14.1 Metal ores and metal extraction

Metal ores and metal extraction

We get metal from:

rocks in earth’s crust

Hard outer skin of Earth

Crust

Rock is mixture of:

substances

Earth’s crust is almost half:

oxygen

Oxygen and silicon in Earth’s crust are found in:

Silicon (IV) oxide

oxygen in Earth’s crust is found in

metal oxides and carbonates

Most abundant metal in Earth’s crust

aluminum

The rocks from which we obtain metals from

ores

Ore of iron

Hermatite

Hermatite is mostly:

Iron (III) oxide

Aluminum ore

Bauxite

Bauxite is mostly:

Aluminum oxide

3 examples of ores

hermatite, bauxite, gold

Extracting a metal from an ore depends on:

The metal’s reactivity

Most metals in ores occur as:

compounds

How to reduce metal compound to metal

Through chemical reaction

Reduction

Loss of oxygen or gain of electrons

compounds of more reactive metals are:

stable

How to reduce compounds of reactive metals

electrolysis

Why is electrolysis expensive?

Needs lots of electricity

Compounds of less reactive metals are:

less stable

How to reduce compounds of less reactive metals

Heating with suitable reactant

Why is reduction not needed for silver and gold

Occur naturally as elements

Why is carbon monoxide used when heating for extraction

carbon reacts with little oxygen to give carbon monoxide gas which brings reduction