Chem chp 2

Question 1

What is the definition of matter?

Answer 1

Matter is a substance that has mass and occupies space. All living and non-living things are matter.

Question 2

What state is dry ice considered to be in?

Answer 2

Solid

Question 3

What are the three main states of matter?

Answer 3

Solid, liquid and gas

Question 4

State the particle arrangements for the 3 states of matter

Answer 4

Solid-packed in close and orderly manner
Liquid-closely packed in disorderly manner
Gas- very far apart in disorderly manner

Question 5

State the attractive forces between particles of the 3 states of matter

Answer 5

Solid- Very strong
Liquid-Less strong
Gas-Very weak

Question 6

State the kinetic energy of particles of the 3 states of matter

Answer 6

Solid- very low
Liquid- low
Gas- high

Question 7

What is the particle movement of solids?

Answer 7

Vibrate and rotate about fixed positions

Question 8

What is the particle movement of liquids?

Answer 8

Slide past one another freely throughout the liquid

Question 9

What is the particle movement of gases?

Answer 9

Move quickly and randomly in any direction

Question 10

Define transition temperatures

Answer 10

Transition temperatures are the specific temperatures where heating or cooling of a substance results in ** changes of state** instead of changes in temperatures.

Question 11

What is temperature?

Answer 11

The measure of the average kinetic energy of particles in a substance.

Question 12

What happens during changes of state (energy-wise)?

Answer 12

Temperature remains constant as the avg KE of particles does not change.
Thermal energy->CPE and vice versa

Question 13

Describe melting

Answer 13

KE gained->particles in solid vibrate and move faster when heated
sufficient energy
->overcome forces of attraction holding them in their fixed positions and move around one another randomly.

Question 14

Describe freezing

Answer 14

Particles in liquid slow down
Thermal energy lost to surroundings when liquid is cooling->KE decreases
Particles eventually settle into fixed positions in an orderly arrangement
Solid is formed

Question 15

Describe expansion

Answer 15

Solid heated at temps below boiling pt-> cannot spread out freely, strongly attracted
Vibrate more quickly, but with wider spacing

Question 16

Describe contraction

Answer 16

When solid is cooled, thermal energy is transferred from the particles to the surroundings
Particles possess less kinetic energy
->vibrate slower and closer

Question 17

Define evaporation

Answer 17

The process by which a liquid changes to a gas at temperatures lower than its boiling point.

Question 18

Define boiling

Answer 18

The process by which s liquid changes to a gas throughout the liquid at the boiling point of the substance.

Question 19

Describe evaporation

Answer 19

At surface of liquid (in contact with air)-> enough KE to overcome attractive forces
‘Escapes’ liquid as vapor

Question 20

At what temperature does evaporation occur

Answer 20

At all temperatures

Question 21

Where in the liquid does evaporation occur?

Answer 21

At the surface, when only some particles have enough energy to escape as a gas

Question 22

Describe boiling
CLUE: talk ab energy transfer and forces of attraction

Answer 22

thermal energy transferred (at boiling pt.)-> gain KE->Particles in liquid move faster
gain sufficient energy->completely overcome forces of attraction holding them tgt

Question 23

What are the differences between evaporation and boiling?

Answer 23

where it occurs-> on surface (evaporation) vs throughout entire liquid (boiling)
what temp it occurs at-> any temp (evaporation) vs only at boiling pt (boiling)
speed-> slow process (evaporation) vs fast process (boiling)

Question 24

Define condensation

Answer 24

The process by which a gas changes to a liquid

Question 25

Describe condensation

Answer 25

Gas is cooled, KE-> thermal energy transferred to surroundings Spacing between particles reduces when cooling->volume of gas decreases gas contracts until particles **come close enough form a liquid**

Question 26

When does condensaion occur?

Answer 26

When water vapour touches a cold surface

Question 27

What does liquifying gases do?

Answer 27

Shrinks volume of substance by a significant amount, makes it easy for storage

Question 28

Define sublimation

Answer 28

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

Question 29

Define vapour disposition

Answer 29

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

Question 30

Describe sublimation

Answer 30

**Thermal energy from surroundings** ->more **KE** **Particles at surface** of solid have enough **KE **to **break away from solid and escape as gas**

Question 31

Describe vapour disposition

Answer 31

Particles in gas cool until they slow down and arrange themselves directly into solid state

Question 32

What is the effect on molecular mass on diffusion?

Answer 32

greater Rmm, particles move slower and rate of diffusion is slower smaller Rmm, particles move faster and rate of diffusion is faster