What do coefficients in chemical equations tell you?

Consider the reaction: n2(g) + o2(g) ? 2no(g) kc = 0.10 at 2000oc starting with initial concentrations of 0.040 mol/l of n2 and 0.040 mol/l of o2, calculate the equilibrium concentration of no in mol/l how would this be done?

Nonpoint source pollution is difficult to control because it

How many moles are contained in 5.6 l of h2 at stp