$7.$ For the reaction: N$2($B$)+3$ H$2($g$)+2$NH$3()$ a$)$ make a diagram similar to that in Figure $1.$ b$)$ calculate AH based on your diagram. $8.$ Using grammatically correct sentences, describe how to calculate the Art for the reaction in CTQ $7$ given the AH e of the three species. $9.$ For any given chemical reaction, if the sum of the enthalpies of atom combination for all of the reactants is more negative than the sum of the enthalpies of atom combination for all of the products, will the value of AHF for the reaction be positive or negative? Explain your reasoning.