Calculating Entropy of Reaction: [Co(H2O)6]2+ + 4Cl- → [CoCl4]2- + 6H2O

[kevinnn]

Im going to try my best to write out this chemical equation. Also I'm going to write a forward arrow but it's really it should be the equilibrium arrows.

[Co(H2O)6]2+ + 4Cl- --> [CoCl4]2- + 6H2O

Sorry for that, I don't know how to use the math font or whatever it's called.

The question is whether the reaction is exothermic or endothermic. I think reaction is endothermic. Cobalt chloride is a red color and when we heated a solution of it in the presence of hydrochloric acid it turned a dark blue color. A possible solution I thought of as to why it's endothermic is because energy is required to break the attractions between the cobalt ion and the water molecules. I believe that is called a metal ion complex, correct? I'm very unconfident about this answer. Can I please get some feed back? Thanks.

 

[jbsteele]

Yes, your explanation is correct. The reaction is endothermic because energy is required to break the attractions between the cobalt ion and the water molecules. This type of reaction is called a metal ion complex. When the reaction is heated, the bonds between the cobalt ion and the water molecules are broken and the reaction releases energy. This energy is used to form new bonds between the cobalt ion and the chloride ions.