GenChem7 (The Gas Phase) Flashcards
Name 3 ways that gas pressures are expressed in units
1 atm=760 mm Hg = 760 torr
What is STP
1 atm
0° C, or 273 K
What is the condition of standard conditions?
25°C or 298K
A hypothetical gas whose molecules have no IM forces and occupy no volume.
Ideal Gas
What is the equation for the Ideal Gas Law
PV=nRT
How much volume does 1 mole of gas have, regardless of what molecule it is?
22.4 L
What are the equations for density of a gas substance?
d=m/v=P*(MM)/RT
What equations relate changes in the temperature, pressure, and volume of a gas?
(P1V1)/T1 = (P2V2)/T2
Set up the equations for the density of HCL gas at 2atm and 45°C
22.4L/mol * (1atm/2atm) *(318K/273K) = 13.0L mol
d= (36g/mol)/(13.0L/mol)= 2.77 g/L
What is the molar mass of a 2L sample of a gas that weighs 8g at 15°C and 1.5atm?
d=8g/2L at 15°C and 1.5 atm
V(stp)= 2L * (273K/288K)(1.5atm.1atm) = 2.84 L
8g/2.84L = 2.82g/L at STP
2.82g/L * 22.4L/mol = 63.2 g/mol
Under what conditions do gases not behave ideally?
What property causes this behavior?
Extremely high pressure Low temperature (condensation)
IM forces become stronger as molecules are closer together
What is the equation for the partial pressure of a gas in a mixture?
Pa = P(total) * (moles of a)/(total moles)
Part of kinetic molecular theory of gases,
Gases are made up of particles whose volumes are ____ compared to the container volume
Negligible
Part of kinetic molecular theory of gases,
Gas atoms or molecules exhibit no _____ attractions or repulsions
Gas atoms or molecules exhibit no intermolecular attractions or repulsions
Part of kinetic molecular theory of gases,
Gas particles are in continuous __________, undergoing collisions with other particles and the container walls
Random Motion
Part of kinetic molecular theory of gases,
Collision between any two gas particles are ____, meaning that there is no overall gain or loss of energy
Elastic
Part of kinetic molecular theory of gases,
The average kinetic energy of gas particles is proportional to the _______ of the gas, and is the same for all gases at a given ______
Temperature
What are the equations for the average kinetic energy of gases?
KE=1/2mv^2 = 3/2kT
T is the absolute temperature
This occurs when gas molecules diffuse through a mixture
Do light or heavy gas molecules diffuse more quickly?
Diffusion
Light molecules because of average kinetic energy theory
The equation for the rates at which two gases diffuse and effuse
r1/r2 = sqrt(MM2/MM1)
The flow of gas particles under pressure from one compartment to another through a small opening
Effusion.
