Consider the following reaction:

Question

Li2S(aq)+Co(NO3)2(aq)-->2LiNO3(aq)+CoS(s)

What volume of 0.150 M Li2S solution is required to completely react with 125 mL of 0.150 M Co(NO3)2?

Answer 1

Just follow the steps in this worked example. Remember moles = M x L.
http://www.jiskha.com/science/chemistry/stoichiometry.html