Ihave no more day this is the last one

Which formula can be used to calculate the molar mass of ammonia (nh3)? molar mass of n + molar mass of h 3 × molar mass of n + molar mass of h molar mass of n + 3 × molar mass of h 3 × molar mass of n + 3 × molar mass of h

0.2348 grams of pbcl2 used to form 44.0 ml of solution.

Answer explain why it is not possible to deduce a complete order of reactivity.