Please help what are the answers

Hey guys so i need to know what is _nh3+> nh4oh ~chemistry~

If 3 moles of a compound use 24 j of energy in a reaction, what is the a hreaction in j/mol?

Insoluble sulfide compounds are generally black in color. which of the following combinations could yield a black precipitate? check all that apply. na2s(aq)+kcl(aq) li2s(aq)+pb(no3)2(aq) pb(clo3)2(aq)+nano3(aq) agno3(aq)+kcl(aq) k2s(aq)+sn(no3)4(aq)