Chemistry paper 1

Question 1

what are the properties of transition metals

Answer 1

• hard, strong, shiny and malleable
• conduct heat and electricity well
• high melting and boiling points
• high densities
• corrosion resistance mostly

Question 2

bronze = copper + tin

Answer 2

bronze is harder than copper

it’s used to make medals, decorative ornaments and statues

Question 3

brass = copper + zinc

Answer 3

brass is more malleable than bronze and is used in situations where lower friction is required such as in water taps and door fittings

Question 4

gold alloys are used to make jewellery

Answer 4

pure gold is very soft and malleable
metals such as zinc and copper are silver are used to strengthen the gold
pure gold is described as 24 carat so 18 carats means that 18 out of 24 parts of the alloy are pure gold
in other words 18 carat gold is 75% gold.
for example an 18 carat gold ring with a mass of 20g contains 20 x (18/24) - 15g of gold

Question 5

aluminium alloys are used to make aircrafts

Answer 5

aluminium has a low density which is an important property in aircraft manufacture. But pure aluminium is not strong enough for making aeroplanes so it’s alloyed with amounts of other metals to increase its strength

Question 6

magnalium = aluminum + magnesium

Answer 6

when it’s made with small amounts of magnesium (about 5%) magnalium is stronger, lighter and corrodes less easily than pure aluminium.
this type of magnesium is used to make parts for cars and aeroplanes
magnalium with a higher magnesium content (about 50%) is used in fireworks as it’s reactive and burns brightly like magnesium but us more stable than pure magnesium

Question 7

what is the rusting of iron

Answer 7

a redox reaction

Question 8

discuss rusting/corrosion

Answer 8

metals can corrode in the presence of oxygen and water to form h