Tarnished silver…

SubstanceMelting 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

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.

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

Fe2O31. 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?

Which formulas represent compounds?Which formulas represent elements?

a) N2, H2O2

b) CO2, H2Oc) H2, C6H12O6

d) H2, N2

What unit of density would be appropriate to describe a solid bar of silver?

a. g/mLb. g/cm3

c. oz/ft3

d. kg/L

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.

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.

If different colored dots represent different atoms, what type of substance is pictured below?

a. mixtureb. compound c. element d. solution

If different colored dots represent different atoms, what type of substance is pictured below?

a. mixtureb. compound c. element d. pure substance

If different colored dots represent different atoms, what type of substance is pictured below?

a. mixtureb. compound c. element d. pure substance

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.

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.

What do the following elements have in common?

a) Helium(He), neon (Ne), argon (Ar), krypton (Kr)b) Lithium (Li), sodium (Na), potassium (K)

How small can you cut up a piece of gold (Au) and it still have all the same characteristic properties as gold?

a) Protonb) Neutronc) Electrond) Nucleuse) Atomf) Molecule

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 MixturePure substance (Y/N)

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.

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.

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.