Qualitative Analysis: Calcium & Copper Reactions Explained

[Celluhh]

I'm just learning the basics, but I have a few questions.
Why is it that there is no precipitate formed when calcium ions react with aqueous ammonia?
Why is it that copper ions reactwith A little aqueous ammonia to form copper hydroxide precipitatinput dissolves in excess aqueous ammonia to form a solution?
All help will be greatly appreciated thank you !

 

[sgstudent]

Aqueous ammonia partially dissociate into NH4+ and OH- ions. So any calcium hydroxide formed will be a minute amount hence, it is able to dissolve in water leaving no precipitate. Copper (ii) hydroxide continues to react with the solution to form a deep blue solution.

 

[Borek]

Do you know what solubility product is? If so, compare solubility products of calcium hydroxide and copper hydroxide - which one is more soluble? Which one is easier to precipitate out of the solution?