kinetic molecular theory postulates
gas molecules are _________ _____ compared to the distances between them.
“negligibly small”
if temp increases, what happens to pressure?
if T inc, P inc (kinetic E/speed inc due to more collisions but V is constant)
when are gases NOT considered ideal anymore? (don’t explain why)
high pressure and low temp
what are the STP conditions?
P= 1.000 atm and T=273.15K
name 3 general characteristics of a gas
compressible, expandable, low viscosity, low density, miscible, varying volume with temp/pressure
what is the average kinetic energy of gas molecules directly proportional to?
the kelvin temperature of the gas
if temp increases, what happens to volume?
if T inc, V inc (to keep P constant)
is P real higher or lower than P ideal? Why?
P real= lower because the IMF from other molecules disrupt travel pathways from being perfectly straight, so collisions are less frequent
what are the 2 ideal gas conditions?
1. gas molecules have negligible volume compared to container size 2. gas molecules have negligible forces b/w them
do bigger molecules travel faster or slower than smaller molecules?
bigger molecules travel slower
what are 3 qualities of gas molecules? think of:
1. motion 2. travel pathway 3. travel direction
1. they are in constant motion 2. they travel in straight lines 3. they change direction when they collide w/ other molecules or container walls
if volume increases, what happens to pressure?
if V inc, P decreases (because larger space=less collisions)
explain the 2 conditions that make gases non ideal. (think about what’s happening on a molecular level)
high P —> the gas is very compressed so the space b/w molecules is not negligible anymore AND the molecules are close together so feel IMF
low T —> molecules move very slow so they can feel the IMF forces b/w one another
how do you convert celsius (°C) into kelvin (K)?
_____°C + 273.15K
what’s the difference b/w diffusion and effusion?
diffusion: gradual mixing of molecules of one gas with molecules of another
effusion: gas under pressure escapes from one container to another through a small opening
___ ________ is a result of collisions b/w gas molecules and container walls
“gas pressure”
if the mols of gas (n) increases, what happens to pressure?
if n inc, P inc (due to more collisions)
is the volume available for real gases more or less than ideal gases?
V available=less because the molecules don’t have negligible volume
what 2 things do you need to watch out for when calculating Urms?
R=8.314 (instead of 0.08206), and mass must be in Kg (instead of grams)
what happens to the pressure exerted by one gas if a new gas is introduced into the container? (assume temp and volume remain constant)
the pressure exerted by the original gas is unaffected because each gas behaves independently and does not interact with other gases — it “doesn’t know” the others are present
what forces do gas molecules exert on each other/the container? what kind of collisions does this cause?
no forces are exerted, so the collisions are elastic (no energy is lost)
if the mols of gas (n) increases, what happens to volume?
if n inc, V inc (to keep P constant)
is the volume required for real gases more or less than ideal gases?
V required=more because it must account extra space for the NON-negligible volume of the molecules
if you’re provided with 1 mol of an ideal gas at STP, what is its volume?
22.4 L
if the temp is increased, what happens to the mol fractions in a gas mixture?
nothing happens! mol fractions stay the same because they depend only on the number of moles of each gas, not temperature. even though total pressure increases with temperature, the proportion of each gas in the mixture doesn’t change.