Electrolytic processes & chemical changes (3.2-4.2)

Question 1

What is electrolysis?

Answer 1

The breaking down of compounds done by passing an electric current through a liquid or solution containing ions

Question 2

What is PANIC?

Answer 2

P - Positive
A - Anode/Anion
N - Negative
I - Is
C - Cathode/Canion

Question 3

Electrolysis uses energy transferred by electricity to decompose _____

Answer 3

Electrolytes

Question 4

What are electrodes?

Answer 4

An electrical conductor used to make contact with a nonmetallic part of a circuit

Question 5

What are the 2 electrodes connected to?

Answer 5

D.C. - direct current

Question 6

What is OILRIG

Answer 6

O - Oxidation
I - Is
L - Loss (of electrons)

R - Reduction
I - Is
G - Gain (of electrons)

Question 7

What does the transfer of electrons do to charged ions?

Answer 7

Changes them into atoms or molecules

Question 8

How is the transfer of electrons and the changing of charged ions into atoms or molecules represented

Answer 8

Half equations

Question 9

What is the half equation for the electrolysis of molten Zn²⁺ (hint: its reduction)

Answer 9

Zn²⁺ + 2e -> Zn (reduction)

Question 10

What is the half equation for the electrolysis of Cl⁻ (hint: its at the anode)

Answer 10

2Cl⁻ -> Cl₂ + 2e

(note how 2 cl- ions are needed to form one chlorine molecule)

Question 11

Pb²⁺ + 2e -> Pb

Is this oxidation or reduction

Answer 11

Reduction because the lead loses 2 electrons

Question 12

What is dynamic equilibrium?

Answer 12

An equilibrium in which the rate of reaction is equal on one side of the ⇄ symbol

Question 13

What conditions are optimal for the Haber process?

Answer 13

1. 450⁰C
2. 200 atm
3. Iron as a catalyst

Question 14

What group are alkali metals and why are they called alkali metals?

Answer 14

1. Group 1
2. They turn water alkaline when they are placed in water

Question 15

Why is calcium lower on the reactivity series than potassium despite them being on the same period?

Answer 15

Potassium has more electron shells, therefore the electromagnetic attraction between the nucleus & electron shells are lower the further you go out, making the shells unstable

Question 16

What is redox

Answer 16

Reduction & Oxidation happening at the same time (for example:Zn+CuSO4->ZnSO4+Cu)

Question 17

What is a displacement reaction

Answer 17

A reaction in which the atom bonded with another atom is displaced by anther atom becausse the 2nd atom is more reactive

Question 18

What is a metal ore

Answer 18

A rock containing enough ore to make it worthwile extracting

Question 19

Why do you need electrolysis to extract metals higher in the RS than Carbon?

Answer 19

They are to reactive to be displaced by Carbon in carbon reduction, so electrolysis must be used

Question 20

What is a disadvantage of using electrolysis to extract ores

Answer 20

Extremely expensive

Question 21

What 2 elements aren’t needed to be extracted and why?

Answer 21

Silver and gold are found as pure elements

Question 22

How are elements lower than carbon (besides Ag+Au) on the reactivity series extracted

Answer 22

They are reacted with a reducing agent, most commonly Carbon, as it is cheap. It works by a simple displacement reaction

Question 23

What is an advantage of using a reducing agent like carbon to extract ores?

Answer 23

Its cheap

Question 23

What is bioleaching

Answer 23

When certain bacteria are grown on low grade ores that can break down these ores to make a substance called lechate, containing metal irons

Question 24

Give 2 advantages of bioleaching

Answer 24

1. Very cheap as no energy is required 2. No harmful gasses are produced

Question 25

Give 2 disadvantages of bioleaching

Answer 25

1. Toxic chemicals are produced 2. Extremely slow

Question 26

What is phytoextraction

Answer 26

When plants are grown on low grade ore, the plants absorb metal ions through these roots and concentrate these ions in their cells. Then, the plants are burned and the ash left behind has a higher conc of metal than before, which is processed to obtain metal

Question 28

Give 2 advantages of phytoextraction

Answer 28

1. No harmful gasses produced 2. Dosen't damage landscape

Question 29

Give 2 disadvantages of phytoextraction

Answer 29

1. Very slow 2. Can more expensive than mining ores

Question 30

What is a reversible reaction

Answer 30

A reaction that can be put in opposite order and still react

Question 31

Give an example of a reversible reaction

Answer 31

The haber process

Question 32

What is the haber process & why is it useful?

Answer 32

The haber process is used to "make" ammonia, and formula is N₂+3H₂ ⇌ 2NH₃

Question 33

How does the position of equilibrium shift in an exothermic reaction when the temperature increases?

Answer 33

The position of equilibrium will change from going backwards to forwards which cools down up as it is an endothermic reaction

Question 34

Key fact

Answer 34

Think of dynamic equilibrium as "no you don't"

Question 35

Define the key word ‘dynamic equilibrium’

Answer 35

A state where the rate of the forward reaction equals the rate of the reverse reaction ## Footnote Dynamic equilibrium occurs in reversible reactions.

Question 36

Why is using a very low temperature preferable by industry in the Haber Process?

Answer 36

It shifts the equilibrium towards the production of ammonia ## Footnote The Haber Process is exothermic, and lower temperatures favor the formation of products.

Question 37

What are transition metals?

Answer 37

Elements that have partially filled d-orbitals ## Footnote Transition metals exhibit unique properties and behaviors due to their d-electrons.

Question 38

List common properties of transition metals.

Answer 38

* Malleable * Ductile * Conductors * Shiny when polished * High melting and boiling points * High densities ## Footnote Most transition metals exhibit these properties.

Question 39

What is an example of a use for iron?

Answer 39

Used to make bridges, buildings, ships, and cars ## Footnote Iron's malleability and strength make it suitable for construction.

Question 40

Why is copper used for electrical wires?

Answer 40

It is ductile and a good electrical conductor ## Footnote Copper's properties allow it to be easily shaped and conduct electricity efficiently.

Question 41

What is unique about mercury among transition metals?

Answer 41

It is a liquid at room temperature ## Footnote Mercury melts at -39 °C and boils at 356 °C.

Question 42

What general relationship exists between density and atomic radius in transition metals?

Answer 42

As atomic radius increases, density generally increases ## Footnote This relationship can be observed in the periodic trends of transition metals.

Question 43

What do cobalt, nickel, and copper have in common in terms of their properties?

Answer 43

They are all transition metals with high melting points ## Footnote Their positions in period 4 show consistent trends.

Question 44

Describe the typical chemical properties of transition metals.

Answer 44

* Formation of coloured compounds * Catalysts that speed up reactions without being consumed ## Footnote Transition metals typically form colorful compounds, unlike Group 1 and 2 metals.

Question 45

What is a chemical property?

Answer 45

A characteristic of a substance observed during a chemical reaction ## Footnote Chemical properties include reactivity, acidity, and oxidation states.

Question 46

What are alloy steels made from?

Answer 46

Iron alloyed with other transition metals such as cobalt and chromium ## Footnote Alloy steels enhance strength and resistance to corrosion.

Question 47

Fill in the blank: Transition metals typically form _______ compounds.

Answer 47

[coloured]

Question 48

True or False: Aluminium and Group 1 and 2 metals usually form coloured compounds.

Answer 48

False ## Footnote Aluminium and Group 1 and 2 metals typically form white or colourless compounds.

Question 49

What is the role of iron in the Haber Process?

Answer 49

It acts as a catalyst ## Footnote Iron increases the rate of ammonia production without being consumed in the reaction.