Question

PLS! REPLY FAST I HAVE MY FINAL EXAM AFTER 2 DAYS.... In the below question i dont understand why dont we multiply the value with no of bonds involved.for example on CH4 shouldnt it be (4x413) why in the Q. its taken only 413 and not multiplied by the no: of bond of such type? Q3. Use the following information to answer the next question. Methane (CH4( g )) reacts with chlorine (Cl2( g )) to form chloromethane (CH3Cl( g )) and hydrogen chloride (HCl( g )). The bond enthalpies of C−H, C−Cl, H−Cl, Cl−Cl are 413 kJ mol −1 , 326 kJ mol −1 , 431 kJ mol −1 , and 244 kJ mol −1 respectively. The enthalpy change of the given reaction will be A : − 50 kJ B : − 100 kJ C : − 150 kJ D : − 200 kJ Time Spent: 243 seconds Hide Solution The given reaction can be represented by the following chemical reaction as: From the above equation, we can observe that the reaction involves the cleavage of one C−H bond, one Cl−Cl bond, formation of one C−Cl bond, and one H−Cl bond. We know that, = Total energy required − Total energy required = [413 + 244] − [326 + 431] = − 100 kJ Hence, the enthalpy change of the given reaction is − 100 kJ. The correct answer is B.

Answer 1

Because first we want to add the wt c= 12 and h = 1 so its ch=13 so its 4 times ao ans is 413