Answer:
mass of ZnO = 95.62 g 
Step-by-step explanation:
Balanced chemical equation 
 2ZnS + 3O₂ → 2ZnO + 2SO₂
Given data from eq. 
 moles of zinc sulfide = 2 mol 
 moles of zinc oxide = 2 mol 
 mass of zinc oxide = ?
 Given moles of zinc sulfide = 1.75 mol
Solution 
1st we will find out the mole ratio of zinc sulfide and zinc oxide from balanced chemical equation 
 ZnS : ZnO 
 2 : 2
 2/2 : 2/2 
 1 : 1 
given number of moles of zinc sulfide = 1.75 mol 
So we can find out moles (x) of ZnO needed for 1.75 mol of zinc sulfide 
from the balanced chemical equation the mole ratios are: 
 1 : 1 
 1.75 : x 
Cross multiply these ratios 
 1 × 1.175 = 1x 
 1.175 = 1 x 
 x = 1.175 mol 
Now we will find out the mass of ZnO
 mass = moles × molar mass 
 mass of ZnO = 1.175 mol × 81.38 g/mol 
 mass of ZnO = 95.62 g