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the temperature of the mixture is measured. The experiment is repeated with ammo

ID: 1039587 • Letter: T

Question

the temperature of the mixture is measured. The experiment is repeated with ammonium chloride and again with calcium chloride. 2. A 5.00 g sample of sodium chloride is added to 25.0 mL of water at 20.00. Upon mixing, the salt dissolves and Experiment Salt NaCl NH CI CaCl 20.0? 20.0°C 20.0°C 17.4? 24.4°C (a) Predict the signs of AH for each of the three experiments. Explain your reasoning (b) The AG for each of the experiments is negative. Explain why this is true. (c) Consider the dissolution of ammonium chloride in water. (i) Calculate the enthalpy of the solution in kJ/mol. (ii) Write the thermochemical equation for the dissolution ammonium chloride. (iii) what is the driving force for the change? Use the equation ai-??-Ta S to explain your reasoning. (d) Determine the mass of calcium chloride, in grams, that would be required along with the 5.00 g of NHCI when added to 25.0 mL of water so that the final temperature of the solution is the same as the initial temperature of the water (T T).

Explanation / Answer

a) In case of ammonium chloride

Reason: The temperature of the solution decreases which means the system temperature increases therefore ?H positive and the reaction is endothermic.

In case of calcium chloride

Reason:The temperature of the solution increases which means the system temperature decreases therefore ?H is negative and the reaction is exothermic

In case of Nacl

Reason:There is no change in the temperature between the solution and system therefore ?H is zero the system neither lose heat or gain heat.