2no(g o2(g → 2no2(g how many grams of o2 are needed to produce 1.31 g of no2

2NO + O₂ → 2NO₂

If mass of NO₂ = 1.31 g

then moles of NO₂ = =

                               = 0.0285 mol

The mole ratio of O₂ : NO₂ based on the equation is 1 : 2.

∴ if moles of NO₂ = 0.0285 mol

then moles of O₂ = 0.0285 mol ÷ 2

                            = 0.01425 mol

Grams of O₂ needed = mole × molar mass

                                  = 0.01425 mol × (16 × 2) g/mol

                                  = 0.456 g

The total number of electrons is 14