Electrical Conductivity + Electrolysis (1)

Question 1

Electrical conductivity is all about the movement of electrons or _______

Answer 1

Ions

Question 2

Electrons have a negative charge. What about ions?

Answer 2

They can have either positive or negative

Question 3

_____________ or ______ can act as charge carriers - they can move charge around a system to create a flow of ________________

Answer 3

Electrons
Ions
Electricity

Question 4

The electric current is the flow of ___________ or _______

Answer 4

Electrons or ions

Question 5

Ionic compounds are made of a lattice of positive and negative ______

Answer 5

Ions

Question 6

Why don’t solid ionic compounds conduct electricity

Answer 6

Because the ions aren’t free to move around

Question 7

Can ionic compounds conduct electricity…

Answer 7

When molten or in solution

Question 8

Why can an ionic compound conduct electricity when dissolved or molten

Answer 8

The ions separate and are free to move around in the solution. This means that they’ll carry electric current and so conduct electricity.

Question 9

Can covalent compounds conduct electricity

Answer 9

No (except graphite)

Question 10

Why can’t covalent compounds conduct elctricity

Answer 10

They don’t contain ions because they make bonds by sharing electrons. This means that they don’t have any charge carriers that are free to move - so they can’t carry an electric current

Question 11

Metals are held together by ____________ bonding

Answer 11

Metallic

Question 12

Metals have giant structures of ______________ ions surrounded by a sea of delocalised (free) ____________

Answer 12

Positive ions surrounded by a sea of delocalised (free) electrons

Question 13

The attraction between positive ions and the delocalised electrons is called _____________ bonding. It’s this ______________ bonding which gives metals their ______________

Answer 13

Metallic
Metallic
Properties

Question 14

Metals are good conductors of electricity and heat. Why?

Answer 14

Because the delocalised electrons carry electrical current and heat energy through the material.

Question 15

The layers of atoms in a metal can slide over each other, making materials _______________ - this means that they can be hammered or rolled into flat sheets

Answer 15

Malleable

Question 16

What is electrolysis

Answer 16

The decomposition of an ionic substance using electricity

Question 17

What is an anode

Answer 17

The positive electrode

Question 18

What is a cathode

Answer 18

The negative electrode

Question 19

Cations are ________________ ions which are attracted to the _________________ electrode (also known as the ____________). They __________ electrons and are _____________

Answer 19

Positive
Negative
Cathode
Gain
Reduced

Question 20

Anions are ________________ ions which are attracted to the _________________ electrode (also known as the ____________). They __________ electrons and are _____________

Answer 20

Negative
Positive
Anode
Lost
Oxidised

Question 21

If you pass an electric current through an __________ substance that’s molten or in solution it breaks down into new ______________. This is called ________________

Answer 21

Ionic
Substances
Electrolysis

Question 22

Electrolysis requires a liquid to conduct the electricity, called the _____________

Answer 22

Electrolyte

Question 23

How are electrolytes made?

Answer 23

By melting or dissolving ionic compounds

Question 24

How does an electrolyte conduct electricity

Answer 24

Via the free ions

Question 25

For the circuit to be complete, there's got to be a flow of _____________. Electrons are taken away from ions at the ____________ and given to the other ions at the _____________

Answer 25

Electrons Anode Cathode

Question 26

As ions gain or lose electrons they become _________ or ____________

Answer 26

Atoms | Molecules

Question 27

What are electrolytes

Answer 27

Liquids that conduct electricity

Question 28

Why can't a covalent compound conduct electricity

Answer 28

Because they have no free electrons and no ions

Question 29

One way to distinguish between electrolytes and non-electrolytes. When you place a conductivity probe in an ______________, current flows through the circuit - so you can measure its ______________. What happens if you place it in a non-electrolyte?

Answer 29

Electrolyte Conductivity You get a reading of 0 conductivity - no flow

Question 30

Molten ionic _____________ can be _____________ easily because the ions can move freely. They're usually broken up into their ____________.

Answer 30

Compounds Electrolysed Elements

Question 31

Common example of electrolysis:

Answer 31

Molten lead bromide

Question 32

Pb2+ + 2e- -->

Answer 32

Pb

Question 33

2Br- --->

Answer 33

Br2 + 2e-

Question 34

What is the difference with electrolysis of aqueous solutions

Answer 34

There will be hydrogen ions and hydroxide ions from the water

Question 35

Aqueous electrolysis: | At the cathode, what happens if H+ ions and metal ions which are more reactive than them are present

Answer 35

Hydrogen gas will be produced if the metal ions are more reactive than the H+ ions.

Question 36

Aqueous electrolysis: | At the cathode, what happens if H+ ions and metal ions which are less reactive than them are present

Answer 36

A solid layer of the pure metal will be produced

Question 37

What happens at the anode, if OH- and halide ions are present

Answer 37

Molecules of chlorine, bromine or iodine will be formed

Question 38

What happens at the anode, if OH- and no halide ions are present

Answer 38

Oxygen will be formed

Question 39

How can you increase the number electrons transferred

Answer 39

Time - (electrolysing for a longer time) | Current - increasing

Question 40

What does the amount of product made by electrolysis depend on

Answer 40

The number of electrons that are transferred

Question 41

At the negative electrode: Metal ions and hydrogen ions are positively charged. Whether you get the metal or hydrogen during electrolysis depends on the position of the metal in the reactivity series. If the metal is more reactive than hydrogen which will be produced?

Answer 41

Hydrogen

Question 42

Which will be produced if the metal is less reactive than hydrogen?

Answer 42

The metal

Question 43

What is brine

Answer 43

Concentrated sodium chloride solution

Question 44

What happens if brine is electrolysed

Answer 44

Hydrogen gas forms at the negative electrode Chlorine gas forms at the positive electrode Also a solution of sodium hydroxide forms