Gases – Chap. 10
BHSc – 2025
Lectured by: Dr. G. Ngubeni
,States of Matter
• Liquid/solids
substances under
ordinary conditions,
can also exist as
gases (vapours).
• Example: H2O
• Liquid water
• Ice
• Water Vapour
2
, Characteristics of Gases
• Unlike liquids and solids, gases…
➢Expand to fill their containers.
➢Are highly compressible.
➢Have extremely low densities.
➢Form homogeneous mixtures with other gases.
➢Only occupy about 0.1% of the volume of their
container.
3
, Examples
• Greenhouse Gases: CO2 and CH4
• Our Atmosphere – is made up of a mixture of gases
Nitrogen 78%
Oxygen 21%
Carbon Dioxide
0.03%
Other 0.01%
• Other elements/gases at standard Temp. and Pres.:
• H2; F2; Cl2
• More examples on Table 10.1.
4
BHSc – 2025
Lectured by: Dr. G. Ngubeni
,States of Matter
• Liquid/solids
substances under
ordinary conditions,
can also exist as
gases (vapours).
• Example: H2O
• Liquid water
• Ice
• Water Vapour
2
, Characteristics of Gases
• Unlike liquids and solids, gases…
➢Expand to fill their containers.
➢Are highly compressible.
➢Have extremely low densities.
➢Form homogeneous mixtures with other gases.
➢Only occupy about 0.1% of the volume of their
container.
3
, Examples
• Greenhouse Gases: CO2 and CH4
• Our Atmosphere – is made up of a mixture of gases
Nitrogen 78%
Oxygen 21%
Carbon Dioxide
0.03%
Other 0.01%
• Other elements/gases at standard Temp. and Pres.:
• H2; F2; Cl2
• More examples on Table 10.1.
4
