7. Equilibrium

Question 1

Equilibrium

Answer 1

Needs to be a closed system. When the rate of forward reaction is equal to the rate of the backward reaction in a reversible reaction, equilibrium is achieved.

Question 2

2 types of equilibrium

Answer 2

Physical and Chemical

Physical is only when the state changes

Chemical is when a new substance is formed

Question 3

Chemical Equilibrium

Answer 3

Chemical occurs when the concentrations of reactants and products in a chemical reaction remain constant over time

Question 4

Le-Chatlier’s Principle

Answer 4

If we change the factors affecting equilibrium then the reaction will shift in the direction where the effect is minimised.

Question 5

Factors Affecting Equilibrium

Answer 5

Temperature
Pressure
Concentration
Catalyst

Question 6

Temperature affecting equilibrium

Answer 6

If you increase the temperature of an already existing exothermic reaction it will become an endothermic reaction.

Question 7

Pressure

Answer 7

If you increase the pressure, the number of particles per unit volume increases.

Increasing- Equilibrium will shift where number of gaseous particles are less.

Decreasing- Equilibrium will shift where number number of gases are more.

Question 8

Concentration

Answer 8

If concentration of reactants/ if concentration of products is decreased, it will shit towards the forward direction.

Question 9

Catalyst

Answer 9

If catalyst is added, it will impact forward and backward reaction in the same manner, equilibrium will be achieved faster.

Question 10

What chemical process gives amoneia

Answer 10

Nitrogen+Hydrogen

N2 + 3H2 → 2NH3

2NH3 is amoneia

Question 11

Haber Process

Answer 11

An industrial process for producing ammonia by reaction of nitrogen with hydrogen

Question 12

Factors Affecting Haber Process

Answer 12

Temperature

Pressure

Question 13

How does temperature affect Haber’s process

Answer 13

Since the reaction is an exothermic reaction, we would need a lower temperature (450 degrees) to favour the forward reaction. However, to have a high rate of reaction we need a high temperature.

450 degrees is a compromise, low yield for high rate of reaction.

Question 14

How does pressure affect Haber’s process

Answer 14

We would need a high pressure as there are fewer molecules of product than there are reactants. We also need a high pressure for high rate of reaction

Pressure: 200atm

Question 15

Reactivity of metals

Answer 15

Metals less reactive than hydrogen:

Copper (Cu)
Silver (Ag)
Gold (Au)
Pt (Platinum)

Question 16

Reduction

Answer 16

Loss of Oxygen
Gain of Hydrogen
Gain of electrons

The substance (reactant) which reduces is the oxidizing agent/ oxidant

Question 17

Oxidation

Answer 17

Gain of Oxygen
Loss of Hydrogen
Loss of electrons

The substance which oxidizes is the reducing agent/ reductant

Question 18

More reactive metals loose electrons more ____?

Answer 18

More reactive metals loose electrons more easily

Eg.
Cu2+(aq) + Zn(s) –> Zn2+(aq)+ Cu(s)

Zn(s) –> Zn2+ + 2e- (oxidation half reaction)

Cu2+(aq) + 2e- –> Cu (reduction half reaction)

Question 19

Spectator ions

Answer 19

An ion that exists in a chemical reaction but doesn’t participate in it and remains unchanged. Spectator ions are present in the same state on both sides of the reaction

Question 20

Which all physical forms dissociate (breakdown)?

Answer 20

Only aqueous solutions will dissociate into there corresponding ions.

Gas, solid and liquid will not dissociate.

Question 21

Electrorod

Answer 21

Cathode and Anode

Cathode attracts cations (+)
Anode attracts anions (-)

Is a rod of metal or graphite through which an electric current flows into or out of an electrolyte.

Question 22

Electrolyte

Answer 22

Is the ionic compound (liquid basically) in a molten or aqueous solution that conducts electricity

Question 23

Covalent compounds electrolysis

Answer 23

They cannot conduct electricity therefore cannot undergo electrolysis

Question 24

Electrolysis

Answer 24

When an electric current is passed through a molten or aqueous solution the compound decomposes (breaks down).