Lab 9.4.4.docx - 1 Suppose you wanted to calculate the heat of reaction for the formation of ammonia gas and gaseous hydrochloric acid(both of which are

# Lab 9.4.4.docx - 1 Suppose you wanted to calculate the heat...

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1. Suppose you wanted to calculate the heat of reaction for the formation of ammonia gas and gaseous hydrochloric acid (both of which are potentially dangerous in gaseous form) from solid ammonium chloride. a. Write a balanced equation for this reaction. the equation for the reaction describe in the question is NH4Cl (s) --> NH3 (g) + HCl (g) the equation of heat reaction : ΔH25° = (ΔH25° NH3 + ΔH25° HCl) - (ΔH25° NH4Cl) NH4Cl (s) -> NH3 (g) + HCl (g) b. The heat of reaction for the process described in (a) can be determined by applying Hess's law. The heats of reaction shown in the table below can be obtained experimentally or looked up in tables of enthalpy data. Which two of these heats of reaction would be the easiest and safest to measure in the laboratory, and which two are better obtained through reference sources? Why? Hint: Consider whether a reaction takes place in aqueous solution or instead involves noxious gases. NH3(g) → NH3(aq)ΔH= -34.64 kJ/mol NH3(aq) + HCl(aq) → NH4+(aq) + Cl-(aq)ΔH= -51.6 kJ/mol HCl(g) → HCl(aq)ΔH= -75.14 kJ/mol NH4Cl(s) → NH4+(aq) + Cl-(aq)ΔH= +14.8 kJ/mo
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