Entropy and free energy

• What is entropy

  The amount of extra energy of motion that is added per mole of substance for each degree the temperature rises
• so entropy is a measure of …

  the amount of disorder
• what is the symbol of entropy

  S theter
• what are the units of entropy

  JK-1Mol-1
• entropy can be used to explain..

  the arraignment of particles in a substance
• why does ice melt in regard to entropy

  H2O (s) —> H2O (l)

  an increase in entropy as the state changes from solid to liquid
• what does salt dissolve in water in regard to entropy

  NACl (s) —> Na+ (aq) + Cl- ( aq)

  an increase in entropy as the state changes from solid to aqueous
• why does butane burn readily in oxygen

  7 1/2 C4H10 (g) + 2 O2 (g) —> 2 CO2 (g) + 5 H20 (g)

  increase amount of energy as the amount of moles has increased
• what is the formula to calculate the change in standard entropy

  change in entropy = products - reactants
• what does a negative value of entropy suggest

  that there is a decrease of disorder
• what does a positive entropy suggest

  that the amount of disorder will increase
• when is a reaction likely to take place to do with entropy

  more likely to take place if entropy change is positive because the amount of disorder increases
• what is free energy

  weather a reaction in feasible or not
• what is the free energy calculation 


  change in g = change of h ( enthalpy ) - T x change in s ( entropy )
• if delta g is bigger than 0 what does that mean

  the reaction is feasible
• if delta g is less than 0 what does that mean

  the reaction is not feasible
• what does it mean id change of g is equal to 0

  it is where the reaction begins to take place
• When using free energy calculation in an exam what do you have to show

  The rearranged formula E.g

  
• What do you look at to Determine a change in entropy

  An change in states or a change in moles