Question

50.0 mL of 1.25M HCl is mixed with 30.0mL of 1.0M Sr(0h)2 to form a solution.The temperature of the solution rises from 22.10 degrees Celsius to 31.32 degrees Celsius. The specific heat capacity of the solution is 4.18 j/g C. Calculate the energy in kj for the solution process. Label your kj as endo or exothermic.

Answer 1

Sr(OH)2 + 2HCl -------------> SrCl2 + 2H2O

1 mole     2 moles

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

                                      = 1*0.03   = 0.03 moles

no of moles of HCl         = molarity * volume in L

                                      = 1.25*0.05 = 0.0625 moles

1 moles of Sr(OH)2 react with 2 moles of HCl

0.03 moles of Sr(OH)2 react with = 2*0.03 = 0.06 moles of HCl

    limiting reactant is Sr(OH)2

1 moles of sr(OH)2 gives 2 moles of H2O

0.03 moles of Sr(OH)2 gives = 2*0.03 = 0.06 moles of H2O

mass of solution = volume * density

                           = 80*1 = 80g/ml

q = mCT

    = 80*4.18*(31.32-22.1)   = 3083.17J

     = 3083.17/0.06    = 51.4KJ/mole