In: Chemistry
CH4(g)+Cl2(g)---->CH3Cl(g)+HCl(g)
A) Use bond energies to cal. delta H
My Ans: - 110 KJ/mol
B) Use the enthalpy of formation to cal. delta H
My Ans: 103 KJ/mol
C) Explain why A and B are not the same?
D) Calculate % error?
Since you have calculated answers of part A and part B. So I am solving part C and part D here:
C) A and B are not same because while calculating bond energies we take the average value.
Like if we talk about a C-H bond then average value of all the C-H bonds in all the known molecule will be the values of bond energy of C-H bond. Now if we use this value to calculate H of reaction then it will surely differ form the value calculated using enthalpy of formation because enthalpy of formation of every molecule is different.
D) % error = (Difference in values / True value) x 100
= (7/103) x 100
= 6.8%