Thermal Flashcards
(13 cards)
What is a mole?
The amount of a substance which contains the same number of particles as there are atoms of 12g of carbon 12
What is ideal gas equation and one function?
PV=nRT or PV=NkT, for an ideal gas the forces between particles are assumed to be zero except during a collision. the potential energy of the gas is assumed to be zero.
What is Boyles law?
Pressure is inversely proportional to volume
What is the pressure temperature law?
Pressure is directly proportional to temperature when volume is kept constant
What temperature is absolute zero
-273C
What is the difference between n and N
n: Number of moles (mol) , N: Number of molecules
Define molar mass
The mass of one mole of a substance, expressed in grams per mole (g/mol).
State four assumptions of the ideal gas model
1)Gas molecules move in random, constant motion.
2)Collisions between molecules and with container walls are elastic.
3)The volume of the gas molecules is negligible compared to the container volume.
4)There are no intermolecular forces between gas molecules/ No forces act between particles except during collisions
How does kinetic theory explain Boyleβs law (ππ=constant)?
1)Reducing volume increases collision frequency.
2)More collisions per unit area mean higher pressure
3)P inversely proportional to V at constant temperature.
Define root-mean-square speed (π rms)
The root-mean-square speed is the square root of the mean of the squares of the speeds of all molecules in a gas
How does kinetic theory explain the pressure law (π/π=constant)?
1)Higher temperature increases molecule speeds
2)Faster molecules lead to more forceful collisions
3)Pressure increases proportionally with temperature in Kelvin
Why does pressure increase when temperature increases?
1)pressure is force divided by area and force is rate of change in momentum
2)mean speed of air molecules is going to increase
3)more collisions with container wall (greater change of momentum for each collision)
How do you work out work done for a gas?
Work done equals pressure times change in volume (W=PV)
