def

gas

Substance with neither definite volume nor shape

meta

supertypes

marker

Marker labels a dict with typing information

    phenomenon

Aspect of scientific interest with measurable quantities

        substance

Matter in one the three states solid, liquid, or gas

            fluid

Liquid or gas

subtypes

air

The mixture of gases which surrounds the earth

ch2o

Formaldehyde (CH₂O)

ch4

Methane (CH₄)

co

Carbon monoxide (CO)

co2

Carbon dioxide (CO₂)

hfc

Hydrofluorocarbons

n2o

Nitrous oxide (N₂O)

naturalGas

Fossil fuel energy source consisting largely of methane and other hydrocarbons

nf3

Nitrogen trifluoride (NF₃)

nh3

Ammonia (NH₃)

no2

Nitrogen dioxide (NO₂)

o2

Oxygen (O₂) - the common dioxygen allotrope in the air

o3

Ozone (O₃)

pfc

Perfluorocarbons

propane

By-product of natural gas processing and petroleum refining (C₃H₈)

sf6

Sulphur hexafluoride (SF₆)

steam

Water in its gas form

tvoc

Total volatile organic compound (TVOC)

quantities

concentration

Abundance of substance in the total volume of a mixture

flow

Measure of volumetric flow of fluid

level

Range from 0% to 100%

pressure

Measure of force applied

temp

Temperature - measure of hot and cold

volume

Three dimensional space occupied by a substance