Answer:
23.37 g
Explanation:
To find the grams of O₂ used, you have to convert the grams of NO₂ to moles of NO₂, then to moles of O₂, then to grams of O₂. You need the molar mass of both substances; O₂ has a molar mass of 32.00 g/mol and NO₂ has a molar mass of 46.01 g/mol. The ratio of O₂ to NO₂ 1:2.
[tex]67.21gNO2*\frac{1 mol NO2}{46.01gNO2} *\frac{1mol O2}{2 mol NO2} *\frac{32.00gO2}{1mol O2} = 23.3723gO2[/tex]
Then you round to the lowest number of significant figures = 23.37 g O₂
