C4 Flashcards
whats an acid
a substance that forms H+ ions in aqueous soloutions
whats an alkali
a soluble base that forms OH- ions in soloution
what is the pH scale
a scale from 0-14 that measures how acidic or alkaline a soloution is
what pH value is neutral
pH 7
what does low pH mean
soloutions acidic
what does a high pH mean
soloution is alkaline
whats a base
a substance that can neutralize an acid
what is a neutralization reaction
acid + base -> salt + water
what happens when acid reacts with metal
metal + acid -> salt + hydrogen
what test is used to identify hydrogen
squeaky pop
what happens when acids react with metal carbonates
acid + metal carbonate -> salt + water + CO2
test for CO2
limewater-turns cloudy
whats a strong acid
completely ionises in water
whats a weak acid
only partially ionises in water
difference between strength and concentration of an acid
strength-degree of ionisation
concentration-amount of acid in a volume of soloution
whats electrolysis
the breakdown of a substance by using electricity
whats the electrolyte
the ionic compound thats broken down during electrolysis
what happens at the cathode
positive ions gain electrons
what happens at the anode
negative ions loose electrons
whats the rule for electrolysis of aqueous soloutions at the cathode
hydrogen is produced if the metal is more reactive than hydrogen
whats the rule for electrolysis of aqueous soloutions at the anode
oxygens produced unless halide ions are present, then the halogen is produced
whats oxidization
loss of electrons
whats reduction
gain of electrons
mnemonic for redox reactions
Oxidation
Is
Loss
Reduction
Is
Gain
whats an example of a redox reaction in chemical changes
displacment of less reactive metals by more reactive ones
