The molar heats of fusion and vaporization of ethanol are 7.61 and 26.0 kj/mol, respectively. calculate the molar entropy changes for the solid-liquid and liquid-vapor transitions for ethanol. at 1 atm pressure, ethanol melts at −117.3â°c and boils at 78.3â°c.

ΔS= 0.0194 KJ/K.mol

ΔS= 0.074 KJ/K.mol

Explanation:

 Heat of fusion

   Heat required to convert solid state of substance in to liquid state is know as heat of fusion.The temperature remains same during conversion of states .

 Heat of vaporization:

 The heat required to  convert liquid state of substance in to vapor state is know as heat of vaporization.The pressure remains same during conversion of states .

We know that

Entropy change

ΔS= Q /T

Molar entropy changes for the solid-liquid:

 ΔS= Q /T

ΔS= 7.61 /(273+117.3) KJ/K.mol

ΔS= 0.0194 KJ/K.mol

Molar entropy changes for the liquid-vapor:

ΔS= 26/(273+78.3) KJ/K.mol

ΔS= 0.074 KJ/K.mol

no, the red giant is the hottest with 2.00.000.000 degrees celsius. while the white dwarf only 25,000 degrees celsius.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.