IDEAL GASES Flashcards
Reiterate the SI base units
Kg, m, s, A, mol, K, cd
one mole is defined as
the amount of substance that contains as many elementary entities as there are atoms in 12g of carbon-12.
What is the Avogadro constant ?
6.02 x 10^23, the number of atoms in 12g of carbon-12.
the total no of atoms or molecules in a substance, N, is
N = n x Nₐ, where Nₐ is the Avogadro constant and n is the number of moles in a substance
How to calculate the molar mass ?
M = m / n, where m is the total mass of the substance and M is the molar mass aka the mass of one mole
What is the kinetic theory of matter?
is a model used to describe the behavior of the atoms or molecules in an ideal gas, as real gases have complex behaviors, hence a number of assumptions are made.
what are the assumptions that the the kinetic theory of matter uses?
- the gas contains a very large no of atoms or molecules moving in random directions with random speeds
- the atoms or molecules of the gas occupy a negligible volume compared to the volume of the container
- the collisions of atoms or molecules with each other and the container are completely elastic
- the time of collisions between the particles is negligible compared to the time between collisions
- electrostatic forces between atoms or molecules are negligible except during collisions
Using the newton’s law’s assumptions and the assumptions from the kinetic theory of matter
we can describe how molecules or atoms cause pressure in an ideal gas
the total change in momentum for a colliding particle against the walls of the container is…
-2mu
pV=
nRt
pV=
pV=1/3 x N x ¬(c^2)¬
pV=
pV=nkNat
derive
Whats the name of the distribution that shows different particles speed at different temperatures
Maxwell Boltzmann Distribution
What’s the name of the distribution that shows different particles speed at different temperatures
Maxwell Boltzmann Distribution
What effect does increasing the temperature of the gas has on the Maxwell Boltzmann distribution?
The hotter the temperature, the greater the range of speeds. The most modal speed and r.m.s. increases and the distribution becomes more spread out
The Boltzmann constant
k=R/Na=1.38 x 10^-23
pV=
pV=Nkt
What those Boyle’s Law states?
Boyle’s Law states that for a fixed mass of an ideal gas at a constant temperature, its pressure is inversely proportional to its volume
Why do we have to increase the pressure of the gas slowly when conducting an experiment to explore the validation of Boyle’s Law?
Because increasing the pressure too quickly will lead to a change in temperature, meaning that Boyle’s Law cannot be verified using these affected values
what does the left hand side of this equation represents?
1/2(m(¬c¬)^2)=3/2(kT)
The average kinetic energy of each particle in the gas
Brownian motion is caused by.
collisions between air particles and smoke particles
A mixture of argon atoms and helium atoms in a cylinder enclosed with a piston. The mixture is at a temperature of 310K. Compare the kinetic energy of the argon atoms and helium atoms in the mixture.
Both gases have the same mean or average kinetic energy
Explain, in terms of the kinetic theory model, why a pressure is exerted by the gas on the piston.
The particles constantly collide with the walls of the piston and change momentum upon collision, exerting a force or impulse that it is equal to the rate of change in momentum.
Use the ideas from kinetic theory to explain why gas molecules have a range of speeds but are unlikely to have speeds much greater than the most common speed.
Particles collide with each other, exchanging energies. For a particle to have a much greater speed than the common speed, they will have to gain a lot of energy by colliding successively and frequently, which is unlikely.
Explain what is meant by an ideal gas
In an ideal gas particles have negligible volume compared to that of the container. Also, all collisions with the container other particles are perfectly elastic and there are no interactions between particles except during collisions.
