Chapter 4 - Extracting Metals and Equilibria Flashcards Preview

Chemistry > Chapter 4 - Extracting Metals and Equilibria > Flashcards

Flashcards in Chapter 4 - Extracting Metals and Equilibria Deck (32):
1

Reactivity series.

Potassium, Sodium, Calcium, Magnesium, Aluminum, CARBON, Zinc, Iron, HYDROGEN, Copper, Silver, Gold

2

Below hydrogen on series

Doesn’t react with dilute acids

3

Metals at the top

More easily oxidise to form cations.

4

Testing reactivity

Add metals to acid, perform squeaky pop test. The louder the more reactive as reaction rate is higher meaning more H2 per second.

5

Metal + water
(Reactive metals)
Metal + steam
(Less reactive)

Metal Hydroxide + Hydrogen

Metal Oxide + Hydrogen

6

Displacement reactions are examples of..

REDOX reactions.
More reactive - oxidation
Less reactive - reduced

7

Displacement reactions define

More reactive metals take the place of less reactive metals

8

Metals are found in

Ores

9

Aluminium ore

Bauxite Al2O3

10

What can be extracted using carbon?

Metals less reactive than iron can be reduced in a blast furnace.

11

Metals more reactive carbon must be extracted using

Electrolysis

12

Why electrolysis is expensive

Large amounts of electricity is expensive.
If the ore must be melted

Reduction with carbon is cheaper as carbon is cheap and fuels the heat in an exothermic reaction

13

Bioleaching

Uses bacteria to separate metals from ores. Bacteria carry out chemical reactions and form a leachate, contains high concentration of metals. This can be extracted using electrolysis or displacement.

14

Phytoextraction

Plants grown on soil with metal compounds. They are taken up and build up in tissue. They are burned forming ash with metals, extracted using electrolysis or displacement

15

Recycling positives

Prevents finite resources running out
Saves more energy than original extraction
Mines are damaging to environment and destroy habitat.
Reduces landfill.

16

Economic benefits of extraction

Extracting costs more than recycling.
Creates jobs

17

Life Cycle Assesment

LCA , looks at every stage of the lifetime of a product

18

LCA: Choice of material

Metals must be mined and extracted requiring energy, releasing pollution .
Crude oil is non-renewable and requires lots of energy in extraction

19

LCA: Manufacturing

Uses lots of energy
Causes pollution
Waste may be poorly disposed
Often require water, contaminated water may be let out.

20

LCA: Product Use

Burning fuels releases

Fertilisers can leach into water causing damage to ecosystem.

21

LCA: Disposal

May be disposed in Landfill, polluting land and water.

Products may be incinerated causes air pollution.

22

Haber process equation

N2 + 3H2 2NH3

23

Haber process temperature, pressure and catalyst

450C,
200 atmospheres
Iron catalyst

24

Dynamic equilibrium

The forward and backward reactions are happening at the same rate and time. Concentrations have reached a balance so won’t change.

25

Equilibrium can only be reached in a

Closed System

26

Equilibrium shifts right

More products (concentration) less reactant (concentration)

27

Equilibrium shifts left

More reactant (concentration) Less products (concentration)

28

What 3 things can change the position of equilibria.

Temperature,
Pressure (involving gases)
Concentrations (reactants or products)

29

Effect of temperature on equilibria.

Increase : Moves ENDOthermic direction.
Decrease: Moves EXOthermic direction

30

Le Chatelier principle

If the concentration, temperature or pressure change, the reaction will shift to COUNTERACT this.

31

Changing pressure on equilibria

Increasing: Moves side with few moles of GAS
Decreasing: Moves to side with more moles of GAS

32

Changing concentration on equilibria

Increase REACTANTS: Shifts right, to use up the added reactants.

Increase PRODUCTS: Shifts Left to use up the added products.

Decreasing has the OPPOSITE effect.