The addition of hydrochloric acid to a silver nitrate solution precipitates silver chloride according to the reaction:

AgNO3 (aq) + HCl (aq) →AgCl (s) + HNO3 (aq)

When 50.0 mL of 0.100 M AgNO3 is combined with 50.0 mL of 0.100 M HCl in a coffee-cup calorimeter, the temperature changes from 23.40 ∘C to 24.21 ∘C.

Calculate ΔHrxn for the reaction as written. Use 1.00 g/mL as the density of the solution and Cs=4.18J / (g⋅∘C) as the specific heat capacity of the solution.

Question

Terrence Mack

Chemistry

26 March, 07:47

The addition of hydrochloric acid to a silver nitrate solution precipitates silver chloride according to the reaction:

AgNO3 (aq) + HCl (aq) →AgCl (s) + HNO3 (aq)

When 50.0 mL of 0.100 M AgNO3 is combined with 50.0 mL of 0.100 M HCl in a coffee-cup calorimeter, the temperature changes from 23.40 ∘C to 24.21 ∘C.

Calculate ΔHrxn for the reaction as written. Use 1.00 g/mL as the density of the solution and Cs=4.18J / (g⋅∘C) as the specific heat capacity of the solution.

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Answers (1)

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Hana · Answer 1

In the given question, T₁ = 23.40 °C, and T₂ = 24.21 °C,

ΔT = T₂-T₁ = 24.21 - 23.40

= 0.81

Total volume of solution = 50 + 50 = 100 ml

Density of solution = 1.0 g/ml

Mass of solution = density * volume = 100 * 1 = 100 gm

q = mcsdT = 100 * 4.184 * 0.81 = 338.9 J

Moles of AgNO₃ = 50 * 0.100 / 1000 = 0.005, similarly moles of HCl is 0.005.

0.005 mol = 338.9 J / 0.005 = 67.78 KJ

ΔHrxn = - 45.8 KJ/mol.