The heat of fusion ΔHf of toluene C6H5CH3 is 6.6 /kJmol . Calculate the change in entropy ΔS when 46.g of toluene melts at −95.0°C

Answer : The entropy change of the toluene is 18.5 J/K

Explanation :

To calculate the number of moles, we use the equation:

Given mass of toluene = 46 g

Molar mass of toluene = 92.14 g/mol

Putting values in above equation, we get:

To calculate the entropy change for different phase at same temperature, we use the equation:

where,  

= Entropy change  = ?

n = moles of toluene = 0.499 moles

= enthalpy of fusion = 6.6 kJ/mol = 6600 J/mol   (Conversion factor:  1 kJ = 1000 J)

T = temperature of the system =

Putting values in above equation, we get:

Hence, the entropy change of the toluene is 18.5 J/K

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.

the answer to your question is c