Unit 2

Question 1

How is pressure inside containers created

Answer 1

gas particles collide with the walls

Question 2

how does increasing temperature affect pressure inside containers

Answer 2

increases the velocity of particles which increases pressure

Question 3

what happens to the pressure when volume of a container is decreased

Answer 3

the number of collisions increase so pressure increases

Question 4

what happens to particles at absolute zero

Answer 4

they have no kinetic energy
this is found at -273 celsius or 0 kelvin

Question 5

what is brownian motion

Answer 5

the random collisions between microscopic particles in a suspensions and the particles of gases or liquids

Question 6

what happens when a material is heated

Answer 6

it expands

Question 7

what happens when a solid is heated

Answer 7

the particles will vibrate more and push each other further apart

Question 8

what happens to the temperature when a substance changes state

Answer 8

there is no change to temperature

Question 9

what is the boiling and melting point of water

Answer 9

boiling is 100 C
melting is 0 C

Question 10

what happens during evaporation

Answer 10

particles escape from a liquid surface causing it too cool

Question 11

why is the expansion of different states different

Answer 11

gases expand the most
liquids expand more than solids
solids expand the least because their bonds are strongest

Question 12

what is the specific heat capacity

Answer 12

the energy required to change the temperature of 1 kg of a substance by 1 C
the higher the heat capacity, the more energy it takes to raise the temperature

Question 13

specific heat capacity formula

Answer 13

C = change in energy
—————————
mass X change in temperature

Question 14

what happens when liquids are heated

Answer 14

the fastest particles escape first, the average energy of the remaining particles decrease which causes a decrease in temperature

Question 15

what is the difference between evaporation and boiling

Answer 15

evaporation only happens at the surface and at any temperature
boiling happens throughout the liquid at the boiling point

Question 16

how does surface area affect evaporation

Answer 16

rate of evaporation increases as surface area increases

Question 17

how is energy transferred

Answer 17

thermal conduction through materials

Question 18

how do convection currents transfer energy within a fluid

Answer 18

due to density changes
hot materials expand and rise then cool and contract

Question 19

what are convection processes responsible for

Answer 19

air currents

Question 20

what happens when object absorb and emit infrared radiation

Answer 20

causes them to warm or cool

Question 21

how does infrared radiation get transferred

Answer 21

doesnt require a medium

Question 22

what factors affect the amount of radiation emitted or absorbed

Answer 22

surface color( dark surfaces emit and absorb better than light surfaces)
surface texture( matt and rough surfaces are better than smooth and shiny)

Question 23

why are nonmetals bad conductors

Answer 23

conduction is slow since energy is passed through vibration
metals conduct much faster since they have free electrons

Question 24

why are gases poor conductors

Answer 24

particles are too far apart to pass energy

Question 25

are liquids good conductors

Answer 25

they are fairly poor since their particles are less tightly packed

Question 26

when objects emit more radiation than they absorb, waht are they doing

Answer 26

cooling down

Question 27

objects that absorb more radiation they they emit,what are they doing

Answer 27

warming up

Question 28

what does rate of emisson depend on

Answer 28

temperature- the higher the temperature difference, the more radiation will be emitted
surface area- the larger the area the more energy can be absorbed or emitted

Question 29

what is the formula for latent heat

Answer 29

amount of heat absorbed or released per unit mass

Question 30

what is latent heat

Answer 30

energy released or absorbed during a change in state