Approximately how many moles of n2 are there in 200 moles of clean air?

Well assuming that in air, the composition of gases that are molecular nitrogen or N2 is about 80 percent, then the moles of N2 would be 80 % of 200 or 0.8 of 200 moles which would be 160, about 160 moles of N2 are present in 200 moles of clean air.

Answer is: the equilibrium  shifts toward the reactants, to the left side of chemical reaction.it is because lead(ii) nitrate dissociates in water: pb(no₃)₂ → pb²⁺(aq) + 2no₃⁻(aq).according to lechatelier's principle, the position of equilibrium moves to counteract thechange (more lead cations, common ion), the position of equilibrium will move so that the concentration ofproducts decrease and concentration of reactants of chemical reaction increase.read more on -