solids, liquids and gases

Question 1

equation

Answer 1

density = mass/volume

Question 2

density

Answer 2

• density is the mass peer unit volume of a substance- dense materials have particles close together

Question 3

pressure

Answer 3

p=f/a
p=pressure
f=force
a=area
1 pascal= 1N/M squared

Question 4

pressure in water

Answer 4

pressure= density of fluid * gravity* vertical depth
p=rgh
r= greek rho

Question 5

changes of state

Answer 5

gas to solid - reverse sublimation
solid to gas- sublimation
solid to liquid - melting
liquid to solid- freezing
liquid to gas- evaporation
 gas to liquid- condensation

Question 6

pressure (balloon)

Answer 6

when fast moving particles of a gas hit the walls of their container they exert a pressure e.g. balloonyou get a bigger pressure if:

1) the particles hit the walls faster(you heat up the gas)
2) more particle hit the walls each second(add more gas)gas pressure measured in pascals(pa)

Question 7

The absolute temperature

Answer 7

absolute 0 is the coldest possible temperature . at this temperature the particles of gas are completely motionless(pressure 0) and take up no volume
absolute zero = -273 degrees C = 0 kelvin
- water freezes at 273 k-
water boils at 373k

Question 8

how do we know gas particles are moving?

Answer 8

-gases will quickly move in a vacuum-
gas pressure- the moving particles create a pressure-
smells can diffuse- the gas particles move around the room-
Brownian motion: -invisible air molecules jostle the smoke particles. the smoke can be seen to move randomly under a microscope

Question 9

boyle’s law

Answer 9

• the gas exerts pressure
• push in the piston to halve the volume
• the particles of gas move around in half the volume so they hit the walls of the piston twice as many times. the pressure doubles
• pressure is inversely proportional to volume:
  P is proportional to 1/V boyle’s law or P1V2= P1V2p= pressure V= volume
  1= starting value
  2= final value
  boyle’s law applies if the temp is constant and the mass of the gas is constant