Ethanol melts at -114 degree c. the enthalpy of fusion
is5.02kj/mol. the specific heat of solid and liquid ethanol are
0.97jk/g-k and 2.31 j/g-k, respectively. how much heat(kj) is
needed toconvert 25.0 g of solid ethanol at -135 degree c to liquid
ethanolat -50 degree c?

The heat required is 6.88 kJ.

Explanation:

The conversions involved in this process are :

Now we have to calculate the enthalpy change.

where,

= enthalpy change = ?

m = mass of ethanol = 25.0 g

= specific heat of solid ethanol= 0.97 J/gK

= specific heat of liquid ethanol = 2.31 J/gK

n = number of moles of ethanol =

= enthalpy change for fusion = 5.02 KJ/mole = 5020 J/mole

= change in temperature

The value of change in temperature always same in Kelvin and degree Celsius.

Now put all the given values in the above expression, we get

    (1 KJ = 1000 J)

Therefore, the heat required is 6.88 kJ