A20 wt% a solution is obtained by mixing a component with b in an insulated mixer at steady state. for every mole of solution 1 kj is removed to keep the system temperature constant. determine the enthalpy of mixture for this solution. molecular weight of a: 100 g/mol; molar enthalpy of pure a: 10 kj/mol molecular weight of b: 50 g/mol; molar enthalpy of pure b: 6 kj/mol

Answer : The enthalpy of mixture for this solution is, 5.4 kJ/mol

Explanation :

As we are given that 20 wt% of A solution. That means,

In 100 g of solution, there 20 g of A and 80 g of B.

Now we have to calculate the moles of A and B.

Now we have to calculate the total number of moles of solution.

Total number of moles of solution = Moles of A + Moles of B

Total number of moles of solution = 0.2 + 1.6

Total number of moles of solution = 1.8 mole

Now we have to calculate the amount of energy removed.

As, 1 mole of solution released energy = 1 kJ

So, 1.8 moles of solution released energy = 1.8 × 1 kJ = 1.8 kJ

Now we have to calculate the enthalpy of mixing of A and B.

Now we have to calculate the actual enthalpy of mixing of solution.

Actual enthalpy of mixing of solution = 11.6 - 1.8 = 9.8 kJ

Now we have to calculate the enthalpy of mixture in kJ/mol.

Enthalpy of mixture =

Therefore, the enthalpy of mixture for this solution is, 5.4 kJ/mol