chemical reactions Flashcards
what is oxidation
when the metal gains oxygen or the loss of electrons
what is reduction
when a compound loses it oxygen or the gain of electrons
what happens when a metal reacts with water
it gives off the salt being the metal hydroxide and hydrogen
what does the reactivity of a metal depend on
it depends on how easily they lose an electron. This could be due to different factors such as inter molecular forces of attraction or amount of electrons in outermost shell
when will a metal be displaced from its compound
when it is reacted with a more reactive element ( a more reactive element will displace a less reactive element )
what is an aqueous solution
aqueous mean dissolved in water
what is an acid
an acid ionizes in an aqueous solution to form hydrogen ions
what is a base
a base is a chemical that can neutralise an acid producing a salt and water and are usually metal oxides or metal hydroxides
what is an alkali
a base the is soluble in water
an alkali ionizes to produces OH- ions in an aqueous solution
what is a neutralization reaction
when the h+ ions react with OH- ions to form water
and a neutral
acid + alkali –> salt + water
what are the 3 main acids in chemistry
HCl hydrochloric acid
H2SO4 sulfuric acid
HNO3 nitric acid
all acids contain hydrogen
what happens when an acid reacts with a metal
acid + metal –> salt + hydrogen
what ions do salts contain
the negative ion comes from the acid and the positive ion comes from the base or alkali
what happens when an acid reacts with a metal carbonate
it produces a salt water and carbon dioxide
what happens when an acid reacts with a metal carbonate
it produces a salt water and carbon dioxide
why can we not react copper with sulfuric acid to form copper sulphate
copper is too unreactive
how would you conduct a practical to make copper sulfate crystals
add a fixed volume off sulfuric acid to be the limiting reactant then heat the acid to nearly boiling so it doesn’t bubble over. slowly add in copper oxide until some is left visible at the bottom then filter unreacted copper oxide then conduct crystallization
what is a strong acid
they fully ionize to from H+ ions for example hydrochloric acid, sulfuric acid, nitric acid
what is a weak acid
a weak acid does not fully ionize to form H+ ions as it is a reversible reaction for example carbonic acid, ethanoic acid, citric acid
what is a weak acid
a weak acid does not fully ionize to form H+ ions as it is a reversible reaction for example carbonic acid, ethanoic acid, citric acid
as the pH goes down by one what happens to the concentration of H+ ions
they increase by 10x or one order of magnitude
what do we call the natural curve that a liquid has
the meniscus
what is the formula for number of moles regarding concentration and volume
number of moles = concentration (mol/dm³) * volume (dm³)
how do you get from mol/dm³ to g/dm³
multiply by the relative formula mass
how do you get from mol/dm³ to g/dm³
multiply by the relative formula mass
why does the electrolyte in electrolysis have to be molten or dissolved in water
because in solids ions are not free to move
what are the electrodes made of
usually graphite as it can conduct electricity
what happens at the negative electrode
the metal is attracted to the negative electrode and gains electrons which is an example of a reduction reaction
what happens at the negative electrode
the non metal is attracted to the negative electrode and loses electrons which is an example of a reduction reaction. group 7 elements will for diatomic particles so the half equation will look different
why is aluminium oxide mixed with a cryolite
a cryolite is substance that reduces the boiling point of the aluminum so electrolysis will require less energy
why should the anode be regularly replaced
the oxygen car react with the graphite (made of carbon) to form carbon dioxide
why is electrolysis expensive
because melting the compound requires a lot of energy and a lot of energy is needed to produce the electric current
what do water molecules ionize into
the split into H+ ions and OH- ions
what happens at the cathode in a aqueous solution
if the metal is more reactive than hydrogen then hydrogen forms instead of the metal
what does inert mean
unreactive
what is the half equation for the reaction at the anode in an aqueous solution
4OH- = O2 + 2H2O = 4e-
what is the exception to oxygen being produced at the anode in an aqueous solution
if the gas is a halide ion it will be produced instead of the oxygen
