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The simplest hydrocarbon is methane (CH 4). It has one atom of
carbon(C) and four atoms of hydrogen (H). Under normal pressure
and normal temperature, methane is a gas. Normal pressure is the
pressure the atmosphere exerts at sea level. Normal temperature
ranges from about 60 to 68 degrees Fahrenheit, or 15 to 10 degrees
Celsius. Methane is the main component of natural gas. Natural gas
occurs in buried rock layers usually mixed with other hydrocarbon
gases and liquids. Sometimes it also contains nonhydrocarbon gases
and liquids such as helium, carbon dioxide, nitrogen, and water. After
natural gas is produced, a gas-processing facility removes such
impurities before the gas reaches consumers.
LIQUEFIED PETROLEUM GAS (LPG)

Ethane, propane, and butane often occur with natural gas. They
are, however, heavier than methane so gas-processing equipment
removes them from methane before the methane goes to consumers.
Liquefied petroleum gas (LPG, or hydrogas) is mainly propane (C 3H 8)
and butane (C 4H 10); it may also contain ethane (C 2H 6).
When you compress propane and butane a little at normal
temperature – that is, when you raise the pressure on them slightly
above atmospheric pressure at normal temperature – they liquefy.
When you release the pressure, they turn into gas. Thus, you can use
LPG as a portable fuel. It travels in a pressurized container as a liquid.
When you connect the container to a stove's burner, for example, LPG
changes into gas when you turn on the burner and release the pressure.
CRUDE OIL
Crude oil is a hydrocarbon mixture that often occurs as a liquid,
though some crude oils are very thick and dense and do not flow
easily. Crude oil varies considerably in weight, viscosity, and color. It
may also contain nonhydrocarbon impurities such as hydrogen sulfide.
Generally, oil companies classify crude oil as light, intermediate, or
heavy and, if it contains hydrogen sulfide, they call it “sour

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