Electrical Conductivity

Questions (copy them out first)

Give the definition and an example for the following terms:

1)A solution is__________________?2)An aqueous solution is___________?3)Concentration in PPM____________?4) What is the percent of KCl if 15 g

KCl are placed in 75 g water?5) p.28 of your workbook question 1

& 2

Electrolyte and Non-electrolyte

• Electrolyte: a substance that conducts electricity when dissolved in water.

Electrolytes

• Some solutes can dissociate into ions.

Types of solutes

Na+

Cl-

Strong Electrolyte -100% dissociation,all ions in solution

high conductivity

• Electrical Conductivity: Is a measure of a solutions ability to allow an electric current to flow through it.

• Electrolytic Dissociation:Is the separation of a dissolved

compound into two ions of opposite charges

Question?

1) What happens when an electrolyte is dissolved in water? (give an example)

2) What happens when a nonelectrolyte is dissolved? (give an example)

• What happens when an electrolyte is dissolved in water?

Answer: Ions are produced. Example NaCl (table salt)

The ions formed during electrolytic dissociation conduct electricity.

•What happens when a nonelectrolyte is dissolved?

Answer: No ions are producedExample: Sugar

Types of Electrolytes

1) Acids Is a substance that releases H+ ions in an aqueous solution

2) Bases Is a substance that releases OH- ions in an aqueous solution

3) Salts Is a substance produced by the chemical bonding of a metallic ion and a nonmetallic ion (not H+ and OH-)

Questions

• Give two examples of an acid, a base, and a salt and show how they dissociate in an aqueous solution.

Answer

Acid:Hydrochloric AcidHCl(g) H+

(aq) + Cl-(aq)

Look at page 58 & 59 for tips

• The pH scale measures how acidic or basic a substance is. • The pH scale ranges from 0 to 14. • A pH of 7 is neutral. • A pH less than 7 is acidic. • A pH greater than 7 is basic.

Questions

• A solution with a pH of 4 is 10times more acidic than a solution with a pH of 5

1) How many times more acidic is a solution of pH 2 than a solution with pH 4?

2) How many times less basic is a solution with a pH 8 compared to a solution with pH 11?

• 1) How many times more acidic is a solution of pH 2 than a solution with pH 4?

Answer: 100

• 2) How many times less basic is a solution with a pH 8 compared to a solution with pH 11?

Answer: 1000

In Class Work

Page 64 & 65 of your textbook. Do questions:

31, 32, 33 and A on page 65