Gases and the Kinetic Theory Flashcards
What is pressure?
The force exerted per unit area
How can you measure pressure?
Pressure gauge
What is the cause of pressure of a gas?
The force the gas particles exert on the walls of its container (or on objects inside the gas)
What 3 things can affect the motion of particles?
- Pressure
- Volume (of container)
- Temperature
What happens to volume as pressure increases?
Volume decreases
What happens to pressure as temperature increases?
Pressure increases
What happens to volume as temperature increases?
Volume increases
What is Boyle’s Law?
Temperature is constant
As volume increases, pressure decreases
Pressure x Volume = constant
P1 x V1 = P2 x V2
What is the Pressure Law?
Given mass and constant volume of an ideal gas, pressure exerted on sides of container is directly proportional to its absolute temperature
P divide by T = constant
What is Charles’ Law?
Given mass of an ideal gas at constant pressure, volume is directly proportional to its absolute temperature assuming a closed system
V divide by T = constant
If gas laws are combined (Ideal Gas Equation)
P1 x V1 divide by T1 = P2 x V2 divide by T2
Which is the least energetic and which is the most?
Solid, liquid, gas
- Solid is the least energetic
- Gas is the most energetic
Description of Solid
- Holds shape
- Fixed volume
Description of Liquid
- Shape of container
- Fixed volume
- Free surface
Description of Gas
- Shape of container
- Volume of container
Kinetic Theory
Idea that a gas is made from tiny particles that are constantly, randomly moving. All collisions are elastic (no KE lost)
How is pressure created in gases?
Gas particles colliding with inside surface of container
As volume decreases, pressure increases. This means that…
Pressure is inversely proportional to volume
When temperature (Kelvin) is doubled, pressure doubles. This means that…
Pressure is directly proportional to temperature
When temperature (Kelvin) is doubled, volume doubles. This means that…
Volume is directly proportional to temperature
Explain how volume of gas decreases as pressure increases using kinetic theory (QWC)
As volume decreases, the same number of gas particles are moving around in smaller space and so are closer together. Average speed of particles remains the same at constant temperature. But, there are more particles hitting inside of container each second. When particles strike wall of container there’s a change in momentum of particles (Newton’s 2nd law) which results in a force on particles creating an equal but opposite force on walls (Newton’s 3rd law). More force acting on inside surface. Since P = F/A , pressure increases
Why is conduction slow in gases?
Atoms are further apart so collide less often
What happens during convection?
Liquids/gases heated up which leads to their atoms/molecules colliding at higher speeds more often
