Question

2NiS2(s)+5O2(g)=2NiO(s)+4SO2(g)

1. how many kilograms of NiO would be formed from the reaction of .0125 mol of NiS2?

2. How many grams of O2 are needed to cmpletely react with 3.74 g of NiS2.

Answer 1

Convert 0.0125 mol NiS2 to mols NiO. That is 0.0125 mol NiS2 x (2 mol NiO/2 mol NiS2) = 0.0125 mol NiS2 x 2/2 = 0.0125 mol NiO.
Then g = mols NiO x molar mass NiO= ?

For part b convert g NiS2 to mols, convert that to mols O2 and that to grams O2. Follow the steps from part a.