The document discusses several measurable properties of gases, including volume, pressure, and temperature. It defines volume as the space a gas occupies in its container. Pressure is defined as the force exerted by gas molecules divided by the surface area. Common pressure units are provided. Temperature is defined as the average kinetic energy of gas particles. Standard temperature and pressure conditions for gases are outlined, with standard temperature being 0°C and standard pressure being 1 atmosphere. Boyle's law relating the inverse relationship between gas pressure and volume at constant temperature is briefly explained.

1. BEHAVIOR OF GASES

2. Measurable Properties of Gas
 Volume
The volume of a gas is equal to the volume of its container.
This is because the gas occupies all spaces available in its vessel.
The common units of volume used in gas measurements are:
 liter (L),
 milliliter (mL),
 cubic meter (m3) and
 cubic centimeter (cm3).
 Pressure
The pressure of a gas is the force exerted by the gas molecules
on the walls of its container divided by the surface area of the
container. The Earth’s atmosphere exerts pressure on us at 1.013
x105 N/m2 or 1 atm (atmosphere).

3. Pressure
area
force
pressure 
Which shoes create the most pressure?

4. Atmospheric Pressure
 The gas molecules in the atmosphere are pulled
toward Earth due to gravity, exerting pressure
 Why do your ears ‘pop’ in an airplane?

5. Pressure
 Barometer
 measures atmospheric
pressure
Mercury Barometer

6. Units of Pressure
2
m
N
kPa 
 At Standard Atmospheric Pressure (SAP)
101.325 kPa (kilopascal)
1 atm (atmosphere)
760 mm Hg
(millimeter Hg)
760 torr
14.7 psi (pounds per square inch)

7. Atmospheric pressure decreases as altitude increases.
The common units of pressure and their equivalent are as follow:
1 atm = 1.013 x105 N/m2 = 1.013 x105 Pa
1 atm = 760 torr = 760 mmHg
1 atm = 14.696 psi
Temperature
The temperature of a gas is the average kinetic energy of the
particles of gas.
It is usually determined using a thermometer.
It is usually expressed in degree Celsius (°C), degree Fahrenheit
(°F) and Kelvin (K). However, only Kelvin is used in computations
involving temperature of gas:
°C = (°F -32) / 1.8 °F = 1.8°C + 32 K = °C + 273

8. Standard Conditions of a Gas
The standard condition for a gas is also known as STP or the
Standard Temperature and Pressure
The standard temperature is the melting of an ice which is
0°C or 273K.
The standard pressure is the average pressure of the
atmosphere at sea level which is equal to 1 atm.
One mole of gas occupies a volume of 22.4 L.

9. Boyle’s law, also called Mariotte’s law, a
relation concerning the compression and
expansion of a gas at constant temperature.
This empirical relation, formulated by the
physicist Robert Boyle in 1662,
states that the pressure (p) of a given
quantity of gas varies inversely with its
volume (v) at constant temperature
in equation form, pv = k, a constant. The
relationship was also discovered by the French
physicist Edme Mariotte