Question

In a coffe cup calorimeter, 50.0mL of 0.100M of AgNO3 and 50mL of 0.100M HCl are mixed to yield the following reaction:

Answer 1

Answer:

The enthalpy change of the reaction is -66.88 kJ/mol.

Explanation:

Mass of the solution = m = 100 g

Heat capacity of the solution = c = 4.18 J/g°C

Initial temperature of the solutions before mixing = $T_1=22.60^oC$

Final temperature of the solution after mixing = $T_2=23.40^oC$

Heat gained by the solution due to heat released by reaction between HCl and silver nitrate = Q

$Q=m\times c\times (T_2-T_1)$

$Q=100 g\times 4.18 J/g^oC\times (23.40^oC-22.60^oC)=334.4 J$

Heat released due to reaction = Q' =-Q = -334.4 J

Moles of silver nitrate = n

Molarity of silver nitrate solution = 0.100 M

Volume of the silver nitrate solution = 50.0 mL = 0.050 L ( 1 mL = 0.001 L)

$Moles =Molarity\times Volume (L)$

$n=0.100 M\times 0.050 L=0.005 mol$

Enthalpy change of the reaction = $\Delta H$

$=\Delta H=\frac{-334.4 J}{0.005 mol}=-66,880 J/mol=-66.88 kJ/mol$

1 J = 0.001 kJ

The enthalpy change of the reaction is -66.88 kJ/mol.