Pre-lab Questions
1. Michelangelo used fresco painting when he painted the Sistine Chapel. Fresco painting involves most of the types of chemical reactions you just studied. Listed below are some of the reactions used in creating a Fresco painting. Identify the type of chemical reaction used for each step and balance the chemical equation if needed. Initially, some sort of heat must be generated. Propane is an example of a common fuel source used for heating.
C3H8 + O2 → CO2 + H2O
This is a reaction
Next, quicklime (calcium oxide) is made by roasting calcium carbonate (limestone).
CaCO3 → CaO + CO2
This is a reaction.
The quicklime is slaked to form lime plaster.
CaO + H2O → Ca(OH)2
This is a reaction.
The lime plaster is cured or dried.
Ca(OH)2 + CO2 → Ca(OH)(HCO3)
This is a reaction.
This quickly continues to react to form calcium carbonate and water.
Ca(OH)(HCO3) → CaCO3 + H2O
This is a reaction.
Frescos will deteriorate over time when exposed to the damp, acidic environments typical of modern urban city atmospheres.
CaCO3 + H2SO4 → CaSO4 + H2O + CO2
This is a reaction.
2. Balance each of the chemical equations you will be doing in this laboratory exercise.
Combustion:
C4H10 (g) + O2 (g) → CO2 (g) + H2O(g)
Synthesis:
Hb (s) + O2 → HbO2 (s)
Single Replacement:
Zn (s) + H3C6H5O7 (aq) → Zn3(H3C6H5O7)2 (aq) + H2 (g)
Double Replacement:
Zn(C2H3O2)2 (aq) + Na3PO4 (aq) → NaC2H3O2 (aq) + Zn3(PO4)2 (s)
Decomposition:
(NH4)2CO3 (s) → NH3 + H2O + CO2 (g)