CHEMICAL CHANGES Flashcards
What are the two ways you can test the ph of a solution
universal indicator and a ph probe
what does a ph probe give you the ph as
an numerical value
when acids dissolve in water what do they form
H+ ions
when alkalis dissolve in water what do they from
OH- ions
what is the neutralisation equation
acid + Base ——– salt + water
acid + base =
salt + water
neutralisation symbol equation
(H+) + OH- —— H2O
what does an acid and an alkali make
water which is neutral
when a acid neutralises a base the products are…..
neutral
strong acids…
fully ionise in water
in strong acids all acid particles….
dissociate to release H+ ions
examples of strong acids
sulfuric acid, hydrochloric acid and nitric acid
weak acids…
partially ionise in water
in weak acids…. (particles)
only a small amount of acid particles dissociate to release H+ ions
examples of weak acids
ethanoic, citric and carbonic
symbol for hydrochloric acid
HCL
symbol for nitric acid
HNO3
symbol for sulfuric acid
H2SO4
pH is a measure of….
the concentration of H+ ions
acid + metal oxide =
salt + water
acid + metal hydroxide =
salt + water
acid + metal carbonate =
salt + water + carbon dioxide
acid + metal base =
salt + water
mnemonic for the reactivity series
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acid + metal =
salt + hydrogen
metal + water =
metal hydroxide + hydrogen`
what is oxidation in terms of oxygen
gain of oxygen
what is reduction in terms of oxygen
loss of oxygen
what metals can be extracted by reduction using carbon
metals below carbon in the reactivity series
how are metals extracted from their ores by reduction with carbon
the ore is reduced as oxygen is removed from it, and carbon gains oxygen so is oxidised
what metals can be extracted by using electrolysis
metals higher than carbon in the reactivity series
what is oxidation in terms of electrons
oxidation is the loss of electrons
what is reduction in terms of electrons
reduction is gain of electrons
mnemonic for oxidation and reduction in terms of electrons
OILRIG
OXIDATION IS LOSS REDUCTION IS GAIN
What is a displacement reaction
a more reactive metal will displace a less reactive metal from its compound
where is lithium on the periodic table
underneath sodium
what is an electrolyte
is a liquid or solution that can conduct electricity
what are the two electrodes
anode and cathode
where do the positive ions in an electrolyte move to? and what happens there
the cathode where they are reduced
where do the negative ions in an electrolyte move to? and what happens there
the anode where they are oxidised
in electrolysis of aqueous solutions what happens at the anode
if halide ions are present a halogen will be formed
if no halide ions are present oxygen will be formed
in electrolysis of aqueous solutions what happens at the cathode
if the metal is more reactive than hydrogen ,, hydrogen will form
if the metal is less reactive than hydrogen,, the metal will form
at the cathode does it lose or gain electrons?
gain electrons
at the anode does it lose or gain electrons?
lose electrons
in half equations for redox reactions if the electrons are on the right hand side it is
oxidation
in half equations for redox reactions if the electrons are on the left hand side it is
reduction
at the anode is it oxidation or reduction
oxidation
at the cathode is it oxidation or reduction
reduction
Sodium is one of the most abundant metals on Earth. Explain, as fully as you can, why sodium was not extracted until 1807.
sodium is very reactive
have to use electrolysis to remove it,
explain why an acid can be described as both strong and dilute
can be called strong acid because it is completlely ionised but can be called dilute because small amount of acid per unit volume
