states of matter and seperation techniques - chemistry revision Flashcards
describe the properties of solid (the substance)
- can’t be squashed
- keeps the same volume
- it keeps it’s shape
describe the properties of the particles in a solid
- close together
- in a regular pattern
- they can slide over eachother
describe the properties of liquids (the substance)
- it flows
- can’t be squashed
- it can change shape
- keeps the same volume
describe the properties of the particles in a liquid
- close together
- not in a regular pattern
- they are free to move
describe the properties of gases (the substance)
- it can be squashed into a smaller space
- it flows
- it spreads to fill in the container
describe the properties of the particles in a gas
- not in a regular pattern
- they are widely spread out
what are the names for each of the state changes?
solid to gas - sublimination
gas to solid - deposition
gas to liquid - condensing
liquid to gas - boiling
liquid to solid - freezing
solid to liquid - melting
what happens to the temperature when substances change state?
the temperature stays the same because the energy is being used to break apart the molecules
what happens to particles when the go from solid to liquid to gas?
the particles spread out
what are pure substances?
pure substances have a different melting point (e.g. ice melts at 0℃)
what are impure substances?
impure substances have a range of melting points (ice and water melts from 0-16℃)
what is filtration?
it is used to separate two components of a mixture, one liquid and one insoluble solid
how do you do the process of filtration?
you put the funnel in a beaker, and put filter paper in the funnel, letting the water drip into the beaker, leaving behind the solid
what is evaporation and crystalisation?
used to seperate a solid that is dissolved into a liquid
how do you do the process of evaporation and crystalisation?
as you put the mixture in a bowl and put it over a bunsen burner, evaporating the water and leaving behind the salt that appears as crystals
what is distillation?
it is used to seperate two liquids with different boiling points
how do you do the process of distillation?
you put the mixture into a conical flask with a thermometer in it, then put it over a bunsen burner. the flask is attached with a side arm which takes the steam and gets condensed into liquid in the test tube which is surrounded in ice (to help it go quicker). the thermometer is there to know that when the temperature starts to rise, you remove the test tube, because you have evaporated all of one liquid and our left with the distill
what is chromotography?
it is used to seperate inks
how do you do the process of chromatography?
you put a piece of paper into a test tube with a solvent in it. the piece of paper has a starting line with a dot on it. the line is drawn in pencil so that it doesn’t seperate because it’s insoluble. the solvent has to be below the line.
- if the spot doesn’t move - it is insoluble in the solvent
- if it does move - it is soluble and the more soluble it is, the further up the paper it goes
- if there is only one spot on the paper, it is a pure substance
how do you find the rf value?
distance moved by ÷ distance moved by the solvent
the spot
what is sedimentation?
a process that seperates the liquid from solids that float and that sink
- sometimes alum is added to clump the fine particles together and sink to the bottom
what is chlorination?
it is used to purify water and kill harmful bacteria
how do you do the process of chlorination?
- it’s when you ‘bubble’ chlorine throughout the water to kill pathogens
- purified water is potable (drinkable)
- chlorine is poisonous in large quantities
