Gold is a yellowish metal with a density of 19.33 g/cm3. It has a melting point of 1064°C and a boiling point of 2807°C. Gold does not react with water but does react with acids. It is an excellent conductor of heat and electricity. Pyrite, also known as fool's gold, resembles gold but has a lower density of 4.84 g/cm3. Unlike gold, pyrite reacts with oxygen and water in air to form sulfate and cause acidic mine drainage.

1. Tarnished silver…

2. Substance
Melting Point
(°C)
Boiling Point
(°C)
State at room
temp.*
Water 0 100
Chloroform -64 61
Ethanol -117 79
Propane -190 -42
Table salt 801 1,465
*Note: Room temperature is about 20°C

3. Pyrite (FeS2)is a mineral that is commonly known as “fool’s
gold” due to its resemblance to gold (Au). Pyrite exposed to
the atmosphere during mining slowly reacts with oxygen and
water to form sulfate, resulting in acidic mine drainage. Gold
does not react with water or air. Gold has a density of 19.33
g/cm3 and pyrite has a density of 4.84 g/cm3.
Identify the physical and chemical properties of each
substance.

4. Gold (Au) is a yellowish metal that is an excellent conductor of
heat and electricity. The density of gold is 19.33 g/cm3. The
melting point is 1064°C and the boiling point is 2807°C. Gold
does not react with water but it does react with acid.
Physical Properties Chemical Properties

5. Fe2O3
1. How many elements are shown in the formula?
2. How many atoms are shown in the formula?
3. Is this an element, compound, or mixture?
4. Is this a pure substance?

6. Which formulas represent compounds?
Which formulas represent elements?
a) N2, H2O2
b) CO2, H2O
c) H2, C6H12O6
d) H2, N2

7. What unit of density would be appropriate to describe a solid
bar of silver?
a. g/mL
b. g/cm3
c. oz/ft3
d. kg/L

8. Compare and contrast mixtures and compounds. Which
statement is true about mixtures and compounds?
a) Both mixtures and compounds are the same
throughout.
b) Mixtures and compounds are made of two or more
elements in a definite proportion.
c) Mixtures must be separated by chemical methods and
compounds by physical methods.
d) Mixtures contain two or more elements physically
combined and compounds contain two or more
elements chemically combined.

9. Which of the following sentences best describes table salt
(NaCl)?
a) Salt is a compound made from two elements.
b) Salt is a mixture made from two elements.
c) Salt is an element made from two mixtures.
d) Salt pure substance made from two compounds.

10. If different colored dots represent different atoms, what type of
substance is pictured below?
a. mixture
b. compound
c. element
d. solution

11. If different colored dots represent different atoms, what type of
substance is pictured below?
a. mixture
b. compound
c. element
d. pure substance

12. If different colored dots represent different atoms, what type of
substance is pictured below?
a. mixture
b. compound
c. element
d. pure substance

13. After swimming in the ocean, Mark sits in the sun to dry off. He
notices small white crystals on his skin. Which is the most
reasonable explanation for what has happened to Mark?
a) The water evaporated and attracted dust to Mark’s skin.
b) The white crystals are dead skin cells that are being shed.
c) Mark has developed a rash.
d) Salt that was dissolved in the ocean water remained on
Mark’s skin after the water evaporated.

14. Which statement about the molecules in ice and the molecules
in liquid water is correct?
a) The molecules in ice have more energy than the
molecules in liquid water.
b) The molecules in ice contain different atoms than the
molecules in liquid water.
c) The molecules in ice have more electric charge than the
molecules in liquid water.
d) The molecules in ice are less free to move than the
molecules in liquid water.

15. What do the following elements have in common?
a) Helium(He), neon (Ne), argon (Ar), krypton (Kr)
b) Lithium (Li), sodium (Na), potassium (K)

16. How small can you cut up a piece of gold (Au) and it still have all
the same characteristic properties as gold?
a) Proton
b) Neutron
c) Electron
d) Nucleus
e) Atom
f) Molecule

17. a) Soduim (Na) is a(n) _________________.
b) Chlorine (Cl) is a(n) _________________.
c) Salt (NaCl) is a(n) ________________.
d) Hydrogen is a(n) ________________.
e) Oxygen is a(n) ________________.
f) Water (H2O) is a(n) ________________.
g) Salt water (NaCl + H2O) is a(n) ________________.
Element Compound Mixture
Pure substance (Y/N)

18. Characteristic properties describe the specific characteristics of
substances. What makes characteristic properties useful to
scientists?
a. They can be either physical or chemical.
b. They can be used to identify matter.
c. They are easy to observe and measure.
d. Sample size does not matter.

19. How does a physical change differ from a chemical change?
a. In a physical change new volumes are created.
b. In a physical change new materials are produced.
c. In a physical change the composition is unchanged.
d. In a physical change the change is reversible.

20. What happens to matter during chemical changes?
a. It retains its identity.
b. Its composition changes.
c. The state of matter changes.
d. Only the form of the matter changes.