How many moles of oxygen are produced by decomposing 40.5 g of h2o2 (molar mass = 34.0 g/mol) according to the equation:h2o2 - - > h2o + o2 (unbalanced) ?

The balanced equation;

2H₂O₂ - - - > 2H₂O + O₂

the stoichiometry of H₂O₂ to O₂ is 2:1

this means that when 2 moles of H₂O₂ decompose, 1 mol of O₂ is formed.

Molar mass of H₂O₂ - 34 g/mol

the mass of H₂O₂ decomposed - 40.5 g

the number of moles of H₂O₂ decomposed - 40.5 g / 34 g/mol = 1.19 mol

according to the stoichiometry of 2:1,

number of O₂ moles formed = 1.19 mol/2 = 0.60 mol