3/19/07-2/23/07
Monday, 3/19/07
Packet pg 457: 8 a, b, c, d; 18 a, b, c, d
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Summary
Postulates of the Kinetic Molecular theory of Gases
- Gases consist of tiny particles (atoms or molecules)
- These particles are so small, compared to the distances between them, that the volume (size) of the individual particles can be assumed to be negligible (zero)
- The particles are in constant random motion, colliding with the walls of the container. These collisions with the walls cause the pressure exerted by the gas.
- The particles are assumed not tot attract or to repel each other.
- The averages kinetic energy of the gas particles is directly proportional or the Kelvin temperature of the gas.
The meaning of
temperature
Temperature really is a measure of the motions of the gas particles
The relationship
between pressure and temperature
As the gas is heated to a higher temperature, the particles move fast, hitting the walls more often. If the pressure is due to collisions with the walls, the gas pressure should increase as the temperature is increases.
The relationship
between volume and temperature
What happens we heat the as to a higher temperature. As the Temperature increases, the particles move faster, causing the gas pressure to increase. Therefore, the Kinetic Molecular model predicts that the volume of the gas will increase as we raise its temperature at constant pressure.
Units of pressure
1 standard atmosphere = 1.000 atom = 760.0 mm Hg = 760.0 torr.
The SI unit for pressure is pascal (Pa)
1 standard atmosphere = 101,325 Pa
1.0 atom = 14.69 lbs/in2
- Atmospheric pressure is measured with a barometer. The most commonly used units of pressure are mm Hg (torr), atmospheres, and pascals (the SI units).
- Boyle’s law states that the volume of a given amount of gas is inversely proportional to its pressure (at constant temperature): PV = k or P = k/V. That is, as pressure increases, volume decreases.
- Charles’s law states that, for a given amount of gas at constant pressure, the volume is directly proportional to the temperature (in kelvins): V = bT. At -273 C (O K), the volume of a gas extrapolates to zero, and this temperature is called absolute zero.
- Avogadro’s law states that for a gas at constant temperature and pressure, the volume is directly proportional to the number of moles and gas: V = an.
5. The kinetic molecular theory of gases is a model that accounts for ideal gas behavior. This model assumes that a gas consists of tiny particles with negligible volumes, that there are no interactions among particles, and that the particles are in constant motion, colliding with the container walls to produce pressure.
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Wednesday 3/21/07
TEST
Thursday 3/22/07
pg 489 prob: 1, 2, 3
pg 492 prob: 1, 2, 8
Friday 2/23/07
pg 489 prob: 4, 5, 6
pg 493 prob: 25, 26, 27
