kpt Flashcards
def matter
a substance that has mass and occupies space
two factors that can change state of matter
temperature + pressure
what does the kinetic particle theory state
states that all matter is made up of tiny discrete particles and that these particles are in constant random motion
why does solid have a fixed shape
- held together by very strong forces of attraction
- has enough ke to only vibrate and rotate about their fixed positions
- cannot move freely
why does liquid not have a fixed shape
- have weaker forces of attraction than particles of a solid
- have more ke than particles of the same substance in solid state and are not held in fixed position; move by sliding over each other
- can move freely throughout the liquid
why does gas not have a fixed shape
- have weaker forces of attraction than liquid
- has a lot more ke and are not held in fixed positions
- can move rapidly in any direction
why does two gases in a jar form a uniform colour after some time
this is because the gases are made up of tiny particles moving in constant random motion. gas 1 particles diffuse from the lower jar into the spaces of gas 2 particles in the upper jar. at the same time, gas 2 particles diffuse down from the upper jar to mix with the gas 1 particles in the lower jar. after some time, the gas 1 and gas 2 particles have diffused throughout the 2 jars to give a uniform brown colour
why is there a need to put the denser gas at the bottom of the jar in an experiment to show diffusion
cannot put the denser one on top as it might come down due to gravity, making it difficult to prove if particles came down due to gravity or diffusion
how does temp affect diffusion
as matter is heated, temperature increases and the particles of matter gain more energy, causing them to move faster and thus increasing the rate of diffusion → the higher the temperature, the faster the rate of diffusion
how does relative molecular mass affect diffusion
the greater the rmm, the slower the molecules diffuse
how does a porous pot work
using nitrogen outside pot and co2 inside pot
the nitrogen (14) has a lower rmm compared to co2 (44), therefore it will diffuse into the porous pot faster than the co2 can diffuse out. pressure will build up in the porous pot and the water level beneath the pot will be pushed down. after some time, the water will go back to the initial level
movement of states
liquid →mobile and able to move freely throughout the liquid by sliding over one another
solid → able to vibrate and rotate about a fixed position but cannot move throughout the solid
gas → constantly moving rapidly and in random directions
describe the process of melting
as solid is heated, temperature increase so the particles gain energy and vibrate faster about their fixed position
as temperature continues to increase, the particles are able to overcome the forces of attraction that hold them in their fixed positions and melts
upon melting, the particles are no longer in their fixed positions and can move freely throughout the liquid
true of false: heat energy is given out during melting
false. heat energy is taken in
why does temperature not change during melting
substance uses heat energy to overcome its forces of attraction instead of using it to increase the temperature
describe freezing + why temp doesnt change during freezing
temperature doesn’t change during freezing → heat energy given out to surroundings is compensated completely by the energy released as liquid particles form stronger forces of attraction
as particles of liquid are cooled, they lose kinetic energy and begin to move more slowly
when the temperature is low enough, the particles no longer have enough energy to move freely and start to settle into fixed positions
finally, all the particles settled into fixed positions
is heat given in or out during freezing
given out
describe process of boiling + why temp stays the same during boiling
during boiling, particles have enough energy to break all the forces of attraction
temp remains constant during boiling as heat energy is absorbed to break all the forces of attraction holding the particles of the liquid together instead of increasing the temperature
pure substances has a fixed boiling point only at a fixed pressure
does increase in pressure cause a increase/decrease in boiling point
increase
is heat energy given in or taken out during boiling
taken in
def evaporation
the process in which a liquid changes into a gas at temperatures lower than its boiling point
how does evaporation occur
some particles have enough energy to escape as a gas
difference between evaporation and boiling
boiling:
occurs only at bp
occurs throughout the liquid
occurs rapidly
evaporation
occurs at temperatures below bp
occurs only at the surface of the liquid
occurs slowly
does condensation take in or give out heat
given out
how does condensation occur
heat energy energy is given out by gas particles during condensation
def sublimation
the process in which a solid changes directly into a gas without passing through the liquid state
when does sublimation occur
particles at the surface of the solid have enough energy to break away from the solid as a gas
how to use kpt to describe change in state
1) identify key temperature involved eg starting temp/mp/bp/ending temp
2) state initial state of substance
3) describe arrangement (proximity and orderliness)
4) describe movement of particles
5) state whether particles gain/lose energy and describe what happens
6) state change of state occurring during eg melting
7) state the new state at the given temperature
8) describe the new arrangement and movement of particles in the new state
