[jigglywiggly]

what is the sign of ΔH for the reaction CoCl4 2-(aq) + 6H2O(l) =Co(H2O)6 2+(aq) + 4Cl-(aq)? Does a change in the solution’s color indicate a “favored” direction of the equilibrium?

I don't see how you can possibly know this just with the information given...?

[DevaDevil]

what doe delta H say of the preferred direction of the reaction?

what does the color change mean in terms of which side the equilibrium shifts?

[Viking]

CoCl4 2-(aq) + 6H2O(l) = Co(H2O)6 2+(aq) + 4Cl-(aq)

ΔH = Products - Reactants
ΔH = (Co(H2O)6 + 4Cl) - (CoCl4 + 6H2O)

I looked through my tables that i have and i could not find the ΔH for CoCl4 & Co(H2O) but i do have these to help you

ΔH of H2O(l) = -285.8 * 6 = -1714.8 kJ/mole
ΔH of Cl-(aq) = -167.2 * 4 = -668.8 kJ/mole

This data is also assuming that the equation is currently under standard conditions (25 Celsius & 1 atm)
You need to know what the original ΔH is for the other 2 compounds.

This is all i can help you with for the information you provided =/ sorry

[fledarmus]

Nice information if you are trying to calculate the delta H Viking, but that shouldn't be necessary to answer the question. I believe the hints that DevaDevil provided are sufficient...

[Viking]

I suppose so, but i think jiggly is looking for the answer and not just hints. Correct me if im wrong but i think that the solution will get darker moving to the left (or change color). and this can be done by either adding heat or cooling down the solution. If adding heat to the solution makes it darker (or changes color) then you can conclude that the ΔH is negative

[DevaDevil]

he may have been looking for the answer, yes, but an answer you get to yourself by reasoning sticks. An answer you get and then just copy/pastes teaches nothing. That is why I tend to give hints rather than answers