Module 3- Chemistry

Question 1

What is a gas?

Answer 1

Any substance that boils at atmospheric pressure at any temperature less than 80 degrees F. DOT defines gases as materials with a boiling point below 68 degrees F.

Question 2

Compressed Gas

Answer 2

Material when in a container has an absolute pressure of 40psi @ 70F or having an absolute pressure exceeding 104 psi at 130F or
any liquid having a vapor pressure exceeding 40 psi at 100F

Question 3

Liquefied Compressed Gas

Answer 3

Gases that become a liquid in a container at
normal temperature at pressure from 25 to 2,500 psi.

Question 4

Cryogenic Gas

Answer 4

Liquefied gases with boiling points below -130 F

Question 5

Liquid

Answer 5

Liquids have a fixed volume but no fixed shape and will take on the shape of their container.

Question 6

What will liquids do at any temperature above their freezing point?

Answer 6

Release vapors.

Question 7

Solids

Answer 7

Immobile material with a fixed volume and shape. Can be broken down into dust or powder and transmitted via different modes.

Question 8

Pure Substances

Answer 8

Homogeneous material having a constant, fixed chemical
composition with no impurities. They may be an element or a compound.

Example: oxygen, chlorine, carbon monoxide, water

Question 9

Element

Answer 9

Simplest form of any substance cannot be decomposed into smaller units and remain that element. The smallest unit of an element is an atom.

Example: hydrogen, carbon, oxygen, iron, fluorine

Question 10

Compounds

Answer 10

A substance composed of two or more elements in chemical
combination that has a fixed chemical composition.

Example: methane (CH4), sodium chloride (NaCl), carbon dioxide (CO2)

Question 11

Mixture

Answer 11

Materials that are made from two or more substances in varying
proportions that are NOT chemically combined. These materials can be separated from each other by physical or chemical means (filtering, dissolving, evaporating, etc.)

Example: air, gasoline, brass, wood