Thermal Decomposition of Group 2 Carbonates
Aim: Describe the thermal decomposition of the carbonates of elements in group 2 and the
trend in their ease of decomposition.
Method: A selection of group 2 carbonates were heated strongly for 5 minutes. Their mass
was recorded before and after heating so that any change could be calculated. Any gas
produced was bubbled through limewater and the time taken for the limewater to turn
cloudy was recorded.
Results:
Carbonate
Mass after
Heating (grams)
2.2
2.1
never
2.2
1.05
40
2.0
1.36
240
2.1
1.09
70
Barium
Carbonate
Magnesium
Carbonate
Strontium
Carbonate
Calcium
Carbonate
Change in Mass
(grams)
Time Taken for
Limewater to go
Cloudy (seconds)
Mass before
Heating (grams)
Conclusion: Use the results above to form a conclusion.
Questions to consider:
1) What is the change in mass for each carbonate?
2) What is the trend in thermal stability down the group?
3) What is the trend in thermal decomposition down the group?
4) What is the general symbol equation for the reaction?
5) What could these carbonate be used for?
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Reactions of Group 2 Elements
Aim: Describe the redox reactions of the Group 2 elements Magnesium  Barium with
oxygen and with water. Explain the trend in reactivity of Group 2 elements down the group in
terms of atomic size, shielding and nuclear attraction.
Group 2 Element
Observations of the
Reaction with Oxygen
Observation of the Reaction
with Water
Magnesium
Calcium
Strontium
Barium
Use your observations to state the trend in reactivity as you go down group 2.
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Explain this trend in terms of atomic size, shielding and nuclear attraction.
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Write a general symbol equation for the reaction of a group 2 metal with oxygen
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Write a general symbol equation for the reaction of a group 2 metal with oxygen
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