Reversible Reactions
Manufacture of Sulfuric Acid
•Know and describe the stages in the contact process
for the manufacture of sulfuric acid
•Know that vanadium (V) oxide is used a catalyst
Bread
Toast
I wonder what conditions would
affect these reactions?
H2O (s)
Water
Solid Wax
H2O (L)
Click on the thinking
cloud to highlight the
equilibrium sign
Ice
Click on the detective
twice
Liquid Wax
Click on the reactants
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instructions
I can’t quite
guess what
that symbol
means!
mmm.. My new
task is in this
letter. Well lets
open it up and
start on the first
clue....
Click on the letter
twice
Click on the detective
• Sulfuric acid has many uses in
industry.
• The amount of sulfuric acid which
a country uses in one year
can be a measure of that
country's economic development
(how modern or wealthy it is).
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Well without
Watson even I
know my task is
to find out about
the manufacture
of sulfuric acid ...
Click on the Watson..
air balloon
and then on the piece
of sulfur
Click the speech (I
have the following) –
click twice
Click the slide
anywhere until the
speech (I
have...)appears
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instructions
Detective...
I have the following
raw materials for you
to identify..
1. Sulfur found in Fossil Fuels...
Sulfur + oxygen
S(s) + O2(g)
sulfur dioxide
SO2(g)
Great, well don’t wait
for me lets see what
happens...
Not yet. We still have
to balance the
equation..
When sulfur in fossil
fuels is burned it
produces sulfur
dioxide gas.
Write a
sentence
to
describe
the
reaction
Write a
Balanced
Equation
I have the Raw
materials for you
detective
Success!
Can you describe this
detective
2. Sulfur Ores
... Sulfide ores are heated in air
to produce the metal oxide and sulfur
dioxide gas, for example..
Can you
finish the
reaction..
Can you
balance
the
reaction..
lead sulfide + oxygen
lead oxide + sulfur dioxide.
2PbS(s) + 3O2(g
2PbO(s) + 2SO2(g)
Is there another way
to make sulfur
dioxide?
Yes,....
Sulfur is oxidised in
the previous reactions
to become sulfur
dioxide.
Both reactions are
exothermic.
There are conditions
for this reaction...
sulfur dioxide + oxygen
2SO2(g) + O2(g)
The sulfur dioxide
gas produced from
both of the above
methods
is used to make
sulfur trioxide
sulfur trioxide.
2SO3(g)
And don’t forget that a catalyst is used
called.... Vanadium (V) oxide
But
a)what is Exothermic
b) How is the sulfur dioxide used
Write a balanced
equation for the
reaction..
What does that sign
mean! Does it effect
the reaction
An increase in temperature is used to speed
up chemical reactions but it can have an
undesired effect when the reaction is
reversible and exothermic.
Vanadium
(V) oxide
In many industrial processes a
compromise temperature is
used . To reduce the problem
one must look for a way of
increasing the rate of a reaction
without decreasing the yield
i.e. with a catalyst.
This is the sign for a reversible
reaction. Pressure and
temperature will have a big impact
on the product yield, so in a
reversible reaction it is very
important to get it right!
WATSON! Stop daydreaming, I
am about to explain the sign at
the centre of our investigation... I
mean reaction!
The Contact Process:
A brief summary of the Contact Process
converts the
sulphur
dioxide
into...
makes s....
....concentrated
sulphuric acid.
... sulphur trioxide
(the reversible
reaction at the heart
of the process);
...ulfur dioxide
converts the sulphur
trioxide into....
To make this more
difficult you could just
show the starter
sentence
Pupils must join up the
correct start to the
sentence with the
correct end
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instructions
Chemistry really is a
lot of fun!!