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Chemistry IGCSE
Chemistry, 12: Sulfur
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Cards (11)
What are the uses of sulfur?
Oil
refining
Fertiliser
Paper
and
steel
making
Acid
in car batteries
How is sulfur produced?
The
contact
process
What are the sources of sulfur?
Underground bedrock
Volcanic deposits
Describe the contact process:
Sulfur +
oxygen
is used to make
sulfur dioxide
Sulfur dioxide is converted into
sulfur trioxide
by reacting with more
oxygen
(reversible)
Sulfur trioxide
+
sulfuric acid
creates concentrated sulfuric acid (oleum)
Oleum +
water
creates
sulfuric acid
Why do you need to make oleum?
Adding
sulfur trioxide
directly into water would be extremely exothermic and create
acid mist
What are the conditions for the contact process?
Catalyst-
vanadium oxide (
V2O6
)
Temperature-
450C
Pressure-
2atm
The highest yield of sulfur trioxide would be made at
low
temperatures, which is too slow therefore
450C
is used
High pressure
is not used as the yield is
98
%
Unconverted
reactants are
recycled
What are the equations involved in the contact process?
S + O2 ->
SO2
2SO2
+ O2 ⇌
SO3
H2SO4 +
SO3
->
H2S2O7
H2S2O7
+ H2O ->
2H2SO4
Oleum
is
highly
corrosive
It is a
dehydrating
agent
, absorbing
hydrogen
and
oxygen
from compounds in the form of
water.
When
oleum
is added to
glucose
, carbon is formed
The reaction is highly
exothermic
, and
steam
is produced
A honeycomb structure of black carbon is also formed