Molar mass:
NO2 = 46.0 g/mol
Pb(NO3)2 = 331.2 g/mol
first calculates the number of moles of NO2 through the stoichiometry of reaction:
2 Pb(NO3)2(g) -------------> 2 PbO(s) + 4 NO2(g) + O2(g)
2 x 331.2 g ------------------> 4 x 46.0 g
16.87 g ---------------------> ? ( mass of NO2)
mass of NO2 = 16.87 x 4 x 46.0 / 2 x 331.2
mass of NO2 = 3104.08 / 662.4
= 4.686 g of NO2
Number of moles:
1 mole NO2 -------------- 46.0 g
? moles NO2 ----------- 4.686 g
4.686 x 1 / 46.0 => 0.101 moles of NO2
1 mole ----------- 22.4 L ( at STP)
0.101 moles ------ ?
0.101 x 22.4 / 1
=> 2.26 L
hope this helps!
