Can somebody please help me out? I don\'t understand at all A quantity of 5.10x1
ID: 876185 • Letter: C
Question
Can somebody please help me out? I don't understand at all
A quantity of 5.10x102 mL of 0.60 M HNO3 is mixed with 5.10x102 mL of 0.30 M Ba(OH)2 in a constant-pressure calorimeter of negligible heat capacity. The initial temperature of both solutions is the same at 18.46 C degrees. The heat of neutralization when 1.00 mol of HNO3 reacts with 0.500 mol Ba(OH)2 is -56.2 kJ/mol. Assume that the densities and specific heats of the solution are the same as for water (1.00 g/mL and 4.184 J/g*C degrees, respectively). What is the final temperature of the solution?
Explanation / Answer
we know that
moles = molarity x volume (L)
so
moles of HN03 = 0.6 x 0.51
moles of HN03 = 0.306
also
moles of Ba(OH)2 = 0.3 x 0.51
moles of Ba(OH)2 = 0.153
now
the reaction is given as
Ba(OH)2 + 2HCl ---> BaCl2 + 2H20
so
1 moles of HCl reacts with 0.5 mole of Ba(OH)2
similarly
0.306 moles of HCl reacts with 0.153 moles of Ba(OH)2
now
heat evolved = heat of neutralization per mole of HN03 x moles of HN03
so
heat evolved = 56.2 x 0.306
heat evolved = 17.1972 kJ
now
total volume = 510 + 510
total volume = 1020 ml
given
density = 1 g/ml
so
mass = density x volume
mass of solution = 1 x 1020
mass of solution = 1020 g
now
we know that
heat = mass x specific heat x temp change
so
17.1972 x 1000 = 1020 x 4.184 x dT
dT = 4.03
so
final temp = initial temp + temp change
fianl temp = 18.46 + 4.03
final temp = 22.49
so
the final temperature of the solution is 22.49 C