chapter 2 - kinetic particle theory

Question 1

what does the kinetic particle theory state

Answer 1

• all matter is made up of tiny particles
• these particles have kinetic energy
• particles are in constant random motion

Question 2

movement of solid, liquid, and gas

Answer 2

solid- vibrate and rotate about fixed position
liquid - slide past one another feely throughout liquid
gas - moves quickly and randomly in any direction

Question 3

energy of particles

Answer 3

solid - very low
liquid - low
gas - high

Question 4

according to particle theory, explain the shape of solid, liquid, and gas

Answer 4

solid - (fixed shape) particles can only vibrate and rotate at their fixed positions; are held together by very strong forces of attraction\

liquid - (no fixed shape) particles can slide past one another; weaker forces of attraction as compared to solids

gas - particles move quickly and randomly in any direction; held by weak forces of attraction

Question 5

according to particle theory, explain the volume of solid, liquid, and gas

Answer 5

solid - (fixed volume) very closely packed; very little empty space

liquid - (fixed volume) closely packed; very little empty space

gas - (no fixed volume) far apart; large empty space

Question 6

changes in state and explanation: heating

Answer 6

heating - thermal energy is converted to kinetic energy of the particles

Question 7

changes in state and explanation: melting

Answer 7

melting - solid is heated, thermal energy is converted to kinetic energy of the particles;
particles then vibrate and rotate about their fixed position;
at melting point, the vibrations become vigorous enough to over the strong attractive forces that hold the particles in fixed positions;
particles then break away from fixed positions,, able to slide over one another

Question 8

changes in state and explanation: boiling

Answer 8

boiling- liquid is heated, thermal energy converts to kinetic energy of the particles;
slide past one another with increasing speed;
at boiling point, the particles throughout the liquid gain enough energy to overcome the strong attractive forces holding them together;
particles are now far apart and move quickly in all directions

Question 9

changes in state and explanation: evaporation

Answer 9

evaporation - when a substance changes from liquid to gas state below the boiling point;
particles have enough energy to escape from the surface of the liquid to form a gas

Question 10

changes in state and explanation: freezing

Answer 10

freezing - liquid is cooled, kinetic energy of the particles is converted to thermal energy which is transferred to the surrounding;
particles lose kinetic energy and begin to move more slowly;
at freezing point, the particles no longer have enough energy to move about freely;
now orderly arranged and can only vibrate and rotate in their fixed positions

Question 11

changes in state and explanation: cooling

Answer 11

cooling - kinetic energy is converted to thermal energy which is transferred to the surrounding

Question 12

changes in state and explanation: condensation

Answer 12

condensation - thermal energy is transferred to the surrounding;
particles lose kinetic energy, begin to move more slowly;
at low temp, particles no loner have enough energy to move about freely;
attractive forces pull the particles closer to one another;
movement of particles becomes slow enough for gas to change to a liquid

Question 13

changes in state and explanation: sublimation

Answer 13

sublimation - particles at the surface of the solid have sufficient energy to break away from the solid and escape as gas;
solid changes to gas directly without liquid state;
solid particles gain thermal energy to overcome very strong attractive forces;
particles move far apart freely at high speeds in all directions

Question 14

explain why points b to c are the same temperature while change of state

Answer 14

during melting, temperature remains constant even though heating continues;
thermal energy taken in from surrounding is used to overcome attractive forces holding the solid particles together instead of being used to raise the temperature

Question 15

diff between evaporation and boiling

Answer 15

evaporation:
- any temperature below boiling point
- site is on surface of liquid
- slow

boiling:
- at boiling point (for pure substances)
- throughout the liquid
- fast

Question 16

explain why points q to rwa2 are the same temperature while change of state

Answer 16

during freezing, the temperature remains constant;
thermal energy is released to the surroundings when the particles become closer and are attracted to one another;
particles slow down to take up fixed and orderly positions in the solid