Name ______________________________________________
10. Did any atoms get destroyed during the reaction?
Carbonate Decomposition
11. Did any atoms turn into another kind of atom during the reaction?
Most carbonates decompose like this when heated:
CaCO3  CaO + CO2↑
12. Write a balanced equation for the reaction that actually happened
in this experiment.
The lost CO2 accounts for weight loss.
Experimental procedure:
You will be provided with a white powder, which could be lead
carbonate, barium carbonate, zinc carbonate, or magnesium carbonate.
You will heat it strongly for about five minutes and determine the %
weight loss.
13. Starting with the mass of the powder before heating (#3), calculate
the theoretical yield of carbon dioxide that should have been
produced. (Show all calculations!)
mass in grams
1
weight of the crucible
2
weight of the crucible + the powder
3
weight of just the powder
4
crucible + powder after heating
5
just the powder after heating
6
weight loss of the powder
7
% mass loss of the powder
(mass lost/ initial mass) X 100
14. What mass of CO2 was actually produced?
15. Was the actual mass of CO2 that escaped the reaction (#14) higher
or lower than the calculated (theoretical) mass of CO2 (#13)?
16. What could account for the difference between the calculated
(theoretical) value and the experimental (actual) value?
8. Circle the identity of the carbonate you started with:
PbCO3 = 16% CO2
BaCO3 = 22% CO2
ZnCO3 = 35% CO2
MgCO3 = 52% CO2
9. Why did the powder lose mass during the heating process?
17. How many molecules of CO2 escaped into the air from your
reaction? Show all work!