The material covered in this homework assignment relates directly to thermodynam

Question

The material covered in this homework assignment relates directly to thermodynamics. Show all your work. Continuing with the calcite reaction of Homework #5: CaCO_3 (s) + 2HC1 doubleheadarrow C0_2 + H_20 + 2Cl- + Ca^2+ Is the reaction exothermic or endothermic at 600 K? Calculate the entropy for the reaction at 25 degreeC. Using the enthalpy and entropy data at standard conditions, calculate deltaG,degree. Will the react proceed towards the left or right at standard conditions? Molar heat capacities in J mol^-1 K^-1 are

Explanation / Answer

1) Double-replacement reaction. Essentially, the ions switch partners.

CaCO3 + 2HCl ---> CaCl2 + H2CO3

Now, the CaCl2 is a soluble salt, so that's actually just like ions floating around in solution.
The H2CO3 is carbonic acid, which is actually just carbon dioxide, CO2, dissolved in water. The carbon dioxide will immediately come out of solution and bubble out, which is totally observable, just like putting baking soda and vinegar together.

The more complete reaction full ionic equation is the following:
CaCO3 + 2H+ + 2Cl- ---> Ca2+ + 2Cl- + H2O + CO2

It is an exothermic reaction

2) Here Q = -1206.92 Kj = -1206.92* 1000 J

3) delta G   =

        T =   25 degree centigrade = 273 + 25   = 298 K

        entropy = Q/T =   1206.92/298 4 =   4050 J mol^-1 K* -1

3)     At 600 K  

delta G = H - TS = -1206.92*1000 - 600 * 92.9    = - 1151180   reaction is spontaneous

So reaction goes right side

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