KINETIC PARTICLE THEOREY

Question 1

define the kinetic particle theory

Answer 1

the kinetic particle theory states that all matter is made up of tiny particles that are in constant random motion.

Question 2

explain why do solids have fixed shapes?

Answer 2

according to the kinetic particle theory:-
1. the particles in solids are arranged in an orderly manner
2. held together by very strong forces of attraction
3. have sufficient KE to only vibrate about their fixed location
4. thus cannot move freely
5. thus fixed shape

Question 3

explain why solids have a fixed volume

Answer 3

the particles in a solid are held very close to each other and cannot be compressed further

Question 4

explain why liquids do not have a fixed shape

Answer 4

according to the kinetic particle theory ,
1. the particles in liquid are arranged in a disorderly manner
2. and held together by relatively weaker forces of attraction (than solids)
3. posses sufficient KE to move freely throughout the liquid
4. thus no fixed shape

Question 5

explain why liquids have a fixed volume

Answer 5

despite the particles being slightly apart from each other, the particles in liquid are still packed quite closely together and cannot be compressed. thus a fixed volume

Question 6

explain why gases do not have a fixed shape

Answer 6

according to the kinetic particle theory,
1. the particles in gases are spread very far apart from each other
2. held together by very weak forces of attraction
3. have a lot of KE and are not held in fixed positions
4. can move freely and rapidly in any direction
5. thus no fixed shape

Question 7

explain why gases have no fixed volume

Answer 7

the particles of gases can be forced to move closer to each other when pressure is applied

Question 8

define melting

Answer 8

the process by which a substance turns into a liquid

Question 9

define melting point

Answer 9

the temperature at which a solid becomes a liquid

Question 10

why doesn’t the temperature increase during melting/boiling?

Answer 10

the heat energy absorbed by the particles is used to overcome the strong forces of attraction

Question 11

why doesn’t temperature decrease during freezing?

Answer 11

heat is given out to surrounding, to strengthen the forces of attraction between the particles

Question 12

A pure substance melts and freezes at the same temperature. true or false

Answer 12

true

Question 13

what happens to a substance during melting (in terms of energy changes)

Answer 13

1. heat energy absorbed by the particles is converted to KE.
2. the particles begin to vibrate faster about their fixed positions.
3. once the temperature is high enough, the particles have sufficient KE to overcome the strong forces of attraction.
4. the particles break free from their fixed positions
5. the substance is now a liquid

Question 14

what happens to a substance during freezing(in terms of energy changes)

Answer 14

1. heat energy is given out to the surroundings.
2. the particles begin to lose KE and begin to move slower.
3. once the temperature is low enough, the particles no longer have KE to move freely throughout the liquid.
4. the particles begin to settle in their fixed positions.
5. after some time, all particles have settled into their fixed position
6. the substance is now a solid

Question 15

define freezing

Answer 15

the process by which a substance turns from liquid to solid

Question 16

define freezing point

Answer 16

the temperature at which a substance turns from liquid to solid

Question 17

define boiling

Answer 17

the process by which a substance turns from liquid to gas

Question 18

define boiling point

Answer 18

the temperature at which a substance turns a gas from the liquid state

Question 19

what happens during boiling(in terms of energy changes)

Answer 19

1. heat is taken in by the particles and converted to KE.
2. the particles begin to move faster throughout the liquid.
3. once the temperature is high enough, the particles overcome the relatively strong forces of attraction holding them together.
4. the particles are now spread far apart
5. the substance is now a gas

Question 20

define evaporation

Answer 20

the process by which a liquid turn into a gas, at a temperature lower than the boiling point .

Question 21

why does evaporation occur

Answer 21

evaporation occurs become some particles at the surface of liquids have sufficient KE to escape into the surroundings as a gas.

Question 22

3 differences between boiling and evaporation

Answer 22

boiling:-
1. occurs at boiling point
2. occurs throughout the liquid
3. occurs rapidly

evaporation:-
1. occurs at any temperature below the boiling point
2. occurs at surface of liquid
3. occurs slowly

Question 23

what happens to the particles of a gas when the gas condenses?

Answer 23

1. heat energy is lost to the surroundings,
2. particles begin to lose KE, and start moving slower
3. once the temperature is low enough, the movement of particles becomes slow enough for the gas to change into a liquid

Question 24

define sublimation

Answer 24

the process by which a solid directly changes into a gas without going through the liquid gas

Question 25

define deposition

Answer 25

the process by which a gas directly changes to a solid without going through the liquid state.

Question 26

give example of substance that sublime

Answer 26

iodine, dry ice(solid CO2), naphthalene, NH4Cl

Question 27

define diffusion

Answer 27

movement of particles from a region of higher concentration to a region of lower concentration

Question 28

how does Mr of gas affect diffusion

Answer 28

the higher the Mr the slower the rate of diffusion

Question 29

how does temperature affect diffusion

Answer 29

temperature increases the rate of diffusion. As temperature increases, the Ke particles posses increases thus the particles begin to move faster