The combustion of elements in oxygen
3 marks · EasyThe apparatus below is used to burn phosphorus in air:
State the name of the gas in air that phosphorus reacts with when it is burned.
Give one observation you would make when phosphorus burns in air.
Name the compound formed when phosphorus combusts in oxygen.
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(a) oxygen
(b) white smoke forms · must show observation, e.g. white fumes, smoke, or similar
(c) phosphorus oxide
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States 'oxygen' as the gas in air that reacts with phosphorus
B1 (b) · 1 mark · Gives a correct observation: e.g., white smoke/fumes produced or similar
B1 (c) · 1 mark · Names the compound formed as 'phosphorus oxide'
Worked solution
a) The gas that reacts is oxygen. b) You see white smoke or white fumes inside the bell jar. c) The compound formed is phosphorus oxide.