chemical changes Flashcards
oxidation vs reduction
oxidation- gain of O2 and loss of electrons
reduction- loss of O2 and gain of electrons
metal + water
metl hydroxide + hydrogen
metals above carbon
metals below carbon
above carbon- electrolysis
below- reduction
metal + acid
salt + hydrogen
base vs alkali
base- pH above 7- neutralises acids- insoluble in water
alkali- solubkle in water to form alkaline solution
acid + base
salt + water
acid + metal acid
salt + water
acid + metal hydroxide
salt + water
acid + metal carbonate
salt + water + carbon dioixide
acids in water
dissociate to produce H+
akalis in water
OH-
how to test for pH
- universal indicator
- pH probe
neutralisation reaction- symbol equation
H+ (aq) + OH- (aq) -> H2O (l)
what is a strong acid
3 examples
- they dissociate fully in water
- hydrochloric acid HCl
- nitric acid HNO3
- sulfuric acid H2SO4
what is a weak acid
3 examples
- partially ionise in water- equillbrium
- ethanoic acid
- citric acid
- carbonoic acid
what is ph a measure of
concentration of hydrogen ions- the lower, the higher in scale
concentration & dilute vs strong & weak
- concentration- amount of substance in a given volume
- strong/weak- H+ ion concentration
pH scale
change of 1- change in concntration by a factor of 10
titration concentration
concenration = moles/vol(dm3)
what is electrolyte
molten ionic compound- ions free to move- can conduct electricity
process of electrolysis
- passing electric current through electroyte causing ions to move electrodes
- positve move to anode
- negative to cathode
- ions discharged at electrodes producing elements
cathode vs anode
cathode- negative- positice goes to & gains electons = metal
anode- positive- negative goes to & looses electrons = non-metal
extraction of aluminum from bauxite
- aluminium oxide from brauxite purified
- dissolved in molten cryolite as metlting point to high- cyrolite lowers mp
- carbon as positive anode
why does the anode in xrraction of carbon needs to be replaced
- carbon reacts with oxygen- co2
- wears out
