Chemistry Lecture – Air Composition, Methane & Concentration Units

17 fill-in-the-blank flashcards covering the chemistry triplet, air composition, greenhouse gases, methane sources, ppm/percent definitions, and unit conversions.

The three inter-connected views chemists use (macroscopic, submicroscopic, symbolic) are collectively called the __.

chemistry triplet

Observations that can be made with the naked eye occur on the __ level.

macroscopic

The particle-level picture of atoms and molecules is referred to as the __ level.

submicroscopic (particle) level

Chemical symbols and formulas such as H₂O belong to the __ level of representation.

symbolic

Air is classified as a __ rather than a compound.

mixture

Approximately _ % of dry air is nitrogen.

78

Approximately __ % of dry air is oxygen.

21

Nitrogen and oxygen together make up about __ % of the atmosphere.

99

Besides argon and carbon dioxide, the important trace greenhouse gas in air is __.

methane

Methane and carbon dioxide are called __ gases because they trap heat in the atmosphere.

greenhouse

The number-one source of methane emissions in the United States is __.

cow (cattle) farming / livestock digestion

Feeding cattle a special red __ can cut their methane production by about 80 %.

seaweed

The abbreviation ppm stands for __.

parts per million

One part in 1,000,000 parts corresponds to __ ppm.

1

To convert a percentage to ppm, multiply by __.

10,000

1.7 ppm of methane expressed as a percentage is __ %.

0.00017

0.00007 % methane expressed in ppm is __ ppm.

0.7