Chem100 ANSWER KEY
Mid-Term Exam

1. From this list of pigments:

Vermilion—coccineal—red ochre—red lead—malachite—copper resinate—viridian, blue frit—ultramarine—smalt—blue verditer—cinnabar—indigo—verdigris
CHOOSE:
a) which pigments are synthetic? - Vermilion—red lead—copper resinate—viridian, blue frit—smalt—blue verditer—verdigris
b) three used by the Ancients? - any three from: red ochre—red lead—malachite—blue frit—cinnabar—indigo—verdigris
c) which are lakes as pigments? coccineal—indigo
d) which contain copper?—malachite—copper resinate—blue frit—blue verditer—verdigris
e) which are poisonous? Vermilion—red lead—cinnabar
f) which blue pigment contains no transition metal? ultramarine

2. What is the alchemical symbol for copper and its associated planet?
Venus

3. How are cinnabar and vermilion related? Both are HgS; vermilion is synthetic; cinnabar is natural mineral.

4. What are three types of chemical reactions covered thus far?
Any of the following:
Ion-exchange, acid-base, redox, precipitation.

5. A chemical reaction may incorporate several reaction types, as illustrated in the equation below:
Pb + 2 H3CCOOH + 1/2 O2 + Na2CO3 ‡ Pb (CO3) + H2O + 2 Na(H3CCOO)
- What type of reaction involves lead? - redox
- What type of reaction involves H3CCOOH? - acid/base
- What type of reaction involves the oxygen? - redox

6. What must the value of "x" be in each chemical formula below?
a) CsxS: x is 2
b) Mgx(OH)2: x is 1
c) HgxCO3: x is 1

7. a) Explain how an ancient Roman fresco might indeed contain the breath of Caligula.
Exhaled breath is essentially carbon dioxide, CO2. Carbon dioxide is a required molecule to combine with pit lime to cure fresco plaster to the final fresco according to:
Ca(OH)2 + CO2 = Ca(CO3)
Hence, frescos made in the ancient Rome Empire during the reign of Caligula may indeed have immrtalized him by binding his breath wastes into the art of fresco paintings.

b) Explain the main process that causes fresco deteroration.
The major process that causes fresco deterioration is soluble salt migration through porous fresco and then reprecipitation of salt crystals causing the fresco to crack.

c) Explain the relationship between limestone, marble and a fresco painting.
All are calcium carbonate. Limestone and marble are naturally formed CaCO3 minerals; the cured fresco is primarily calcium carbonate as well.

8. The symptoms associated with lead poisoning were called "plumbism" and "saturnism". Explain how these disease names relate to lead.
Plumbism refers to plumbum, the latin name for lead and the name which is the origin of lead chemical symbol, Pb.
Saturnism reflects that lead was the metal associated with the planet Saturn.

9. Use two examples to illustrate the main thesis of "Bright Earth".
Thesis: the ancestor disciplines to art and chemistry were once closely by the materials of art.
- creation of lake pigments from ancient dye industry
- symbolic use of vermilion/cinnabar is related to its importance in alchemy.
- New pigments were a goal of alchemy and modern chemistry
- As new minerals and/or pigments were discovered, the palettes used by painters changed.
- The ancestor companies of today's giant chemical and pharmaceutical companies began in color chemistry (dyes).
… and more!!!

10. Describe at least two evolutions in painting between the Medieval and the Renaissance and explain what contributed to these changes.
Some possible topics to enlarge upon:
- perspective
- move away from solely religious themes to landscapes and classical themes and others
- use of drying oils as binders