Question

In a constant-pressure calorimeter, 60.0 mL of 0.330 M Ba(OH)2 was added to 60.0 mL of 0.660 M HCl. The reaction caused the temperature of the solution to rise from 21.42 °C to 25.92 °C. If the solution has the same density and specific heat as water (1.00 g/mL and 4.184 J/g·°C, respectively), what is ΔH for this reaction (per mole of H2O produced)? Assume that the total volume is the sum of the individual volumes.

Answer 1

total volume   = 60 + 60 = 120ml

mass of solution   = volume * density

                              = 120*1 = 120g

   q   = mcT

         = 120*4.184*(25.92-21.42)   = 2259.36J

Ba(OH)2 + 2HCl ------------------> BaCl2 + 2H2O

no of moles of Ba(OH)2 = molarity*volume in L

                                        = 0.33*0.06   = 0.0198moles

no of moles of HCl    = molarity*volume in L

                                 = 0.66*0.06   = 0.0396 moles

2 moles of Hcl produce 2 moles of H2O

0.0396 moles of HCl produce 0.0396 moles of H2O

heat energy released = -2259.36/0.0396 = -57054J/mole   =- 57.054KJ/mole >>>>answer