Bond Enthalpies Use the bond enthalpies in the table below to determi ne the ent
ID: 571086 • Letter: B
Question
Bond Enthalpies Use the bond enthalpies in the table below to determi ne the enthalpy o f reaction in the following questions: Average Bond Enthalpies (k/mol) Single Bonds C-H 413 348 N-H 391 N-N 163 N-O 201 272 N-C 200 N-Br 243 O-H 463 O-O 146 190 O-CT 203 -I 234 F-F 155 CI-P 253 CI-CI 242 358 485 C-C1 328 Br-P 237 Br-Cl 210 Br-Br 193 S-H 339 327 S-Cl 253 S_Br 218 266 C-1 240 259 H-H 436 H-F 567 H-CI 431 H-Br 366 -Ci 208 175 Si-H 323 S-S 226 Si-C Si-O Multiple Bonds S-S 301 368 614 839 Oa 95 C-C N N 941 S-O S-s 523 418 N891 C-O 799 CHO 1072 9. (2 points) Cl H-C-Cl -Cl+H-CI Cl + O 10. C (2 points) H-C-O-H + H-C-O-H H-C-O-C-H H-O-H + (2 points)Explanation / Answer
The enthalpy of the reaction can be calculated by the net sum of all the bond enthalpies involved in the reaction.
Energy is required to break the bonds and it is released when new bonds are formed.
So here :
Ans 9 :
Bonds broken are H-H and Cl-Cl
Bonds formed are two H-Cl
So enthalpy of reaction = (+436) + (+242) + 2(-431)
= -184 KJ
Ans 10 :
Bonds broken are : three C-Cl and one C-H bonds
Bonds formed are : two C-Cl , one C=O and one H-Cl bonds
So enthalpy of reaction = 3(+328) + (+413) + 2(-328) + (-799) + (-431)
= -489 KJ
Ans 11 :
Bonds broken are : six C-H bonds , two C-O bonds and two O-H bonds
Bonds formed are : six C-H bonds , two C-O bonds and two O-H bonds
enthalpy of reaction = 6(+413) + 2(+358) + 2(+463) + 6(-413) + 2(-358) + 2(-463)
= 0 KJ