Edexel GSCE Chemistry. Metals and Equalibria

A metal with one or more other elements (usually metals) added to improve its properties.

alloy

Iron with other elements added to make an alloy.

alloy steel

A negatively charged ion, formed by gaining electrons (usually a non-metal ion).

anion

Positive electrode.

anode

Using bacteria to extract metals from their ores.

bioleaching

A substance that speeds up a process, without itself being used up.

catalyst

Negative electrode.

cathode

A positively charged ion formed by losing electrons.

cation

When substances cannot enter or leave an observed environment, e.g. a stoppered test tube.

closed system

A reaction in which a metal reacts with air and sometimes water to form a metal oxide or hydroxide.

corrosion

A substance that absorbs water or water vapour.

desiccant

In electrolysis, an ion is discharged when it gains or loses electrons to form a neutral atom or molecule.

discharged

A reaction where a more reactive element takes the place of a less reactive element in a compound.

displacement reaction

A substance that can be stretched out to make a thin wire.

ductile

When the forwards and backwards reactions in a reversible chemical reaction are occurring at the same rate.

dynamic equilibrium

A rod made of a metal or graphite that carries the current into or out of the electrolyte.

electrode

A process in which electrical energy from a direct current supply decomposes electrolytes.

electrolysis

An ionic compound that is molten or dissolved in water.

electrolyte

Using electricity to coat one metal with a thin layer of another metal.

electroplating

A type of reaction in which energy from the surroundings is transferred to the products, photosynthesis

endothermic

A type of reaction in which energy is transferred to the surroundings from the reactants, e.g. combustion.

exothermic

A process in which a metal is obtained from its ore.

extraction

Coating iron or steel with a thin layer of zinc to improve its resistance to rusting.

galvanising

Ionic equation showing electron transfers in oxidation or reduction.

half equation

An electrode that is unreactive, such as graphite or platinum.

inert

A solution produced when water or another solvent passes through a mixture of substances and dissolves some of them.

leachate

A technique used to assess the environmental impact associated with all the stages in the life of a product from cradle to grave.

life cycle assessment (LCA)

A substance that can be hammered or rolled into shape without shattering.

malleable

A metal that occurs uncombined with any other element.

native state

A system into or from which substances can enter or leave, such as a reaction inside an open test tube.

open system

A rock that contains a high concentration of a metal or metal compound.

ore

A reaction in which oxygen is added to a chemical substance; loss of electrons by an atom or negative ion.

oxidation

To gain oxygen in a chemical reaction, or to lose electrons.

oxidise

Using plants to extract metals from their ores.

phytoextraction

A list of metals in order of reactivity with the most reactive at the top.

reactivity series

Converting waste materials into new products.

recycling

A reaction in which reduction and oxidation take place.

redox

A reaction in which oxidation and reduction take place.

redox reaction

A reaction in which oxygen is lost by a chemical substance; gain of electrons by an atom or negative ion.

reduction

A chemical reaction that can work in both directions.

reversible reaction

The corrosion of iron or steel. (Water and oxygen must be present for rusting to occur.) The reaction between iron, air and water to form hydrated iron (III) oxide rust.

rusting

Using a more reactive metal to protect iron from rusting.

sacrificial protection

Ions that do not change during a reaction.

spectator ions

Alloy steel containing elements such as chromium, to resist rusting.

stainless steel

A thin layer that forms on a metal due to oxidation. A metal is also said to tarnish as this layer forms.

tarnish

Metal element in the block between groups 2 and 3 in the periodic table.

transition metal