# why do solids and pure liquids have no effect on yield and equilibrium? [duplicate]

There are three parts to my question.

Part one:

• Let's assume we have a reversible reaction at equilibrium as follows : Calcium carbonate (solid) goes into calcium oxide(solid) and carbon dioxide(gas).
• Let's assume that I add more calcium carbonate i.e I add more solid.
• Now I understand that there would be no shift in the position of the equilibrium since we added a solid therefore we induced a very negligible change in concentration , but what I am confused about is doesn't more reactant mean more product and doesn't more product symbolise a shift to the right?

Part two:

• I have read that the equilibrium constant $Kc$ and $Kp$ are really just close approximations of the true thermodynamic constant which uses activities hence the activity of a solid and pure liquid is always 1 .
• However upon further research I discovered that for an esterification reaction the equilibrium constant is 4 -First of all, the above reaction involves all pure liquids and hence the thermodynamic equilibrium constant would be one ,however why stick to a value of 4 why not easily say it is one since all activities are 1.

Part three:

• If we do take pure liquids in the $Kc$ value how do you measure the concentration of such a species, wouldn't the value be very high.My intution tells me that pure liquids are only taken when a reaction only involves pure liquids only , but they are not taken in heterogeneous reactions or when the liquid involved acts as a solvent as well.However in a case of a heterogeneous reaction only involving solids and liquids what will your equilibrium constant look like .

Lastly I have no knowledge of thermodynamics and I am still a high school student .

• Jun 15 '17 at 21:35
• If there are three parts of a question, than it is easier to tackle each of them as an individual question. Otherwise, the question may be considered as too broad to be answered. Jun 15 '17 at 22:11
• Regarding your first part, although more reactant means more product, the percentage yield is the same and thus, there is no shift in the position of equilibrium. Jun 16 '17 at 0:48