unit 5 Flashcards
base
used to neautralise -metal oxides
calcium oxide
used to neutralize acidic soil
when acid ionises-
when alkali ionises-
produces H+
produces OH
alkali+water
water and salt
metals form
basic oxides and hydroxides
non metals form
acidic oxides
alumina
aluminium reacted with oxygen found in mineral bauxite
extracted and purified using bayar process
stages of bayar process
crush bauxite
filter impurities
allow to crystalize to form alumina
neutralize nitric acid
using calcium hydroxide
extraction of alumina
molten alumina is electrolysed using haul haroult process
croyolite
is added to lower melting point and save energy
electrolysis
spliting chemicals into their elements by passing electrical current
diaphram cell
porous so it allows brine to pass from one side to another but prevents chlorine and hydrogen gas from passing through so gasous produts are kept separated but still mixed with brine
membrane cell
has an ion exchange membrane diving the cell .allows posituve ions but wont allow negative to pass through from the anode to catode as the brine only enter the cell the from the anode
why is sodium hydroxide formed at the membrane cell more purified than diaphragm cell
contaminated with sodium chloride