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-balanced chem equation for Hydrochloric acid and ammonia Reaction 2: Sodium hyd

ID: 1059914 • Letter: #

Question

-balanced chem equation for Hydrochloric acid and ammonia

Reaction 2: Sodium hydroxide + Ammonium chloride

Volume (mL) of 2.0 M NaOH(aq) used

25.15

Initial temperature (°C) of the 2.0 M NaOH(aq)

20.57

Volume (mL) of 2.0 M NH4Cl(aq) used

24.75

Maximum temperature (°C) of the 2.0 M NH4Cl(aq)

22.4496

Write the balanced chemical equation for this reaction.

0.75

Determine the T (°C) of the solution surrounding Reaction 2

0.25

Determine the Energy (J) absorbed (+) or released (-) by the solution.

0.75

Determine the Energy (J) absorbed (+) or released (-) by the calorimeter(qcal).

0.75

Determine the Energy (J) absorbed (+) or released (-) by the reaction(qrxn)

0.75

Enthalpy is always reported with respect to a reactant. Calculate the Enthalpy change (kJ/mole), H, for Reaction 2.  Your answer should have the correct sign to reflect whether this is an endothermic or exothermic process.

1

Reaction 2: Sodium hydroxide + Ammonium chloride

Volume (mL) of 2.0 M NaOH(aq) used

25.15

Initial temperature (°C) of the 2.0 M NaOH(aq)

20.57

Volume (mL) of 2.0 M NH4Cl(aq) used

24.75

Maximum temperature (°C) of the 2.0 M NH4Cl(aq)

22.4496

Write the balanced chemical equation for this reaction.

0.75

Determine the T (°C) of the solution surrounding Reaction 2

0.25

Determine the Energy (J) absorbed (+) or released (-) by the solution.

0.75

Determine the Energy (J) absorbed (+) or released (-) by the calorimeter(qcal).

0.75

Determine the Energy (J) absorbed (+) or released (-) by the reaction(qrxn)

0.75

Enthalpy is always reported with respect to a reactant. Calculate the Enthalpy change (kJ/mole), H, for Reaction 2.  Your answer should have the correct sign to reflect whether this is an endothermic or exothermic process.

1

Explanation / Answer

Balanced chemical equation for ammonia and HCl

NH3 + HCl ---> NH4Cl

1 mole of NH3 require 1 mole of Hcl for neutralization

From the data

Total volume of solution = 25.15 + 24.75 = 49.9 ml

density of water = 1 g/ml

So, mass of solution = 49.9 g

dT = 22.4496 - 20.57 = 1.8796 oC

Energy evolved during the reaction = -49.9 x 4.184 x 1.8796 = -393.426 J

Enthalpy per mole = -393.426 J/2 x 0.02475 = -7.93 kJ/mol of NH4Cl

the reaction is exothermic, dH is -ve.