electrolysis Flashcards
(26 cards)
what are positive electrodes made of?
graphite
what are negative electrodes made of?
graphite
why temp has to be high if aluminium oxide was used?
high melting points
how is operating temp kept low electrolyse
aluminium oxide is dissolved and mixed with cryolite
what type of reaction happened at negative electrodes
reduction
what type of reaction happen at positive electrodes
oxidation
two proxies of aluminium that makes it suitable?
low density and malleable
which side is positive and negative for electrodes
left os cathode right is anode
what is a cathode
negative electrode
what is an anode
postive electrode
what does cryolite do?
loweres the melting point
why is carbon monoxide poinisous
binds to hameogoblin limiting oxygen transportation
when is hydrogen gas produced
when metal is more reactive than hydrogen
when is a pure metal solid layer produced
when it is less reactive than hydrogen
(d) Magnesium oxide can be used to make magnesium sulfate by this reaction. MgO(s) + H2SO4(aq) - a student is provided with a beaker of dilute sulfric acid outline the steps she could take to obtain a pure sample of hydrated magnesium sulphate crysltrals using this reaction
mix two substances use excess of powder filter heat to remove some water leave to crystallise
add damp blue litmus paper chlorine
turns red then bleches
bubble chlorine into a solution of potassium iodine
black precipitate
suggest why the volume of chlorine is less than expected
it is soluble in water
why the phenolphatlin turns pink
it is alkaline so OH- is formed
why is chlorine added to water
to sterilise the water
what is meant by the term electrolysis
splitting by electricity
suggest a suitable metal for inert electrodes
platinum
what is electrolyte
a molten ionic compound that an electric current is passed through causing it to decompose
what would you expect to see at the anode of inert electrons
bubbles of the negative ion
