gases Flashcards
Kinetic-Molecular Theory (KMT) of Gases Based on what three assumptions?
- The gas consists of molecules of mass in ceaseless random motion, obeying the laws of classical mechanics
β Particles move at constant velocity in straight lines between collisions (with other particles or container) - The size of the molecules is negligible (their diameters are much smaller than the average distance travelled between collisions)
- Molecules interact only through brief elastic collisions
RMS speed of the gas depends on the ______ of the gas, M, and the gasβs temperature (k)
molar mass
_____ is one number that describes the speed of
molecules with given molar mass and temperature
π£πππ
For _____ temperatures and large masses, low speeds
predominate
low
For ____ temperatures and small masses, the
distribution spreads out toward higher speeds
high
If we know the average speeds of particles, we can figure out the average speed with which they
collide, called the _________
mean relative speed
At constant V, Since π£πππ β π£ππππ β π£πππ β π, collision frequency _______ with temperature
increases
At constant T, the collision frequency is __________ to pressure
directly proportional
At constant T, increasing N or decreasing V would ________ pressure, which would increase collision frequency
increase
Collision frequency _______ with increasing T because the particles are moving faster
increases
Collision frequency _________ with P because the particles are closer together and donβt need to move as far in order
to collide, thus causing more frequent collisions
increases
If n is increased, P will ________ without changing T
increase
If T is fixed but P goes up, π will go down. P and π
are _______ proportional
Inversely
π is ___________ of T
independent
We know the ideal gas law is an approximation
that pretends that what?
1) gas particles do not interact except during collisions
2) gas particles
themselves have no volume
Real gases behave most ideally when P is very _____
and/or T is very high
low
When T is ______ (close to condensation) or P is high, gas behavior deviates significantly from ideality
low
When gas particles are very close, they _____ each
other
repel
When gas
particles are
close, but not
very close,
they ________
each other
attract
Ideal gas particles, with no attractive interactions, would never form a ________ or solid
liquid
Real gases
- Particles actually attract one another
β Particles have non-neglible volume
At large V and high T, the isotherms for real gases
are very similar to those of i____________
deal gases
One correction is in terms of the volume (related to virial equation of state)
β Ideal gas law assumes particles occupy no volume
β vdW equation says particles do occupy volume, which
reduces the free volume particles can travel through
β b is the excluded volume per mole, so the free volume
becomes π β ππ
What does PEMDAS mean?
- Parentheses
- Exponentiation
- Multiplication
- Division
- Addition
- Subtraction