Question

What is the heat of mixing when 50 mL of 1 M HCl is added to 50 mL of 1 M NaOH at 25°C assuming no heat loss to the surroundings? Given, the enthalpy of neutralization of 1 M HCl by 1 M NaOH is -55.9 kJ/mol.

Answer 1

To calculate the heat of mixing, we first need to determine the number of moles of HCl and NaOH reacting. Since both solutions have the same concentration and volume, they will react in a 1:1 ratio.Number of moles of HCl =  concentration of HCl    volume of HCl = 1 M  0.050 L = 0.050 molesNumber of moles of NaOH =  concentration of NaOH    volume of NaOH = 1 M  0.050 L = 0.050 molesNow, we can use the enthalpy of neutralization to calculate the heat of mixing.Heat of mixing =  number of moles of HCl    enthalpy of neutralization = 0.050 moles  -55.9 kJ/mol = -2.795 kJThe heat of mixing when 50 mL of 1 M HCl is added to 50 mL of 1 M NaOH at 25C is -2.795 kJ, assuming no heat loss to the surroundings.