4. Given that 4NH3 + 5O2 4NO + 6H2O, if 4.23 x 1022 molecules NH3 were made to react with an excess of oxygen gas, how many molecules of NO would form? 5. If 0.433 moles of sulfur react with 0.500 moles of chlorine, how many moles of disulfur dichloride are produced? Which reactant is the limiting reactant and which is the reactant in excess?
S8(l) + 4Cl2(g)  4S2Cl2(l)

6. How many grams of Fe2O3 are produced when 2.30x10^24 molecules of O2 are reacted?

7. 3.50 g of potassium reacts with water to produce potassium hydroxide and hydrogen gas.  Calculate the mass of potassium hydroxide produced.  The unbalanced equation is:  K + H2O KOH + H2

Please help as much as possible!