12A.3

Question 1

when gas is formed from Liquid and Solid what will the total entropy be

Answer 1

positive

Question 2

if the total entropy is positive the reaction is

Answer 2

thermodynamically spontaneous

Question 3

what happens when an ionic solid dissolves

Answer 3

1. the lattice structure is broken down
2. the ions are hydrated

Question 4

the breakdown of a lattice structure is a

Answer 4

endothermic process

Question 5

how does the breakdown of lattice structure increase the entropy

Answer 5

even though it’s an endothermic process, the number of moles of the particles increases when the ions are separated so more arrangements so more entropy

Question 6

the hydration of ions is a

Answer 6

exothermic process

Question 7

how does the hydration of ions decrease the entropy

Answer 7

even though it is an exothermic process, the hydration of the ions causes the water molecules to become more order as they arrange them selfs around the negative and positive ions causing less disorder so less entropy

Question 8

the ordering of water molecules (during hydration) is significant when dissolving

Answer 8

Anhydrous salts

Question 9

the solubility of a solid depends on 3 factors, what are they

Answer 9

1. the change of entropy in the system
2. the value of H solution (change in)
3. T

Question 10

if the S total of a solid is negative it will be (when reacting with water)

Answer 10

insoluble

Question 11

if the S total of a solid is positive it will be (when reacting with water)

Answer 11

soluble

Question 12

If you increase the number of moles the number of particles will

Answer 12

increase

Question 13

what will happen to S total if the number of moles in the product is more than the number of moles in the reactant

Answer 13

it will increase since more moles mean more particles which means more arrangments which means more entropy

Question 14

solubility of a metal hydroxide increases

Answer 14

down the group

Question 15

solubility of a metal sulfate increase

Answer 15

up the group

Question 16

why does the solubility increase down the group for metal hydroxides

Answer 16

Because as you go down the group the value of change in solution enthalpy becomes more negative giving us a larger value for change in entropy of surroundings, and the entropies of cations become more positive down the group which favors solubility

Question 17

why are the standard entropies of the hydroxide ion left out of the explanation of the trends in MOH

Answer 17

because the ion is common to all metal metal hydroxides

Question 18

the trend in the entropies of the hydrated cations mirrors the

Answer 18

the trend in the S system (change in)

Question 19

why are the standard entropies of the sulfate ion left out of the explanation of the trends in MSO4

Answer 19

because the ion is common amongst all the other MSO4

Question 20

why are metal sulfates more soluble up the group

Answer 20

as you go up the group the change in the enthalpy of the solution becomes more negative causing the entropy change of the surrounding to be greater, and even though as you go up the group the change of entropy of the hydrated cation increases the change in the entropy of the surrounding would be further greater making it more soluble