Kinetic molecular theory

Question 1

define intramolecular bond

Answer 1

a bond which occurs between atoms within molecules

Question 2

define intermolecular forces

Answer 2

a weak force of attraction between molecules ions or atoms of noble gases

Question 3

define melting point

Answer 3

the temperature at which a sold becomes liquid

Question 4

define boiling point

Answer 4

the temperature of a liquid at which its vapor pressure equals the external (atmospheric) pressure

Question 5

what is the kinetic molecular theory

Answer 5

all matter is made up of particles (molecules or atoms) that are in constant motion

Question 6

define temperature

Answer 6

the measure of the average kinetic energy

Question 7

what is kinetic energy

Answer 7

energy of motion

Question 8

what is Brownian motion

Answer 8

the random (constant) movement of particles in a gas or liquid

Question 9

define diffusion

Answer 9

the random movement of particles from a high concentration to a low concentration with no mechanical aid until equilibrium is reached

Question 10

define matter

Answer 10

anything that has mass and occupies space

Question 11

define sublimation

Answer 11

the transformation from solid to gas phase or vice verse bypassing the liquid phase

Question 12

define evaporation

Answer 12

when the particles of the liquid escape from the surface to form vapor (gas)

Question 13

define condensation

Answer 13

vapor particles attract each other to form a liquid

Question 14

define freezing

Answer 14

particles of the liquid rearrange themselves under forces of attraction to form a solid

Question 15

when does temperature increase during phase change

Answer 15

when energy is taken in (absorbed)

Question 16

why is phase change not a chemical change

Answer 16

because the chemical composition is not altered and no new substance is formed

Question 17

what can melting point be used to do

Answer 17

to determine the purity of a substance

Question 18

what is latent heat

Answer 18

heat used to overcome the intramolecular forces

Question 19

what is the MP and BP of water

Answer 19

MP-0

BP- 100 at sea level

Question 20

Name 3 substances that sublimate

Answer 20

pure carbon dioxide
moth balls
iodine

Question 21

define pressure and state what it is measured in

Answer 21

force per unit area

measured in pascals

Question 22

what does the state of a substance depend on

Answer 22

kinetic energy of particles

the strength of the intermolecular forces between particles

Question 23

a gas to a solid is known as

Answer 23

deposition

Question 24

the higher the temperature of a substance_______

Answer 24

the faster the particles are moving

Question 25

give 3 characteristics of a solid

Answer 25

``` particles are bonded in fixed positions strong forces between particles small space between particles particles vibrate about their rest position not easily compressible ```

Question 26

give 3 characteristics of a liquid

Answer 26

particles can move over one another forces between particles weaker than in solids spaces between particles are slightly larger than in solids particles move about more vigorously not easily compressible

Question 27

give 3 characteristics of a gas

Answer 27

``` particles are far apart virtually no forces between particles large spaces between gas particles particles move around at high speed compressible ```

Question 28

if temperature is below melting point what phase is the pure substance in

Answer 28

solid phase

Question 29

if temperature is above melting point what phase is the pure substance in

Answer 29

liquid phase

Question 30

if temperature is above boiling point what state is the pure substance in

Answer 30

gas phase

Question 31

when does phase change occur with a substance and its particles

Answer 31

when its particles gain or lose kinetic energy (temperature)

Question 32

according to the kinetic molecular theory why does the temperature remain constant during phase change

Answer 32

temp remains constant as energy is absorbed by particles and used to overcome the forces between particles, particles are gaining kinetic energy