entropy

Question 1

deltaS system =

Answer 1

products - reactants

Question 2

deltaS surroundings =

Answer 2

• deltaH (Jmol -1) divided by T (K)

Question 3

deltaS total =

Answer 3

system + surroundings

Question 4

how to know if the reaction is feasible

Answer 4

if deltaS total is over 0

Question 5

what factors affect entropy (in order of importance)

Answer 5

1 phase
2 no. moles
3 complexity

Question 6

order of increasing entropy phase

Answer 6

solid, liquid, gas

Question 7

how does no. moles affect entropy

Answer 7

more moles, higher entropy

Question 8

how does complexity affect entropy

Answer 8

more complex, higher entropy

Question 9

define entropy

Answer 9

a property of matter that is associated with the degree of randomness/ disorder of the particles

Question 10

what is the first law of thermodynamics

Answer 10

energy cannot be created or destroyed. It can be transferred from one place to another and in that transfer can be made to do work.

Question 11

what is the third law of thermodynamics

Answer 11

the entropy of a perfect crystalline substance at 0 K is zero. (impossible to achieve)

Question 12

what is the standard molar entropy (S)

Answer 12

the entropy per mole of a substance under standard conditions, usually 298K and 1atm.

Question 13

what is the units for standard molar entropy

Answer 13

J mol -1 K -1

Question 14

what is the value of deltaS surroundings for exothermic reactions

Answer 14

positive

Question 15

what is the value of deltaS surroundings for endothermic reactions

Answer 15

negative

Question 16

second law of thermodynamics

Answer 16

every natural thermodynamic process proceeds in the direction in which the total entropy is increased

Question 17

when will the reaction be spontaneous

Answer 17

if deltaS total is greater than 0

Question 18

how to figure out at what temperature the reaction becomes feasible

Answer 18

T (in K) = deltaH divided by deltaS system

Question 19

what is the requirement for equilibrium

Answer 19

deltaS total = 0

Question 20

define melting point

Answer 20

the temperature at which both the liquid and the solid phases are in equilibrium

Question 21

define activation energy

Answer 21

the minimum energy for a reaction to occur

Question 22

Gibbs energy (deltaG) =

Answer 22

entropy (deltaH) - (temperature x entropy of reaction (TdeltaS))

Question 23

how toes Gibbs energy relate to feasibility

Answer 23

reaction is feasible when Gibbs energy is negative