Question

Equal volumes, 50.0 mL, of 0.54897 M solution of HCl and 0.9573 M NaOH solutions having an initial
temperature of 18.5 °C react in a coffee-cup calorimeter. OkThe resultant solution records a temperature of
22.9°C. Since the solutions are mostly water, the solutions are assumed to have a density of 1.0 g/mL and a
specific heat of 4.184 J/g °C. The heat capacity of the calorimeter is 1.0 x 10'J/°C.
Calculate the heat gained or released by the solution at constant pressure in J.

Answer 1

Resposta:

Number of moles of HCl and NaOH added

= 1000

MV

= 1/1000×50

=0.05

Mass of mixture =V×d=100×=100g

Heat evolved, q=msΔT=100×4.18×(27.5−21.0)

=100×4.18×6.5J=2717J=2.717 kJ

(b) The involved reaction is:

HCl(aq.)+NaOH(aq.)→NaCl(aq.)+H2O

ΔH= Heat evolved per mol

= 0.05−2.717

=−54.34 kJ