hot water or cold water?

Trout only live in very cold mountain lakes and streams. How much oxygen is in that water

compared to the tropics?