8A.3 Internal Energy Flashcards
what is the potential energy of particles
the energy a particle has relative to its position within the structure material, or in relation to other molecules in a substance
the potential energy of the particles is due to
the bonding between molecules
what is the internal energy
the sum of the kinetic and potential energies of all the molecules within a given mass of a substance
molecules dont have the same amount of
potential and kinetic energy
what is the maxwell-Boltzmann Distribution
a mathematical function that describes the distribution of energies amongst particles at a given temp
what are the characteristics of a m-b graph
- there are no molecules with zero energy
- only a few molecules have high energy
- there is no maximum value for energy a molecule can have
in molecules of the same object, their speed and their kinetic energy depend on
their speed varies(high speed, close to average, slow), and since all their masses are the same the Ek depends on speed
M-b axis are
y - the number of molecules
x - the energy (Ek) of molecules
A M-B graph is for one specific
temp
if we increase the temp what happens to the peak in the M-B graph
the peak becomes smaller and shifts to the right and therefore higher energies
what are the two ways to find the speed of molecules
- the peak of the M-B graph represents the kinetic energy value with the greatest number of molecules that have that energy, so the speed corresponding to that Ek is the average speed
- using root-mean-square-calculation with v = root(<c^2>)
what is the rms speed
the square root of the arithmetic mean value of the squares of the speeds of particles in an ideal gas
what is the rms speed
the square root of the arithmetic mean value of the squares of the speeds of particles in an ideal gas
what is the formula for average kinetic energy
0.5m<c^2>
what is the formula for average kinetic energy
0.5m<c^2>
what is the formial tha links absolute temp with average Ek
1/2m<c^2> = 3/2kt
how can you prove that the particles are stationary and Absolute zero
1/2m<c^2> = 3/2kt. when the temperature is zero this becomes a situation where the molecules are stationary and have to Ek, and in order for that to happen they need to have an rms speed of zero (i,e speed decrease to zero) since their mass is constant
the fact that average Ek is proportional to temp is a
the assumption within the kinetic theory, this follows consistently from the ideal gas laws, but these are also founded on a set of assumptions
learning tip
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