Module 4 Intro

1. Module 4 Intro

1.8. Page 6

Lesson 1

Module 4—Properties of Solutions

Going Beyond

Microbiological and Chemical Contamination of Drinking Water

A great deal of concern exists about substances in drinking water. Water purification processes focus on removing many micro-organisms that have the potential to be harmful. Recently additional attention has been placed on the presence of metals, pesticides, and pharmaceutical products that may be present in the water supply.

Further information about these sources of contamination can be accessed here.

Self-Check

SC 4. A number of solutions are listed in the following table. Fill in the table, using the example to guide you.

Mixture	Type of Solution	Solute	Solvent
carbonated water	gas in liquid	carbon dioxide	water
mercury amalgam dental filling
brass
grape juice from a powder
alcoholic beverage
milk
humid air
18-k gold ring
smoke-filled air
oxygen dissolved in water

SC 5. Classify each of the following substances as an electrolyte or a nonelectrolyte. Also, indicate whether the solution will be acidic, basic, neutral ionic, or neutral molecular.

liquid bromine, Br2(l)
table salt, NaCl(aq)
table sugar, C12H22O11(s)
methanol, CH3OH(l)
lye, NaOH(aq)

SC 6. There are four beakers containing visually identical solutions. If the potential solutions are HCl(aq), NaOH(aq), NaCl(aq), and C12H22O11(aq), design an experiment that will determine the solution in each beaker.

Check your work.

Self-Check Answers

SC 4.

Mixture	Type of Solution	Solute	Solvent
carbonated water	gas in liquid	carbon dioxide	water
mercury amalgam dental filling	liquid in solid	mercury	silver
brass	solid in solid	tin	copper
grape juice from a powder	solid in liquid	powder	water
alcoholic beverage	liquid in liquid	ethanol	water
milk	not a solution
humid air	gas in gas	water vapour	air (or nitrogen)
18-k gold ring	solid in solid	various metals	gold
smoke-filled air	not a solution
oxygen dissolved in water	gas in liquid	oxygen	water

SC 5.

nonelectrolyte, neutral molecular
electrolyte, neutral ionic
nonelectrolyte, neutral molecular
nonelectrolyte, neutral molecular
electrolyte, basic

Note the difference between CH3OH and NaOH. CH3OH is molecular and does not dissolve in water; NaOH is ionic and will dissolve in water.

SC 6. First, do a conductivity test. The solution that does not conduct electricity is C12H22O11(aq). Since the remaining three beakers all conduct electricity, they can be distinguished using a litmus test. The solution that turns blue litmus red is HCl(aq), the solution that has no effect on either colour is NaCl(aq), and the solution that turns red litmus blue is NaOH(aq).