Gases, Liquids and Solids Flashcards
When all the molecules
of a system become motionless and line up perfectly, we achieve
the greatest possible order.
entropy
Kinetic energy increases with
increasing temperature.
true
At high temperatures, molecules possess a high kinetic energy and move
so fast that the attractive forces between them are too weak to hold them
together. This situation is called the
gaseous state
At lower temperatures,
molecules move more slowly, to the point where the forces of attraction
between them become important. When the temperature is low enough, a gas
condenses to form a
liquid state
When the temperature is even lower, molecules no longer have enough
velocity to move past each other.
solid state
each molecule has a certain number of nearest neighbors, and these neighbors do not change
solid state
Typically a solid,
when heated to a sufficiently high temperature, melts and becomes a liquid.
The temperature at which this change takes place is called the
melting point
Further heating causes the temperature to rise to the point at which
the liquid boils and becomes a gas. This temperature is called the
boiling point
The force per unit area
exerted against a surface
pressure
Instrument used to measure atmospheric pressure
barometer
Pressure is most commonly measured in
mmHg
Pressure is also measure in torr, a unit named in honor of
Evangelista Torricelli
At sea level, the average pressure of the
atmosphere is
760 mmHg
A barometer is adequate for measuring the pressure of the atmosphere,
but to measure the pressure of a gas in a container, we use a simpler instrument called a
manometer
states that for a fixed mass of gas at a constant temperature, the
volume of the gas is inversely proportional to the pressure.
Boyle’s Law
P1V1 = P2V2
Boyle’s Law
states that the volume of a fixed mass of gas at a constant
pressure is directly proportional to the temperature in kelvins (K).
Charles’ Law
(V1/T1) = (V2/T2)
Charles’ Law
states that, for a fixed mass of a gas at constant volume,
the pressure is directly proportional to the temperature in kelvins (K)
Gay-Lussac’s Law
(P1/T1) = (P2/T2)
Gay-Lussac’s Law
The three gas laws can be combined and expressed by a mathematical
equation called the
Combined gas law
(P1V1/T1) = (P2V2/T2)
Combined gas law
Equal volumes
of gases at the same temperature
and pressure contain the same
number of molecules
Avogadro’s Law
Standard pressure
1atm