SC1+2 - States of matter Flashcards
describe a solid
close together atoms
regular structure
vibrate around fixed positions
least energy stored
describe a liquid
close together atoms
move around eachother
random pattern
describe a gas
far apart
random pattern
move fast in all directions
most stored energy
what is the state change from a gas to a solid called
desublimation
what type of change is a state change
physical change
what changes during a state change
energy is transferred to or from the particles
arrangement of particles changes
the movement of particles changes
what is an element
a substance that consists of only atoms with the same atomic number
what is a compound
a substance that consists of two or more elements chemically joined together
what is a mixture
contains different elements and/or compounds not chemically joined together
what is the meaning of pure
only contains one element or compound
what type of melting point so pure and un pure substances have ?
pure- sharp melting point
impure- melt over a range of temperatures
what is filtration
seperates an insoluble solid from a liquid or gas
eg: sand and water or peas and water
what is the filtered through liquid called
filtrare
what can crystillisation do
seperates a solvent and solute
why do you crystalise slowly at the end
the particles will have longer to form an ordered pattern and will make larger crystals
what can you use paper chromatography to do
-distinguish between a pure and an impure substance (pure substances produce one dot)
-identify a substance by comparing its spots with those of known substances with an rf value
explain what happens during paper chromotography
The more soluble a compound the faster it travels up the paper The less soluble inks travel slower and therefore seperate
in chromatography what are the mobile phase and stationary phase
mobile- solvent/water
stationary- chromatography paper
what is the equation for rf
distance traveled by spot/distance traveled by solvent
what is simple distillation used for
used to seperate a liquid from solid minerals
what is drinking water called
potable
what must potable water have
low levels of contaminating substances
low levels of microbes
Explain how water is made potable
sedimentation- small insoluble particles sink to the bottom
filtration- insoluble particles are removed by filtering water through bodies of sand and gravel
chlorination- chlorine gas is bubbled through the water to kill microbes which may cause disease
