Homogenous vs Heterogenous

[Claire_Sabol_2G]

Hello! I was looking back through my notes from Week 1, and I noticed we defined homogenous and heterogenous equilibrium. I completely understand their definitions, but I was wondering what the significance of this was. I don't remember if whether or not equilibrium was homogenous led to any changes in solving equilibrium equations. Are these just definitions to know for now, or will they make a difference in future problems?

[Jessica Tam 3H]

Hi,
This is important to know because if something is homogenous, we can calculate Kp or Kc without having to do any conversions. If something is heterogenous, then when we calculate K, we would exclude pure solids and solvents because you can't get the concentration of a solid and pure solvents would be in excess for a reaction. Also, if there is, say, a mix of gas and aqueous molecules in a reaction and the partial pressure is given for the gas, you would have to convert the gas into concentration using the ideal gas law PV=nRT.

[Hannah Jin 1J]

For heterogeneous equilibrium, we need to pay attention to the phases of reactants and products in order to calculate equilibrium constants. Liquids, solids, and solvents are not included in this calculation.

[Alison King 3L]

For heterogeneous equilibrium, we don't include solids and liquids in the equilibrium constant, so you would have to take that into account when doing an ICE table.

[Rebekah Jung 1C]

It is important to pay attention as to what phases the reactants and products are in because in heterogeous reactions, we would exclude liquids and solids in our ICE table.

[Thailer Phorn 1C]

It is significant because with heterogenous reactions, you have to pay attention to the reactants' and products' phases, as liquids and solids are excluded from the ICE table.