5.2.2 Enthalpy and entropy

Question 1

what is entropy

Answer 1

the dispersal of energy in a system.
Entropy increases as a system becomes more disordered

Question 2

what leads to entropy becoming more positive

Answer 2

-change of state eg-from solid to liquid OR liquid to gas
-reactions that produce a gas
-increases in the number of moles
-dissolving (solid dissolving in water)
eg-NaCl(s)——->NaCl(aq)

Question 3

what leads to entropy becoming more negative

Answer 3

-change in state (gas to liquid or liquid to solid)
-decrease in the number of moles
-randomness of particles decreases

Question 4

how do you calculate entropy changes

Answer 4

deltaS=products-reactants
-use molar ratio

Question 5

what are entropy units

Answer 5

Jk-1 mol-1

Question 6

are standard entropies positive or negative

Answer 6

positive

Question 7

which has a larger increase in entropy
A) Solid to liquid
b) Liquid to Gas

Answer 7

B) liquid to gas

Question 8

what is Gibbs equation

Answer 8

deltaG=deltaH-TdeltaS

Question 9

what must deltaG be for a reaction to be feasible

Answer 9

deltaG<0

Question 10

units for Gibbs equation

Answer 10

delta S must be divide by 1000
degrees c in K by +273

Question 11

how do you work out the temperature the reaction is feasible

Answer 11

T=deltaH/deltaS