Gases
, Gases
• have large spaces between the gas molecules → not
tightly packed
• expand to fill the container → take the shape of the
container
• diffuse into one another and mix
• 4 properties that affect its physical behaviour:
✓ amount of gas (in moles)
✓ Volume
✓ Temperature & pressure
, Pressure
What is pressure?
❑ it is the force per unit area ––(force divided by the area
over which the force is applied)
❑ The unit is N.m-2 which is one pascal (Pa)
𝐅 (𝐍)
𝐏 𝐩𝐚 =
𝐀 (𝐦𝟐 )
, Barometric Pressure
• The simplest device used to measure pressure is the
Toricelli barometer
• Standard atmosphere (atm) is the pressure exerted by
a mercury column of 760 mm (density of Hg = 13.5951
g.cm-3 (0 0C and gravity = 9.80665 m.s-2)
, Gases
• have large spaces between the gas molecules → not
tightly packed
• expand to fill the container → take the shape of the
container
• diffuse into one another and mix
• 4 properties that affect its physical behaviour:
✓ amount of gas (in moles)
✓ Volume
✓ Temperature & pressure
, Pressure
What is pressure?
❑ it is the force per unit area ––(force divided by the area
over which the force is applied)
❑ The unit is N.m-2 which is one pascal (Pa)
𝐅 (𝐍)
𝐏 𝐩𝐚 =
𝐀 (𝐦𝟐 )
, Barometric Pressure
• The simplest device used to measure pressure is the
Toricelli barometer
• Standard atmosphere (atm) is the pressure exerted by
a mercury column of 760 mm (density of Hg = 13.5951
g.cm-3 (0 0C and gravity = 9.80665 m.s-2)
