States of Matter Flashcards
Solids
- strong forces of attraction between particles, which holds them close together in fixed positions to form a regular lattice arrangement
- particles DONT MOVE but vibrate about their positions… the hotter the solids become the more they vibrate , causing them to expand slightly when heated
liquids
- weak force of attractions between the particles.
- they’re randomly arranged
- and free to move but usually stick close together
- definite volume but not a definite shape
- particles constantly moving randomly. the hotter the liquids get the faster they move = expand when heated
gases
- forces of attraction between particles is very weak - particles travel in straight lines
- don’t keep a definite shape or volume
- move constantly with random motion
- hotter the gas faster it moves
solvent
the LIQUID it’s dissolving into
solute
the substance being dissolved
solution
a mixture of a solute and solvent
saturated solution
a solution where the maximum amount of solute has been dissolved so no more solute will dissolve
solubility
a measure of how much solute will dissolve in a solvent. often measured in grams of solvent per 100g of solvent
solubility of a solid practical
- saturated solution
- stir and place in water bath at 25°c
- after 5 mins check all excess has fallen to bottom and check temp has reached 25
- weigh an empty evaporating basin. pour some of the solution into basin
- reweigh basin and contents and gently heat using a bunsen burner to remove all water
- once all water has evaporated you’re left with pure ammonium chloride
- reweigh evaporating basin and contents
- repeat twice more at different temps
- use masses to work out solubility
solubility equation
solubility = mass of solid (g) / mass of water removed x100
atom
made up of protons neutrons and electrons
atomic number
how many PROTONS there are
mass number
number of protons and neutrons
molecules
groups of atoms
compounds
a substance made of 2 or more different elements that are chemically bonded together.
difficult to separate, properties completely different to original elements.
mixtures
- easy to separate
- no chemical bonds.
- not a pure substance (boil or melt over a ranges of temps )
pure substance
= fixed melting and boiling point
simple distillation
separate a liquid from a solution. eg. pure water from seawater.
- solution is heated, part with lowest boiling point evaporates
- vapour is cooled and condenses and is collected
- rest of solution left behind.
fractional distillation
separate a mixture of liquids
- put mixture in flask with fractionating column on top, heat it
- different liquids = different boiling points = evaporate at different temps
- liquid with lowest boiling point evaporates first. reaches top of column and is collected. raise temp and next is collected
filtration
separate an insoluble solid from a liquid
crystallisation
separate a soluble solid from a solution
- pour into evaporating dish. gently heat. some water evaporates and solution more concentrated
- remove from heat and leave to cool
- leave in a warm place and crystals will form.
paper chromatography
- draw a pencil line near bottom of a sheet of filter paper
- add spots of different inks to the line at regular intervals
- place in a beaker of solvent (water) with level of solvent below the baseline
- place a lid to stop the solvent evaporating
- the solvent seeps up the paper carrying the inks with it
- each different dye in the inks will move up the paper at a different rate and form a spot in a different place
- when solvent nearly reached the top take paper out of beaker and leave to dry = chromatogram
how to calculate Rf value
Rf = distance travelled by solute / distance travelled by solvent
