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Enthalpy is always reported with respect to a reactant. Calculate the Enthalpy c

ID: 1062509 • Letter: E

Question

Enthalpy is always reported with respect to a reactant. Calculate the Enthalpy change (kJ/mole), ?H, for the Reaction .  Your answer should have the correct sign to reflect whether this is an endothermic or exothermic process.

Enthalpy is always reported with respect to a reactant. Calculate the Enthalpy change (kJ/mole), ?H, for the Reaction .  Your answer should have the correct sign to reflect whether this is an endothermic or exothermic process.

Volume (mL of 2.0 M (aq) used Initial temperature (°C) of the 2.0 M NaoHaq Volume (mL) of 2.0 M (aq) used Maximum temperature (°C) of the 2.0 M NH4Claq) 26.0 20.789 25.0 22.3054

Explanation / Answer

Q = m c T
Q = quantity of heat in joules (J)
m = mass of the substance acting as the environment in
grams (g)  = 26+25 = 51
c = specific heat capacity (4.19 for H2O) in J/(g oC)
T = change in temperature = Tfinal - Tinitial in oC = 22.3054 - 20.789 = 1.5164 oC

Using this equation let us find out Q

Q = 51 x 4.18 x 1.5164 = 323.266 Joules

323.266 Joules of heat released for 51 ml of 2 M solution

Hence enthalpy of reaction = 323.266 / 0.051 Lit x 2M = 3169.274 Joules