solid, liquid, gaseous states of matter o inter-conversion (kinetic particle theory) + energy changes involved
movement of particles in liquid + gases
apparatus for collection + drying of gases
states that all matter is made up of tiny particles that are in constant, random motion
Solid Liquid Gas
Shape
Volume
Compressibility
Arrangement of particles
Forces between particles
Movement of particles
Energy of particles
Density
fixed fixed cannot be compressed packed closely together in orderly arrangement very strong attractive forces between particles particles vibrate + rotate about fixed positions (cannot move freely) not fixed not fixed fixed cannot be compressed close together in a disorderly arrangement strong attractive forces between particles particles slide over each other
(move freely throughout the liquid) not fixed can be compressed
(large space between particles  particles of gas can be forced to move closer together) very far apart in a random arrangement very weak attractive forces between particles particles move about at great speeds (rapidly in any direction) less kinetic energy -----------------------------------------------> more kinetic energy high
(particles close together) high
(particles close together) low
(particles are far apart)

solid heated  particles gain kinetic energy (heat energy converted to kinetic energy)  vibrate more vigorously (within fixed positions)
temp increases  particles vibrate faster  energy gained able to overcome the intermolecular forces holding them in their fixed positions o particles can slide over one another
solid changes to a liquid
solid  liquid
liquid  solid
liquid cooled  particles lose kinetic energy  move slower
temp continues to drop  particles lose more energy  not enough energy to move about freely o particles will settle into fixed positions o particles can now only vibrate about their fixed positions
liquid changes to solid

liquid  gas
heat energy absorbed by particles in liquid
 heat energy converted into kinetic energy
temp rises  particles start to move faster
particles eventually have enough energy to overcome forces of attraction holding them together o particles spread far apart o move rapidly in all directions
liquid  gas
occurs at fixed temp
quick process
takes place within liquid
bubbling occurs
temp remains constant
heat supplied by energy source
heat energy absorbed by particles in liquid  heat energy converted into kinetic energy
temp rises  particles start to move faster
particles eventually have enough energy to overcome forces of attraction holding them together o particles spread far apart o move rapidly in all directions
liquid  gas
occurs at any temp (below b.p.)
slow process
takes place only on the surface
no bubbling occurs
temp may change
heat supplied by surroundings
gas  liquid
gas  liquid
water vapour touches cold surface
condensation occurs  liquid water obtained o heat energy given out during condensation o temp drops  gas particles lose energy  more more slowly  movement slow enough for gas to change into liquid
process by which solid changes directly into gas w/o passing through liquid state
particles at surface of solid have enough energy to break away from solid  escape as gas
e.g.: o iodine, ammonium chloride, dry ice (dry carbon dioxide)

iodine vapour changes back into solid by process of
cold surface absorbs heat from iodine molcules  lose kinetic energy  move about more slowly
strong forces of attraction formed  pull iodine molecules together into fixed positions  solid
net movement of particles (atoms, ions, molecules) from region of higher concentration  lower concentration o i.e. down concentration gradient o e.g. smell of opened bottle of perfume throughout entire room after some time
 tiny gas particles escape from surface of perfume  move at random into spaces between air particles  eventually spread throughout entire room o particles move freely to fill up any available space = diffusion
Temperature
Molecular Mass
(M r
) increase in temp (increase in energy)  increases rate of diffusion molecules with lower molecular masses
(lighter)  diffuse faster than those with higher molecular masses (heavier)

Concentration gradient
Thickness of
Barrier concentration gradient becomes steeper  rate of diffusion increases thickness of barrier increases  rate of diffusion decreases
Diffusion in Gases
gas jar filled with brown bromine gas at bottom + air at top (separated by glass plate)
after removing glass plate for some time  brown bromine gas spread uniformly throughout gas jar  forms homogenous mixture of bromine + air
bromine gas molecules move randomly via process of diffusion to spread throughout jar
Effect of Molecular Mass on Rate of Diffusion
sealed glass tube contains cotton wool moisted w/ aqueous ammonia on one end + cotton wool moistened w/ concentrated HCl acid on other end
molecules of HCl gas + NH
3
gas diffuse into tube  meet to produce white solid NH
4
Cl
gases do not meet in middle o heavier HCl molecules diffuse less rapidly than lighter NH
3
molecules o rather, meet closer to HCl end of glass tube

Collection of gases depends on physical properties: o solubility  how soluble gas is in water o density  how dense gas is compared to air
Downward Delivery
ammonia hydrogen chloride sulfur dioxide chlorine oxygen carbon dioxide hydrogen
extremely soluble very soluble ver soluble soluble very slightly soluble slightly soluble not soluble
less dense denser denser denser slightly denser denser less dense
gas is more dense than air chlorine hydrogen chloride sulfur dioxide
Upward Delivery gas is more soluble in water gas is less dense than air
Delivery over water (Displacement)
gas syringe used to measure the volume of a gas o gas is pushed in fully to expel any gas in syringe o gas from external source enters syringe  pushes plunger outwards gas is insoluble / slightly soluble in water gas is less dense than water ammonia gas hydrogen oxygen methane carbon dioxide

gas can be dried by passing it through a drying agent (to remove water vapour) o concentrated sulfuric acid o quicklime (calcium oxide) o fused calcium chloride using concentrated sulfuric acid used to dry most gases (incl. chlorine, hydrogen chlorine) cannot be used to dry ammonia gas
(reacts with ammonia) using quicklime (calcium oxide) used to dry ammonia gas by placing it on top of the gas
(quicklime = basic/alkaline) cannot be used to dry acids using fused calcium chloride fused calcium chloride
= previously heated calcium chloride can collect all gases but ammonia