8.5-10.1 exam/final

Question 1

gas diffursion

Answer 1

high to low concentration

Question 2

mean free path

Answer 2

avg. distance travled by a molecule between collisions

Question 3

Mean free path at sea lvl

Answer 3

60 nm

Question 4

mean free path at 100 km altitude

Answer 4

10 cm

Question 5

mean free path increase with

Answer 5

decreasing pressure

Question 6

gas effusion

Answer 6

transfer of gaseous atoms or molecule from a container to a vaccum through very small openings

Question 7

At a given temperature, lighter particles travel

Answer 7

faster then heavier particles

Question 8

Kinetic Molecular Theory: Postulates

1-Gas molecules are in

Answer 8

continuous motion, travelling in straight lines
and changing direction only when they collide with other molecules
or with the walls of the container

Question 9

Kinetic Molecular Theory: Postulates

2-Volume occupied by gas particles is

Answer 9

SMALL compared to the volume
of the container itself. The molecules composing the gas are
negligibly small compared to the distances between them.

Question 10

Kinetic Molecular Theory: Postulates

3-The pressure exerted by a gas in a container results from

Answer 10

collisions
between the gas molecules and the container walls

Question 11

Kinetic Molecular Theory: Postulates

4:Gas molecules exert

Answer 11

no attractive or repulsive forces on each other or
the container walls; therefore, their collisions are elastic (do not
involve a loss of energy).

Question 12

Kinetic Molecular Theory: Postulates

5:The average kinetic energy of the gas molecules is

Answer 12

proportional to the
temperature (in Kelvin).

Question 13

AMONTONS LAW

temp increased volume constand

Question 14

Gases behave ideally when: The volume of gas particles is

Answer 14

small compared to
the space between them.

Question 15

Gases behave ideally when:The intermolecular forces between

Answer 15

gas particles
are not significant.

Question 16

ideal behavior occurs: At High

Answer 16

pressure
Actual Volume of gas atoms
greater than predicted

Question 17

Non-ideal behavior occurs: at low

Answer 17

temps
actual pressure is less than predicted

Question 18

intermolecualr

Answer 18

Attractive forces that exist
between all molecules and
atoms

Strength of the forces
determines the state of matter

Intermolecular forces are strong
enough to control physical
properties such as boiling and
melting points, vapor pressures,
and viscosities

Question 19

intramolecular

Answer 19

within’

intramolecualr foreces keep a molecule intact

Question 20

The STRONGEST intermolecular force, however,

Answer 20

is still weaker than
bonding forces!

Question 21

Dispersion Forces

Answer 21

London dispersion forces, or
dispersion forces, are attractions
between an instantaneous dipole
and an induced dipole.

These forces are present in all molecules, whether they are polar
or nonpolar.

polarizability

Question 22

polarizability

Answer 22

The tendency of an electron cloud to distort in this way is called
polarizability.

Question 23

Factors Affecting
Dispersion Forces

Answer 23

The strength of
dispersion forces tends
to increase with
increased molecular
weight.
* Larger atoms have larger
electron clouds that are
easier to polarize
-Therefore the greater
strength of dispersion
forces results in
increased boiling
points.
* The shape of the molecule
also affects the strength of
dispersion forces: long,
skinny molecules (like n-
pentane) tend to have
stronger dispersion forces
than short, compact ones (like
neopentane).
* This is due to the increased
surface area.

Question 24

Dipole-dipole Forces

Answer 24

• Molecules that have permanent dipoles are attracted to each other.
• The positive end of one is attracted to the negative end of the other, and vice
  versa.
• These forces are only important when the molecules are close to each other.

Question 25

The more polar the molecule, the

Answer 25

higher its boiling point!
This is due to the increased strength of the dipole-dipole forces