Question

Calculate the energy (in kJ) required to heat 10.1 g of liquid water from 55 oC to 100 oC and change it to steam at 100 oC. The specific heat capacity of liquid water is 4.18 J/goC, and the molar heat of vaporization of water is 40.6 kJ/mol.

Answer 1

Answer:

           $\large\boxed{\large\boxed{24.6kJ}}$

Explanation:

1. Energy to heat the liquid water from 55ºC to 100ºC

     $Q=m\times C\times \Delta T$

• m = 10.1g

• C = 4.18g/JºC

• ΔT = 100ºC - 55ºC = 45ºC

     $Q=10.1g\times 4.18J/g\ºC\times 45\ºC=1,899.81J$

2. Energy to change the liquid to steam at 100ºC

      $L=\lambda \times n$

• λ = 40.6kJ/mol

• n = 10.1g / 18.015g/mol = 0.5606mol

      $L=40.6kJ/mol\times 0.5604mol=22.76214kJ=22,762.14J$

3. Total energy

       $1,899.81J+22,762.14J=24,661.95J\approx24,662J\approx24.6kJ$