Simple
problems in Chemistry
1) Hydrochloric acid is neutralised
by sodium hydroxide according to the following equation:
HCl + NaOH ® H2O
+ NaCl
An experimenter starts off with 100kg of hydrochloric
acid.
a) How many moles of Hydrochloric acid
are present in 100kg ?
b) How much sodium hydroxide is required
to neutralise 100kg of hydrochloric acid ?
2) Water reacts with carbon dioxide to
give a weak acid called carbonic acid. Assume the
following
chemical equation:
H2O + CO2 ®
H2CO3
a) How much carbonic acid will 250kg
of carbon dioxide produce ?
b) How many moles of carbon dioxide
are present in 250kg of this gas ?
c) How many moles of carbonic acid
are produced ?
d) What mass of water reacts with 250kg
of carbon dioxide ?
e) How many moles of water are produced
during this reaction ?
3) Sulphur trioxide in the atmosphere reacts
with water vapour to produce sulphuric acid.
Assume the
following chemical reaction:
SO3 + H2O ®
H2SO4
a) What mass of sulphur trioxide is
required to produce 150kg of sulphuric acid ?
b) How many moles of sulphuric acid
are contained in 150kg of this chemical ?
c) How many moles of sulphur trioxide
are required to produce 150kg sulphuric acid ?
d) What mass of water reacts with sulphur
trioxide ?
e) How many moles of water are produced
during this reaction ?
4) Methane is oxidised in the following
reaction:
CH4 + OH- ®
CH3- + H2O
a) What mass of water is produced by
200kg of methane ?
b) How many moles of methane are present
in 200kg ?
c) How many moles of methane are present
in 200g
d) How many moles of water are produced
by 200kg of methane ?
5) Nitric acid in the atmosphere is produced
by the following reaction:
NO2 + OH- ®
HNO3
a) What mass of nitric acid is produced
by 10kg of nitrogen dioxide?
b) How many moles of nitrogen dioxide
are present in 10kg ?
c) How many moles of nitrogen dioxide
are present in 10g ?
d) How many moles of nitric acid are
produced during this reaction ?
(relative atomic masses in g mol-1: H=1,
Cl=35.5, Na=23, O=16, N=14, C=12, S=32)