physics paper 2 - solids liquids and gases

Question 1

density=

Answer 1

mass/volume

Question 2

density is measured in?

Answer 2

g/cm^3 or kg/m^3 1g/cm^3 = 1000kg/m^3

Question 3

what does the average density of an abject determine?

Answer 3

whether it floats or sinks

Question 4

how will a solid object float?

Answer 4

if it has a lower density than the fluid

Question 5

how come you measure the volume of an oddly shaped solid?

Answer 5

completely immersing it in a measuring container of water- the volume difference- only works for objects denser than water

Question 6

pressure=

Answer 6

force/area

Question 7

pressure is measured in?

Answer 7

pascals =Pa

Question 8

the same force applied over a larger area creates?

Answer 8

a lower rpessure

Question 9

in gases and liquids at rest, how does the pressure act on all points?

Answer 9

equally in all directions

Question 10

in gases and liquids how does the pressure increase?

Answer 10

with depth

Question 11

pressure difference is the?

Answer 11

the pressure between two points in a liquid or gas

Question 12

pressure difference=

Answer 12

height x density x g

Question 13

1m^3=

Answer 13

1000 000 cm^3

Question 14

what does particle theory say?

Answer 14

that gases consist of very small particles which are constantly moving in completely random directions. the particles hardly take up any space
they constantly collide with each other and with the walls of their container
if you increase the temperature of the gas you give its particles more energy

Question 15

what happens as you heat up a gas?

Answer 15

the average speed of its particles increases- has kinetic energy

Question 16

what is brownian motion?

Answer 16

the zig-zag random motion of particles in a liquid

large heavy particles can be moved with Brownian motion by smaller, lighter particles travelling at high speeds

Question 17

what is absolute zero

Answer 17

the coldest anything can get =-273 degrees- atoms have as little KE as possible
it’s the start of the kelvin scale -273 degrees= 0Kelvin

Question 18

to convert degrees celcius to kelvins

Answer 18

add 273

Question 19

to convert kelvins to degrees celcius

Answer 19

subtract 273

Question 20

how do particles create pressure?

Answer 20

when they collide with something, they exert a force on it and their momentum and direction change. In a sealed container gas particle smash against the container’s walls-creating an outward pressure- depends on how fast the particles are going and how often they hit the walls

Question 21

how does heating a gas increase the pressure?

Answer 21

the particles move faster and have more KE so hit container’s walls harder and more often creating more pressure- temp in K and pressure are proportional- Double the temp= double the pressure

Question 22

same amount of gas in bigger container?

Answer 22

pressure will decrease as fewer collisions between the gas particles and the container’s walls

Question 23

pressure x volume =

Answer 23

constant

Question 24

at a constant temp what is the pressure?

Answer 24

p1V1=p2V2

Question 25

how are solids held together?

Answer 25

strong forces of attraction hold the particles close together in a fixed, regular arrangement. the particles don’t have much energy so they can only vibrate about their fixed positions

Question 26

how are liquids in their state?

Answer 26

weaker forces of attraction between the particles. they are close together but can pass each other and form irregular arrangements. they have more energy than those in a solid. move in random directions at low speeds

Question 27

how are gases in their state?

Answer 27

almost no forces of attraction between the particles. the particles have more energy than those in liquids and solids- free to move and travel in straight lines in random directions at high speeds

Question 28

what is evaporation?

Answer 28

when particles escape from a liquid and become gas particles. particles can evaporate from a liquid at temperatures that are much lower than the liquid’s boiling point

Question 29

when can particles near the surface of a liquid escape?

Answer 29

1) the particles are travelling in the right direction

2) the particles are travelling fast enough to overcome the attractive forces of the other particles in the liquid

Question 30

what happens to the particles in the liquid when the fastest particles evaporate?

Answer 30

the average speed and KE of the remaining particles decreases

Question 31

what does the decrease in average particle energy mean?

Answer 31

the temperature of the remaining liquid falls and the liquid cools

Question 32

what happens if you double the temperature in kelvins?

Answer 32

the average kinetic energy of the particles double- the temperature of a gas in K is proportional to the average kinetic energy of its particles

Question 33

what is the equation linking pressure and temperature? in a sealed container

Answer 33

pressure/ temperature (in K) = constant
so
p1/T1= p2/T2