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Flashcards in Change of State Deck (33):
1

what are the three states of matter?

solid

liquid

gas

(plasma - don't need to know/use this one)

2

what is the arrangement of a solid?

strong forces of attraction hold the particles close together in a regular lattice

uniform, regular arrangement

don't have much energy, so can oly vibrate about a fixed point

closely packed

strong bonds

can't be compressed

3

what is the arrangement of a liquid?

weaker forces of attraction between the particles

irregular, random arrangement

must be touching

slide over each other

more free to move than a solid as they have more energy than solids

can be poured - can take shape of its container

can't be compressed

4

what is the arrangement of a gas?

irregular, random arrangement

almost no forces of attractio between the particles

takes shape of its container

particles ofter collide with the walls of its container

particles free to move in any direction - have more energy than particles in liquids and solids

can be compressed

5

what happens when a solid is heated

this is melting

the particles/molecules gain even more kinetic energy which causes them to vibrate faster until they eventually overcome the strong forces existing between them in a solid state

the forces between the particles/molecules get weaker but they are not broken

the particles/molecules still touch but they have no fixed position

6

what happes when a liquid is heated

the particles/molecules gain even more kinetic energy which allows them to overcome the strong forces between them in a liquid state

the molecules seperate, have large speeds and experience weak forces

their motion is rapid and random in nature

their motion causes them to randomly collide with other molecules and their container which exerts a pressure

7

what is the equation for pressure?

pressure = force ÷ area

8

what happens to the motion of particles when they absorb kinetic energy? 

particles vibrate more and more quickly

9

describe what happens to the vibration, kinetic energy and strong forces in a solid when it melts

particles absorb heat and gain kinetic energy

(thermal energy is converted into kinetic energy)

particles vibrate more and more quickly

the strong bonds start to weaken

the solid starts to lose its regular arrangement

10

complete this diagram

(note that solid to liquid red arrow should be going other way)

11

what is the motion of a molecule of gas?

(Brownian motion)

random movement

continuos movement

bump into each other and container

collisions = change indirection or speed of movement

12

how does gas exert pressure on the walls of its container?

pressure is the force acting per unit area

pressure is measured in N/m2

the particles collide together and against their container

when the particles collide they change direction or speed of movement

when particles collide with the walls of their container they exert a tiny force

greater frequency of collisions = greater pressure

13

what is the difference between evaportaing and boiling?

evaportaing can take place at tempratures below the boiling point

boiling takes place throughout the liquid at boiling point

14

what three things does thermal energy do?

it is converted into kinetic energy

it is used to increase the kinetic energy

it is used to break bonds

15

is melting exothermic or endothermic?

endothermic

16

is cooling exothermic or endothermic?

exothermic

17

why does a solid not heat up like x?

thermal energy is being used to break the bonds

18

what state is A and what is happening

solid

particles are vibrating more

19

what state is B and what is happening

melting

strong bonds being broken

20

what state is C and what is happening

liquid

particles are moving about more

21

what state is D and what is happening

boiling

bonds being broken

22

what state is E and what is happening

gas

particles are moving about more

23

what state is A and what is happening

liquid

particles are moving about more

24

what state is B and what is happening

freezing

strong bonds being made

25

what state is C and what is happening

solid

particles moving more

26

what state is D and what is happening

solid

no longer cooling

27

Is there a rise in temperature during a change in state when bonds?

no - even though energy enters or leaves the system

28

Particles in liquids move in ... directions and at ... speeds

Particles in liquids move in random directions and at slow speeds

29

Particles in gases move in ... direction and at ... speeds

Particles in gases move in random directions and at high speeds

30

What is evaporation?

evaporation is when particles escape from a liquid to become gas particles

31

Particles can evaporate from a liquid at temperatures that are muhc higher/lower than the liquid's boiling point

Particles near the surface of a liquid can escape and become gas particles if:

... (2 things)

Particles can evaporate from a liquid at temperatures that are muhc lower than the liquid's boiling point

Particles near the surface of a liquid can escape and become gas particles if:

the particles are travelling in the right direction to escape the liquid

the particles are travelling fast enough (they have enough kinetic energy) to overcome the atractive forces of the other particles in the liquid

32

Which particles (fast or slow) are most likely to evaporate from the liquid?

What does this so to the average speed of the remaining particles and the temperature of the liquid?

The fastest particles (with the most kinetic energy) are most likely to evaporate from the liquid - so when they do, the average speed and kinetic energy of the remaining particles decreases

This decrease in average particle energy means the temperature of the remaining liquid falls - the liquid cools

33

What happens when we excercise or get hot?

you sweat when you exercise or get hot

as the water from the sweat on your skin evaporates, it cools you down