CC11 - Obtaining and using materials

Products of potassium and cold water

Potassium hydroxide and hydrogen

How to ensure magnesium reacts with H2O?

Use steam

Why is potassium more reactive than iron?

Greater tendency to lose electrons and form cations.

Why are displacement reactions classed as redox reaction?

The reactive metal is oxidised and the less reactive metal is reduced.

Half equation of zinc oxidation

Zen → Zn2+ + 2e-

Ore

A rock that contains enough of a compound to extract a metal for profit.

How to extract group 1/2/3 metals from their ores?

Electrolysis

How to extract transition metals from their ores?

Heating with carbon ( in a blast furnace)

Biggest disadvantage of electrolysis

Large amounts of CO2 produced from burning of fossil fuels.

Main advantage and disadvantage of bioleaching

Much more energy efficient, but slow.

Main advantage and disadvantage of phytomining

Can extract metals from contaminated and low quality ores in soil, but growing plata is weather dependent and the products still need electrolysis to be pure.

How does cryolite help electrolysis of aluminium oxide?

Reduce melting point of aluminium oxide

In this equation Wya has been reduced or oxidised:

PbO + C → Pb + CO2

PbO reduced and C oxidised

Advantage of recycling metals

We are running out of new ores

Disadvantages of recycling

Transporting, cleaning, sorting, all these involve energy

4 stages of life cycle assessments

Obtaining raw materials, manufacture, use and disposal.

What is considered in an LCA?

Energy costs, water use, lifespan, sustainability, disposal method, carbon footprint.