Ideal Gases Flashcards
One mole definition
the amount of substance that contains as mamy elementary entities as there are atoms in 0.012kg of carbon-12
what does 1 mol of any substance contain
6.02 * 10^23 individual atoms or molecules
total number of atoms in a substance equation
N (total no. of molecules) = n (number of moles) x avagadro’s constant
How do atoms in an ideal gas cause pressure?
The atoms or molecules in a gas are always moving and when they collide with the walls of the container , the container exerts a force on them (Newton’s 3rd Law), changing their momentum as they bounce off the wall.
What happens to the velocity of the atom when it bounces off the container?
It becomes negative since velocity is a vector
pressure and volume relationship
if the temperature and mass of gas remain constant then the pressure of an ideal gas is inversely proportional to its volume.
what is boyle’s law
pressure exerted by a gas at constant temperature varies inversely with the volume of the gas.
Pressure and temperature relationship
if the volume and mass of a gas remains constant, the pressure of an ideal gas is driectly proportional to its absolute (thermodynamic) temperature in kelvins
what is the combined gas law
P1V1/T1 = P2V2/T2
what is the combined gas law constant, nR
pV/t
what is the value for the molar gas constant
8.31 JK -1 mol -1
what is the equation of state of an ideal gas
pV/T = nR OR pV = nRT
how is the Boltzmann constant calculated
the molar gas constant/ avagadro’s constant
what is the boltzmann constant
1.38 x 10^-23
equation of state of an ideal gas with the boltzmann constant
pV = N(number of particles in gas sample)k(avagadro’s constant)T
what affects particles having different speeds
particles have different masses so their r.m.s. speeds will be different
what is the internal energy of a gas
the sum of the kinetic and potential energies
what is the nature of internal energy in an ideal gas
one of the assumptions of an ideal gas is that the electrostatic forces between particles is negligible except during collisions, so there is no electric potential energy in an ideal gas. all the internal energy is in the form of the KE of particles.
Why does higher temperature lead to higher pressure
The hotter the gas, the faster the molecules move
Hence the molecules collide with the surface of the walls more frequently
Since force is the rate of change of momentum:
Each collision applies a force across the surface area of the walls
The faster the molecules hit the walls, the greater the force on them
Since pressure is the force per unit area
Higher temperature leads to higher pressure
pressure in an ideal gas
The frequency of collisions of the gas molecules per unit area of a container
what does isothermic mean
if a change in a gas is isothermic it means temperature is constant
what does isobaric mean
when change has no change in pressure
