1. What are the three components of the scientific method? Is it necessary for an individual to conduct experiments to follow the scientific method?
2. Identify each statement as a theory or a law and explain your reasoning.
a. The ratio of elements in a pure substance is constant.
b. An object appears black because it absorbs all the visible light that strikes it.
c. Energy is neither created nor destroyed.
d. Metals conduct electricity because their electrons are not tightly bound to a particular nucleus and are therefore free to migrate.
3. Identify each statement as a theory or a law and explain your reasoning.
a. A pure chemical substance contains the same proportion of elements by mass.
b. The universe is expanding.
c. Oppositely charged particles attract each other.
d. Life exists on other planets.
4. Classify each statement as a qualitative observation or a quantitative observation.
a. Mercury and bromine are the only elements that are liquids at room temperature.
b. An element is both malleable and ductile.
c. The density of iron is 7.87 g/cm3.
d. Lead absorbs sound very effectively.
e. A meteorite contains 20% nickel by mass.
5. Classify each statement as a quantitative observation or a qualitative observation.
a. Nickel deficiency in rats is associated with retarded growth.
b. Boron is a good conductor of electricity at high temperatures.
c. There are 1.4–2.3 g of zinc in an average 70 kg adult.
d. Certain osmium compounds found in air in concentrations as low as 10.7 µg/m3 can cause lung cancer.