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Aim: To find the unknown metal in a metal carbonate
Instructions
- Accurately weigh out about 0.25g of the unknown metal carbonate MCO3
- React this with hydrochloric acid and collect the gas produced
- As 1 mole of metal carbonate makes one mole of CO2 gas calculate the
identity of the unknown metal
MCO3 + 2HCl 
MCl2 + H2O + CO2
You must perform this experiment using both of the described methods
Method 1
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You must try to arrange your apparatus so that the two reactants
(the metal carbonate and the hydrochloric acid ) can be mixed together
AFTER the apparatus is assembled and sealed. This will require a
certain degree of thought - you can ask for extra pieces of apparatus
if you think that it could help
Also, do not forget to take into account the air that gets displaced
when the rubber bung is pushed into the side-arm tube
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Assembled apparatus (the delivery tube does not really
go through the bottom of the trough!)
This method of gas collection is called "downward
displacement of water"
In your experiment you will be usiong an upside down
burette and not a graduated cylinder.
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Method 2
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Try to arrange your apparatus so that the two reactants (the metal
carbonate and the hydrochloric acid ) can be mixed together AFTER
the apparatus is assembled and sealed. This will require a certain
degree of thought - you can ask for extra pieces of apparatus if
you think that it could help
Also, do not forget to take into account the air that gets displaced
when the rubber bung is pushed into the side-arm tube
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Using the gas syringe
The gas syringe MUST be clean and dry before you start
or the plunger will not be pushed out smoothly by the gas.
Do not allow the gas to completely push out the plunger
(release the rubber bung from the apparatus if this looks likely
to happen)
In your experiment you will be using a side-arm tube
and not a conical flask
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Write-up
Aim - What you are trying to find out
Hypothesis - which metal carbonate could it be and why?
Method - a clear description with an accurate 2D diagram in pencil using
a ruler
Results- Record and analyse all of the necessary data (include inaccuracies
where you can state or assess them)
Conclusions - Which metal is in the carbonate and why
Evaluation - Compare and contrast the accuracy of the two methods and
discuss where the accuracy could be improved
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