First Test

Question 0

What observation supports the KMT postulate that states: particle motion is random

Answer 0

Pressure is uniform in all directions

Question 1

What observation supports the KMT postulate that states: particles are very far apart

Answer 1

IGL only works at low gas densities

Question 2

What observations support the KMT postulate that states: gas particles do not interact

Answer 2

IGL is independent of particle type and Dalton’s Law of Partial Pressures

Question 3

Postulates of the KMT?

Answer 3

1) gas particles are in constant random motion
2) pressure is due to particle collisions with walls of container
3) gas particles are very far apart
4) gas particles do not exert forces on each other (due to being far apart)

Question 4

What two laws does KMT come from?

Answer 4

IGL and Dalton’s LoPP

Question 5

When is the IGL not valid?

Answer 5

At high densities and pressures

Question 6

For a fixed T, the speed of gas molecules depends on…

Answer 6

The molecular mass of the gas

Question 7

For a fixed T, total KE for one mole is….

Answer 7

The same for all gases

Question 8

What two factors is P dependent on?

Answer 8

1) frequency of collisions

2) how hard the collisions are

Question 9

Why does increasing density increase pressure?

Answer 9

Because it increases the frequency of the particles hitting the walls of the container

Question 10

Why does increasing T increase P?

Answer 10

Increasing T increases the speed of the molecules and thus the frequency as well

Question 11

Negative deviations from IGL

Answer 11

As density (n/V) increases, observed P is less than P predicted by IGL (nRT/V)

Question 12

Negative deviations from the IGL occur because of…

Answer 12

Intermolecular attractions that decelerate particles by attracting particles to other particles

Question 13

Positive deviations of the IGL are caused by…

Answer 13

Intermolecular repulsions that accelerate the particles

Question 14

Negative deviations do what to P

Answer 14

Lower Pressure relative to IGL predictions

Question 15

Positive deviations do what to P

Answer 15

Increase pressure relative to IGL predictions

Question 16

What is mean free path

Answer 16

The average distance a particle will travel before hitting another particle

Question 17

The rate of a chemical reaction can be no greater than….

Answer 17

The rate at which the particles run into each other

Question 18

Reaction rate is proportional to…

Answer 18

reactant concentration

Question 19

If rate doubles when concentration doubles?

Answer 19

n=1

Question 20

If rate quadruples when concentration is doubled

Answer 20

n=2

Question 21

First order

Answer 21

Rate=k[A]

Question 22

Second order

Answer 22

Rate=k[A]^2
Or
Rate=k[A][B]

Question 23

Why does increasing temp, increase the rate of the reaction

Answer 23

Because according to KMT, increase in T is equal to an increase in kinetic energy. Therefore, as T increases, the fraction of molecules with sufficient energy to surmount the reaction activation barrier increases.

Question 24

Activation energies are much, much ____ than bond energies. Why?

Answer 24

Lower.

Because bonds are broken and formed at the exact same instant in reactions

Question 25

The sequence of elementary processes leading to the overall reaction is referred to as the…

Answer 25

Reaction mechanism

Question 26

The slowest step in a multi-step process is called the….

Answer 26

Rate-determining or rate-limiting step

Question 27

Is made then consumed in a rxn

Answer 27

Intermediate

Question 28

Is consumed then regenerated in a rxn

Answer 28

Catalyst

Question 29

IF reaction occurs in a single collision, order of the reaction is determined by the stoichiometry. THEREFORE:

Answer 29

IF the rate law differs from the stoichiometry, the reaction does not occur in a single collision.

Question 30

In reaction mechanisms, the overall rate of the reaction is determined by….

Answer 30

The rate determining (slow) step

Question 31

The collision rate does not equal…

Answer 31

The reaction rate

Question 32

What else is required for a reaction to occur BESIDES a collision?

Answer 32

Sufficient energy
Appropriate orientation
Random factors (phase of molecular vibrations)

Question 33

Even for exothermic reactions ____ is still required

Answer 33

Activation energy

Question 34

Boyle’s Law

Answer 34

Pressure and volume are inversely related, as P goes up, V goes down, at fixed T and n

Question 35

Charles law

Answer 35

Volume and temperature are directly related, as volume increases so does temperature, at fixed P and n

Question 36

Avogadro’s Law

Answer 36

Volume and number of moles are directly related, as V increases so does n, at fixed T and P

Question 37

Dalton’s law of partial pressures

Answer 37

The total pressure exerted in a mixture of gases is equal to the sum of the partial pressures of the individual gases.