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COLLEGE CHEMISTRY – GAS PRESSURE NOTES AND PRESSURE CONVERSIONS
You will need to memorize the following information about gas pressure for the chapter
exam..
1.
What are the four properties of gases whose relationships are most easily observed?
pressure, temperature, volume and mass
2.
Explain how the pressure changes inside of a soccer ball when you add air to it.
Pumping air inside a ball increases the number of molecules in the ball,
meaning a greater pressure on inner wall since there are more collisions. The
ball then becomes firmer.
3.
Define “pressure of a gas”.
Force per unit area the particles in a gas exert on the walls of their container.
4.
The pressure of a gas is ____directly_____ proportional to its mass.
5.
The pressure of a gas is ____directly_____ proportional to the number of particles.
6.
If the volume of a container and the number of particles of a gas are not changed,
the pressure of a gas __increases in direct proportion__ to the Kelvin temperature.
7.
The volume of a gas at constant pressure is ___directly related____ to the Kelvin
temperature.
8.
Define barometer.
Instrument that measures the pressure exerted by the atmosphere.
9.
Describe how Torricelli’s barometer works.
A tube of mercury stands in a dish of mercury. The atmosphere exerts a
pressure on the dish, thus moving the mercury in the tube up and down.
10.
Are there higher pressures at lower altitudes or higher altitudes? What is the reason
for this?
Lower altitudes because there is more air above to exert pressure.
11.
One standard atmosphere (atm) is defined as what?
The pressure that supports a 760 mm tube of mercury.
The following are all equivalent pressures:
1.00 atm (atmospheres)
760 mm Hg (millimeters of Mercury)
29.9 in Hg (inches of Mercury)
14.7 psi (pounds per square inch)
101.3 kPa (kilopascals)
Use dimensional analysis, and the equivalent pressures above, to convert the following
pressures.
ex:
35 psi to kPa
35 psi
x
101.3 kPa
14.7 psi
12.
59.8 in Hg to psi
13.
7.35 psi to mm Hg
14.
1140 mm Hg to kPa
15.
19.0 psi to kPa
16.
1.45 atm to in Hg
17.
195 kPa to atm
18.
3.36 psi to mm Hg
19.
922 mm Hg to psi
20.
38.5 in Hg to atm
=
240 kPa