Question

(b) The reaction between an acid and a base produces salt and water. A mixture of

100.0 cm' of 0.431 mol dm HCI solution and 100.0 cm' of 0.216 mol dm Ba(OH)2, solution is
added into a constant-pressure calorimeter. Determine the final temperature of the mixture if the
initial temperature of both solutions is 20.5 °C.
[5]
[Specific heat capacity of water is 4.18 Jg'°C and heat of neutralisation is -56.2 kJ mol-')​

Answer 1

Step-by-step explanation:

The neutralization reaction equation

2 HCl + Ba(OH)2 → Bacl₂ + 2 H₂O

number of mole of HCl = 0.431 × ( 100 / 1000) dm³ = 0.0431 mol

number of mole of Ba(OH)2 = 0.216 × ( 100 / 1000) dm³ = 0.0216 mole

comparing their stoichometry mole ratio

2 HCl react with 1 mole of Ba(OH)₂ TO yield 2 mole of water

0.0431 will react with 0.0216 mole to yield 0.0431 mole of water

H⁺ + OH⁻ → H₂O

q ( quantity of heat ) = heat of neutralization × number of mole of water = - 0.0431× -56.2 kJmol⁻¹= -2.42784 KJ

q = mc ( T₂ - T₁)

q / mc = T₂ - T₁

T₂ = (q / mc) + T₁ = ( 2427.84 J / ( 200 g × 4.184) + 20.5 °C = 23.401°C