Assisstance with Energy Questions (1 Viewer)

[Dragonmaster262]

When 25 ml 0.20 mol/L sodium hydroxide solution at 23.2 degrees Celsius was added to excess hydrochloric acid present in 50 ml of solution at the same temperature in a light plastic beaker, the temperature of the mixture rose to 24.1 degrees Celsius. Calculate the heat released and hence the enthalpy change.

 

[brenton1987]

When 25 ml 0.20 mol/L sodium hydroxide solution at 23.2 degrees Celsius was added to excess hydrochloric acid present in 50 ml of solution at the same temperature in a light plastic beaker, the temperature of the mixture rose to 24.1 degrees Celsius. Calculate the heat released and hence the enthalpy change.

Assume that the solutions have the same density and specific heat capacity of water and that no heat is lost to the beaker and surroundings.

NaOH
V = 0.025 L
m = 25 g
T = 296.35 K

HCl
V = 0.050 L
m = 50 g
T = 296.35 K

NaOH + HCl
V = 0.075 L
m = 75 g
T = 297.25 K

ΔT = 0.9 K

q = C x m x ΔT
q = 4.184 x 75 x 0.9
q = 282.42 J