Chemical Changes

Created by

Freya

Cards (31)

Redox reactions involve the transfer of electrons between reactants, resulting in a change in oxidation states.
Metal + water -> metal hydroxide + water
when metals react they lose electrons and form a positive ion
when a metal reacts with oxygen it forms a metal oxide
OILRIG- Oxidation is loss of electrons and Reduction is gain of electrons
A more reactive element will displace a less reactive element from a compound
Metals less reactive than carbon can be extracted from their oxides using reduction with carbon
metals more reactive than carbon must be extracted using electrolysis
an aqueous solution means dissolved in water
In aqueous solutions, acids produce hydrogen ions
Bases are chemicals that can neutralise acids , producing salt and water
some bases can be alkalis but not all
In aqueous solutions, alkalis produce hydroxide ions
Acid + Alkali -> water
2HCL + Fe -> FeCl2 + H
Fe -> Fe2+ + 2e- (oxidation)
2h+ + 2e- -> H2 (reduction)
Acid + metal -> salt + hydrogen
Electrolysis is the process of being split into ions by passing an electric current through a solution
salt contains a positive ion from the base and a negative ion from the acid
metal carbonate + acid -> salt + water + carbon dioxide
in aqueous solution acid molecules ionise (split) and release H+
strong acids fully ionise in aq
weak acids partially ionise and are reversible reactions with aq
Strong acids have a lower PH than weak acids for a given concentration of H+ ions
as ph scale decreases by one unit, the concentration of H+ increases by x10
electrolytes are ions that are dissolved in liquid and can conduct electricty
anions are negatively charged ions
cations are positively charged ions
cathode: the negatively charged electrode in a cell, where electrons are lost
anode: the positively charged electrode
Ion Groups
Group One : 1+
Group two: 2+
Group three: 3+
Group five: 3-
Group six : 2-
Group seven: 1-
(aq) means water is also present so you have H+ and OH- ions in the solution