5.2.2 Enthalpy and entropy

what is entropy

measure of dispersal of energy in a system

what does the greater the entropy mean

the more disordered the system

symbol for entropy

S

symbol for entropy change

ΔS

what happens to entropy as you go solid to liwuid to gas

becomes more disordered

what happens to entropy as you dissolve a solid

increases its entropy

what happens to entropy as there are more gaseous particles

increases

units of entropy change 

JK^-1mol^-1

when will chemical reactons only take place with entropy change

when overall entropy change is positive

entropy change of system equation

ΣSproducts - ΣSreactants

entropy change of surroundings equation 

-enthalpy change/temperature

what is units of enthalpy change in entropy change of surroundings equation 

Joules

what is units of temperature in entropy change of surroundings equation 

K

total entropy change 

entropy change of system + entropy change of surroundings

what happens to entropy as temperature increases

entropy increases

what is free energy change

measure used to predict whether a reaction is feasible

feasible reaction

reaction that once started will carry on to completion without any energy being supplied to it

when is a reaction feasbile 

if free energy change is negative or zero

gibbs / free energy change equation

units of free energy change

Jmol^-1

units of enthalpy change in gibbs equation 

Jmol^-1

why might a reaction not take place even if △G is negative

high activation energy,slow rate of reaction

equation to work out temperature at which reaction is feasible

△H/△S

id a reaction is exothermic and has a positive entropy change what  will △G always be 

negative

id a reaction is endothermic and has a negative entropy change what  will △G always be 

positive

if a reaction is exothermic and has negative entropy change when will it be feasible

low temperature

if a reaction is endothermic and has positive entropy change when will it be feasible

high ttemperatres

gibbs equation in y=mx + c form

△G=-△s T + △H

what is the gradient of straigt line gibbs

-△S

what is the y intercept of straight lien gibbs 

△H