A 100.00 ml of volume of 0.500 M HCl was mixed with 100.00 ml of 0.500 M KOH in a constant pressure calorimeter. The initial temperature of individual acid and base was 23.0 oC. The final temperature after mixing was 25.5 oC. The specific heat of the solution was 3.97 J g-1 oC-1 Assume the density of the solution is 1.00 g mL-1 a) Calculate the heat of the reaction in kJ. (Be sure to use signs correctly.) b) Calculate the enthalpy of the reaction in kJ/mol. (Be sure to use signs correctly.) DO NOT put units in the answer box or your answer will be counted wrong.

The heat of the reaction = - 1985 J = - 1.985 kJ

The enthalpy of the reaction is - 39.7 kJ / mol

Explanation:

Step 1: Data given

Volume of HCl = 100 mL the heat of the reaction = 0.1 L

Molarity of HCl solution = 0.500 M

Volume of KOH = 100 mL = 0.1 L

Molarity of KOH solution = 0.500 M

Initial temperature = 23.0 °C

Final temperature = 25.5 °C

Specific heat of the solution = 3.97 J/°C * g

Density of the solution = 1g / mL

Step 2: Calculate heat

Q = m*c*ΔT

with m = the mass of both solution : 100g + 100 g (since density = 1g/mL) = 200 g

c = the specific heat = 3.97 J/°C*g

ΔT = T2 - T1 = 25.5 = 23 = 2.5 °C

Q = 200g * 3.97 J/°C*g * 2.5°C = 1985 J ( = - 1985 J because it's exothermic)

Step 3: Calculate the number of moles

Number of moles = Molarity * Volume

Number of moles = 0.5 * 0.1 L = 0.05 moles

(Moles of the acid are equal to the moles of water produced.

Moles of solution = 0.05 moles)

Step 4: Calculate the enthalpy of the reaction

ΔH = heat change / Number of moles

= - 1.985 kJ / 0.05 moles

= - 39700 J/mol = - 39.7 kJ / mol

The enthalpy of the reaction is - 39.7 kJ / mol

The enthalpy of the reaction is negative, this means the reaction is exothermic (which means the final temperature is higher than the initial temperature.)