Mcat Chemistry Lecture 2

Front 1

Ideal gas law -

Back 1

PV = nRT
P = pressure
V = Volume
n = number of moles of gas
R = ideal gas constant
T = temperature

Front 2

R in SI units is ____, Otherwise it is ____.

Back 2

8.314 joules /Kelvin*mole
0.08206 L*atm/ Kelvin*mole

Front 3

Molecules are ____ in diameter

Back 3

3-6 angstroms

Front 4

Angstrom = ____

Back 4

10^-10 m

Front 5

Sound is a wave via colliding _____, wave can only move as fast as the speed of the molecules, the speed of the molecules is close to the speed of ____ (340 m/s) so the average speed of molecules is about _____ (____)

Back 5

air molecules
sound
540 m/s (1000mph)

Front 6

Room temp at 1 atm, molecules are typically ____ diameters apart
Gas molecules are about ____ angstroms apart

Back 6

6-12
35

Front 7

____ = a hypothetical gas that differs from a real gas in 4 ways

Back 7

Ideal gas

Front 8

ideal gas deviations

Back 8

NMCT
Molecules have no volume,
No attractive forces on each other
Collisions between molecules are completely elastic, no mechanical energy is lost, kinetic energy before and after the collision is the same (can think of them as tiny hard pool balls)
Temperature varies directly with the average kinetic energy of the molecules, double the temp double the average kinetic energy

Front 9

STP = ____

Back 9

1 atm and 0* Celsius

Front 10

From ideal gas law, if pressure and temperature are fixed ____ gas will have same volume at STP

Back 10

1 mole of any

Front 11

Volume of a mole of gas at STP -

Back 11

22.4 L = Standard Molar Volume

Front 12

____ is what it would produce if it was in the container by itself.

Back 12

Partial pressure

Front 13

____ = the number of that gas in question times the total amount gas

Back 13

Mole fraction

Front 14

____ = the total pressure is the sum of the partial pressures of each of its gases

Back 14

Daltons law

Front 15

____, partial pressure of any gas is the total pressure times the mole fraction of that gas

Back 15

Daltons law

Front 16

Gasses that behave ideally essentially lose their identity when it comes to ____, ____ and _____, so 1/2 a mole of helium and 1/2 a mole of nitrogen in a 22.4L container at 0* Celsius the mixture will be 1 atm. Can say helium contributes ____ an atm and nitrogen ____ an atm.

Back 16

pressure
volume
temperature
1/2
1/2

Front 17

Any fluid system, the ____ is proportional to the temperature.

Back 17

kinetic energy

Front 18

Uniform kinetic temperature does not add to the temperature, talking about ____.

Back 18

random motion

Front 19

Kinetic energy =

Back 19

3/2 RT
R = ideal gas constant
T= temperature in Kelvins
& = 1/2 MV^2

Front 20

Grahams law =

Back 20

V1/V2 = m2^.5 / m1^.5

Front 21

____ - spreads out over a space, or though another gas (perfume)

Back 21

Diffusion

Front 22

____ is the process by which gas move from a high pressure system to a low pressure system through a "pinhole" - a hole smaller than the average distance between two molecules

Back 22

Effusion

Front 23

____ therefore effuse and diffuse more quickly.

Back 23

Lighter gases

Front 24

The rate of these are proportional to the average speed of the molecules, so ____ gives the ratio of the rates of effusion or diffusion for two gasses

Back 24

grahams law

Front 25

So have deviations when the molecules are closer together - so at ____ and ____ real gases deviate from ideal gas behavior

Back 25

high pressures
low temps

Front 26

Deviations from ideal gas behavior, ____ and ____ should come to mind

Back 26

pressure
volume

Front 27

____ for a real gas is greater because we have molecule size

Back 27

Volume

Front 28

Real gas molecules exert attractive forces on each other = weaker collisions =
____ for real gas than ideal gas predictions

Back 28

less pressure

Front 29

Initial ____ is the change of concentration of the reactants per unit time

Back 29

reaction rate

Front 30

Rate of ____ and probability of ____ are two separate things

Back 30

reaction
occurence

Front 31

____ - sufficient energy to break bonds

Back 31

Activation energy

Front 32

In order for a reaction to occur molecules must ____ - energy from a collision can be used to _____

Back 32

collide
break bonds

Front 33

____ = increase in the speed of the molecules = increase in energy of collisions
Rate constant and thus the rate itself always increases with ____

Back 33

increase in temp
increasing temperature

Front 34

The Arrhenius equation - the rate constant is proportional to three things:

Back 34

#, /, ori!
the number of collisions,
the fraction of collisions with enough energy to react and
the fraction of these collisions that collide with the correct orientation.

Front 35

____ = number of molecules that collide to create a reaction

Back 35

Molecularity

Front 36

____ = coefficients indicate the exact number

Back 36

Elementary reaction

Front 37

The ____ is equal to the rate constant times the _____ of the reactions to some exponent
The exponent is from the ____ if the reaction is elementary

Back 37

rate
concentration
coefficient

Front 38

____ = rate determining step

Back 38

Slow step

Front 39

____ = if we remove heat from a reaction that produces heat the equliibrium will respond by moving to the right to produce more heat, if we add heat it will shift to the opposite direction.

Back 39

Le Chatelier's principle

Front 40

Le Chatelier's principle

Back 40

The equilibrium will shift to the opposite of the stuff added. (more products shift left, more reactants shift right)

Front 41

Both the ____ and the ____ increase with temp, the ____ always increase, but the ____ depends mainly on whether or not the reaction absorbs or releases heat.

Back 41

rate constant
equilibirum constant
rate constant
equilibirum constant

Front 42

____ = Q = to find q we use same equation of the equilibrium constant,

Back 42

Reaction quotient

Front 43

If Q = K, then it is at _____, if it is smaller then K the reaction will move ____ until it _____ to K, if it is larger than K it will move in the ____ until it is the ____ as K.

Back 43

equilibrium
forward
increases
reverse
same size

Front 44

____ is a type of balancing - as a reaction progresses reactants are used up and more and more products are formed , the reverse reaction rate increases and the forward reaction rate decreasees
Eventually the rates ____ and this point is called ____.

Back 44

Equilibrium
equalize
Equilibrium

Front 45

At _____ the rates of the forward and reverse reactions are equal, though this does not mean the ____ are equal.

Back 45

Equilibrium
concentrations

Front 46

K = ____ = concentrations of the products taken to their reaction coefficients divided by the concentration of the reactants divided by their coefficients

Back 46

equilibrium constant