Metals above carbon in the reactivity series

State why magnesium cannot be extracted from its oxide by reduction with carbon.

The extraction of aluminium involves the use of an electrolytic cell.

A factory uses 18,000 kWh of electricity to extract 1 tonne of aluminium by electrolysis, while producing 1 tonne of iron by reduction with carbon uses 800 kWh. Calculate how many times more electricity is used to produce 1 tonne of aluminium than 1 tonne of iron. Give your answer to the nearest whole number.

Manganese (a metal) can be extracted from its oxide, MnO2, by heating with aluminium powder. Explain why manganese can be extracted this way, and what this shows about its position in the reactivity series.

State why copper, which is above carbon in the reactivity series, cannot be extracted from copper(II) oxide by heating with carbon.

The diagram shows the extraction of aluminium from aluminium oxide.

Aluminium oxide is dissolved in molten cryolite and electrolysed.

A company is deciding whether to extract a metal by carbon reduction or electrolysis. It costs £70 to make 1 tonne of metal using carbon reduction and £780 to make 1 tonne of aluminium using electrolysis.

Calculate how much more expensive it is to produce aluminium by electrolysis rather than using carbon reduction.