a2 chemistry- entropy and gibb's free energy

system

experiment or reaction which is involved in the investigation

surrounding

container which is involved in the experiment

spontaneous change

reaction takes place on its own without taking any external energy
can be slow, moderate or fast

rusting of iron

slow

combustion

fast - provided with one time o2

free radical reaction in methane

fast - sunlight is needed to start the reaction

evaporation of water at rtp

slow

hydrolysis of ester

moderate

entropy

is represented by snod (standard condition, 1 atm, 298k)
entropy=energy which is measured in jolmol-1kj-1
calorimeter is used to measure energy
dispersal of energy from system to surrounding and surrounding to system, so disorderness increases is called entropy

states and entropy- solid

particles are tightly packed together
regular arrangement of particles
negligible random motion
solids have less entropy values

diamond and graphite have

lower entropy values

caco3

entropy value=+91, higher than ca and caf2

caco3 structure

complicated structure
ionic+covalent bonding

more complicated the structure

higher the entropy value

entropy value is always

positive

resonance is

charge oscillation--->complicated structure
(charge oscillation is resonate)