6.6 The Electrical Properties of Condensed Phases Questions

Questions :

Which of the following liquids completes an electric circuit?

a) Distilled water

b) An aqueous solution of sodium chloride

c) An aqueous solution of sugar

2. What is an electric current?

3. When NaCl dissolves in water, we have (identify the correct choices)

a) sodium ions, represented by Na+(aq)

b) chloride ions, represented by Cl–(aq)

c) solid sodium chloride forming ions as follows: NaCl(s) →Na+(aq)+Cl-(aq)

4. Define “ion”. 

5. Which of the following points is necessary for an electric current to flow through an aqueous solution?

a) An electric current flows when we have a complete circuit.

b) Current flows outside the battery from the positive terminal to the negative terminal.

c) Inside the battery, the current moves from the positive side to the negative side.

d) In an ionic solution connected to a battery, all positive ions move in the direction of the

current, away from the positive electrode and towards the negative electrode. All negative

ions move in a direction opposite to the current, away from the negative electrode and

towards the positive electrode.

e) All the above are correct

6. Why CaCl2 solution conducts current but sugar in water does not

Why does aqueous CaCl2 solution conduct electricity but sugar in water does not?

Which of the following is a part of the explanation?

a) Sugar solution in water forms only one type of ion: Sugar(aq).

b) Calcium chloride forms two types of ions: CaCl2(s) → Ca2+(aq) + 2Cl–(aq).

c) Calcium chloride provides Ca+(aq) and Cl–(aq).

7. One mole of silver nitrate, AgNO3, in water provides how many moles of ions?

a) One mole of Ag+(aq) and one mole of N–.

b) One mole of Ag+(aq) and three moles of NO3− (aq).

c) One mole of Ag+(aq) and four moles of negative ions (aq).

d) One mole of Ag+(aq) and one mole of negative nitrate ions, NO3− (aq).

e) Five moles of ions

8. Which solid is not soluble in water?

a) Silver chloride, AgCl.

b) Silver nitrate, AgNO3.

c) Sodium chloride, NaCl.

d) Calcium chloride, CaCl2.

e) Ammonium chloride, NH4Cl.

9.Precipitation in chemistry means:

a) Rain falling on a plain.

b) The reaction where a gas is formed.

c) The condensation that results when the vapors of a liquid are cooled.

d) The formation of steam.

e) The formation of solid from a solution.

10. In the reaction Ag+(aq) + NO3− (aq) + Na+(aq) + Cl−(aq) → AgCl(s) + NO3− (aq) + Na+(aq)

The predominant reacting species is/are

a) NO3− (aq).

b) Na+(aq).

c) Na+(aq) and NO3− (aq).

d) Cl−(aq) and Ag+(aq).

e) Ag+(aq) and Na+(aq).

11. Which sets of numbers balance the three equations below (respectively)? [Check for charge and atoms]

1) MgCl2(s) → Mg2+(aq) + Cl−(aq).

2) Na2Cr2O7(s) → Na+(aq) + Cr2O72−(aq).

3) Cr2O72−(aq) + H2O → CrO42−(aq) + H+(aq).

a) 1, 2, 1; 1, 2, 2; 2, 1, 2, 2

b) 1, 1, 2; 1, 2, 1; 1, 1, 2, 2

c) 2, 1, 2; 1, 2, 1; 1, 2, 2, 2

d) 1, 1, 3; 3, 2, 1; 1, 1, 2, 2

e) 1, 2, 2; 2, 2, 1; 1, 1, 1, 1

Answers :

Which of the following liquids completes an electric circuit?

a) Distilled water

b) An aqueous solution of sodium chloride

c) An aqueous solution of sugar

2. What is an electric current?

Electric current is the movement of electric charge.

3. When NaCl dissolves in water, we have (identify the correct choices)

a) sodium ions, represented by Na+(aq)

b) chloride ions, represented by Cl–(aq)

c) solid sodium chloride forming ions as follows: NaCl(s) →Na+(aq)+Cl-(aq)

4. Ions are atoms or molecules that carry electric charge.

5. Which of the following points is necessary for an electric current to flow through an aqueous solution?

a) An electric current flows when we have a complete circuit.

b) Current flows outside the battery from the positive terminal to the negative terminal.

c) Inside the battery, the current moves from the positive side to the negative side.

d) In an ionic solution connected to a battery, all positive ions move in the direction of the

current, away from the positive electrode and towards the negative electrode. All negative

ions move in a direction opposite to the current, away from the negative electrode and

towards the positive electrode.

e) All the above are correct

6. Why CaCl2 solution conducts current but sugar in water does not

Why does aqueous CaCl2 solution conduct electricity but sugar in water does not?

Which of the following is a part of the explanation?

a) Sugar solution in water forms only one type of ion: Sugar(aq).

b) Calcium chloride forms two types of ions: CaCl2(s) → Ca2+(aq) + 2Cl–(aq).

c) Calcium chloride provides Ca+(aq) and Cl–(aq).

7. One mole of silver nitrate, AgNO3, in water provides how many moles of ions?

a) One mole of Ag+(aq) and one mole of N–.

b) One mole of Ag+(aq) and three moles of NO3− (aq).

c) One mole of Ag+(aq) and four moles of negative ions (aq).

d) One mole of Ag+(aq) and one mole of negative nitrate ions, NO3− (aq).

e) Five moles of ions

8. Which solid is not soluble in water?

a) Silver chloride, AgCl.

b) Silver nitrate, AgNO3.

c) Sodium chloride, NaCl.

d) Calcium chloride, CaCl2.

e) Ammonium chloride, NH4Cl.

9.Precipitation in chemistry means:

a) Rain falling on a plain.

b) The reaction where a gas is formed.

c) The condensation that results when the vapors of a liquid are cooled.

d) The formation of steam.

e) The formation of solid from a solution.

10. In the reaction Ag+(aq) + NO3− (aq) + Na+(aq) + Cl−(aq) → AgCl(s) + NO3− (aq) + Na+(aq)

The predominant reacting species is/are

a) NO3− (aq).

b) Na+(aq).

c) Na+(aq) and NO3− (aq).

d) Cl−(aq) and Ag+(aq).

e) Ag+(aq) and Na+(aq).

11. Which sets of numbers balance the three equations below (respectively)? [Check for charge and atoms]

1) MgCl2(s) → Mg2+(aq) + Cl−(aq).

2) Na2Cr2O7(s) → Na+(aq) + Cr2O72−(aq).

3) Cr2O72−(aq) + H2O → CrO42−(aq) + H+(aq).

a) 1, 2, 1; 1, 2, 2; 2, 1, 2, 2

b) 1, 1, 2; 1, 2, 1; 1, 1, 2, 2

c) 2, 1, 2; 1, 2, 1; 1, 2, 2, 2

d) 1, 1, 3; 3, 2, 1; 1, 1, 2, 2

e) 1, 2, 2; 2, 2, 1; 1, 1, 1, 1