2 - Gases, Kinetics, and Chemical Equilibrium

Question 1

Standard Temperature and Pressure (STP)=

Mean free path=

***unlike liquids, all gases are miscible with each other, they mix regardless of ______. But at low temperatures and with time heavier gases tend to ______ below lighter gases.***

Answer 1

Standard Temperature and Pressure (STP)= 0 degrees Celsius and 1 atm.

Mean free path= the distance traveled by a gas molecule between collisions.

***unlike liquids, all gases are miscible with each other, they mix regardless of polarity. But at low temperatures and with time heavier gases tend to settle below lighter gases.***

Question 2

Kinetic molecular theory=

Ideal gas follow these four characteristics not shared by real gas:
1)
2)
3)
4)

Answer 2

Kinetic molecular theory= an ideal gas lacks certain real gas characteristics.

Ideal gas follow these four characteristics not shared by real gas:

1) zero volume
2) gas molecules exert no forces other than repulsive forces due to collisions
3) gas molecules make completely elastic collisions
4) average kinetic energy of gas molecules is directly proportional to the temperature of the gas

Question 3

Ideal gas law:
***at STP one mole of any gas (behaving ideally) will occupy the standard molar volume of _____ liters.

Partial pressure: Pa =

Dalton’s Law: P total =

Answer 3

Ideal gas law: PV = nRT
***at STP one mole of any gas (behaving ideally) will occupy the standard molar volume of 22.4 liters.

Partial pressure: Pa = Xa*Ptotal

Dalton’s Law: P total = P1 + P2 + P3…
K.E.avg = 3/2RT

Question 4

Graham’s law:

Effusion=

Diffusion=

Real VS Ideal (Volume)

Real VS Ideal (pressure)

Answer 4

Graham’s law: (v1/v2) = ((sq rt m2)/(sq rt m1))

Effusion= is the spreading of a gas from high pressure to very low pressure through a “pinhole”
Effusion rate 1/effussion rate 2 = (sq rt m2)/(sq rt m1)

Diffusion= is the spreading of one gas into another gas or into empty space.

V real > V ideal

P real < P ideal

Question 5

Collision Model=

Activation Energy=

***The rate of a reaction increases with _____ mainly because more ______ with sufficient relative kinetic energy occur each second.***

Intermediates=

Rate law=

Rate forward=
a+b =

Answer 5

Collision Model= a method for visualizing chemical reactions.

Activation Energy= relative kinetic energies of the colliding molecules must reach a threshold energy.

***The rate of a reaction increases with temperature mainly because more collisions with sufficient relative kinetic energy occur each second.***

Intermediates= are species that are products of one reaction and reactants of a later reaction in a reaction chain.

Rate law=

Rate forward= Kf [A]a[B]b
a+b = overall order of the reaction.

Question 6

Zero order graph=

First order graph=

Second order graph=

Third order graph=

Answer 6

Zero order graph= very steep negative slope.

First order graph= not as steep negative slope.

Second order graph= steep positive slope.

Third order graph= not as steep positive slope.

Question 7

Rate determining step=

Catalyst=

Heterogeneous catalyst=

Homogeneous catalyst=

Answer 7

Rate determining step= the rate of the slowest elementary step determines the rate of the overall reaction and is the rate determining step.

Catalyst= is a substance that increases the rate of a reaction without being consumed or permanently altered; catalyst creates a new reaction pathway which typically includes an intermediate.

Heterogeneous catalyst= is in a different phase than the reactants and products.

Homogeneous catalyst= is in the same phase as the reactants and products, usually in the gas or liquid phase.

Question 8

Le Chatelier’s principle=

Answer 8

Le Chatelier’s principle= states that when a system at equilibrium is stressed, the system will shift in a direction that will reduce that stress.