Lesson 34: Half-equations

• Chemistry
• Secondary Education

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CHEMISTRY 10

34 - Constructing half-equations

Week 23

• construct ionic half-equations for reactions at the anode (to show oxidation) and at the cathode (to show reduction).

_______________  is the breakdown of an ionic compound, molten or in aqueous solution, by the use of electricity.

1. Electrochemical
2. Electrolytic cell
3. Electrolysis
4. Electrodes

Which of the following is a property related to the electrolysis of an ionic compound like sodium chloride?

1. thermal conductivity
2. luster
3. electrical conductivity
4. tensile strength

Potassium nitrate contains NO3- ions.

 The oxidation number of O atoms in NO3- is –2.

 Determine the oxidation number of N atoms in NO3– ions. 

1. +3
2. +4
3. +2
4. +5

Which of the labelled parts is the positive electrode?

1. a
2. c
3. d
4. b

Concentrated magnesium bromide is electrolysed using graphite electrodes.

What product is formed at the cathode (-)?

1. oxygen gas
2. molecular bromine
3. magnesium metal
4. hydrogen gas

Concentrated magnesium bromide is electrolysed using graphite electrodes.

What product is formed at the cathode (-)?

1. oxygen gas
2. molecular bromine
3. magnesium metal
4. hydrogen gas

Concentrated copper(II) sulfate is electrolysed using graphite electrodes.

What product is formed at the cathode (-)?

1. oxygen gas
2. sulfate ions
3. copper metal
4. hydrogen gas

Concentrated magnesium bromide is electrolysed using graphite electrodes.

What product is formed at the anode (+)?

1. oxygen gas
2. molecular bromine
3. magnesium metal
4. hydrogen gas

Molten sodium chloride is electrolysed using graphite electrodes.

What product is formed at the anode (+)?

1. oxygen gas
2. molecular chlorine
3. sodium metal
4. hydrogen gas

Molten sodium chloride is electrolysed using graphite electrodes.

What product is formed at the cathode (-)?

1. oxygen gas
2. molecular chlorine
3. sodium metal
4. hydrogen gas

Dilute aqueous potassium iodide is electrolysed using graphite electrodes.

What product is formed at the anode (+)?

1. oxygen gas
2. molecular iodine
3. potassium metal
4. hydrogen gas

Dilute aqueous potassium iodide is electrolysed using graphite electrodes.

What product is formed at the cathode (-)?

1. oxygen gas
2. molecular iodine
3. potassium metal
4. hydrogen gas

Which of the following is NOT why graphite is a suitable electrode?

1. It's a good conductor of electricity
2. It's chemically stable/inert.
3. It can withstand high temperatures.
4. It's quickly replaceable.

What type of particles are responsible for the charge transfer in the conducting wires?

1. protons
2. electrons
3. neutrons
4. ions

What type of particles are responsible for the charge transfer in an electrolyte, such as aqueous sodium chloride?

1. protons
2. electrons
3. neutrons
4. ions

The equation for the reaction of iron with carbon monoxide is:

 Fe2O3 +  3CO → 2Fe +  3CO2
Describe how this equation shows that iron is reduced.

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CHEMISTRY 10

QUIZ 2.1

Week 23

Test / Quiz 2.1

• Read and follow all instructions carefully.
• Keep the focus on your own paper.
• Use your pen for answers and pencil for diagrams, if there are any.
• If you have any questions, please raise your hand.