Examine the figure on page 13 and answer the following questions.
A.) What is distillation?
B.) Why is the process in this figure called fractional distillation?
C.) Why must crude oil go through this process in order to be useful?
D.) Describe the relationship between molecular mass, density, and boiling point for hydrocarbons.
E.) Use molecule structure to explain the relationship between molecular mass and boiling point.

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).

answer seismograph;

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.