Why is the normal boiling point of a liquid the point at which the vapor pressure is equal to atmospheric pressure, #"760 torr"#?
1 Answer
The boiling point of water is established relative to standard atmospheric pressure of 101.325 kilopascals which is the pressure experienced by a square meter of atmosphere pressing down on the surface of the earth.
Explanation:
Boiling point is established relative to the standard atmosphere. The standard atmosphere is based upon the weight of a column of earth's atmosphere at the surface (average sea level) with specific dimensions.
In general, pressure is defined as force per unit area.
#P = F/A#
That is, given a column of earth's atmosphere having the dimensions of one square meter at earth's surface and an altitude up to the top of the mesosphere would exert an average force/area of
#"101.325 kPa"# #=# #"760 torr"# .
At this atmospheric pressure, the boiling point of water is
