PLS HELP ASAP. *IF* THE ANSWER IS CORRECT I'LL MARK YOU AS BRAINIEST: Which is an example of mechanical weathering?

a) iron oxide

b) water moving over rocks

c) limestone cave formations

d) hydrated minerals

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?