SL-F4-Chemistry-2009-exam-pdf - Webs
SL-F4-Chemistry-2009-exam-pdf - Webs
SL-F4-Chemistry-2009-exam-pdf - Webs
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Somaliland National Examination Certificate of Secondary Education<br />
and Certification Board <strong>Chemistry</strong>, <strong>2009</strong><br />
PART 3: EXTENDED QUESTION (10 MARKS)<br />
Answer one question only<br />
1. Ammonia gas is produced for commercial purposes in industry by the Haber process;<br />
see the equation.<br />
N2 (g) + 3H2 (g) 2NH3 (g)<br />
The following two tables show the enthalpy change for reaction of making ammonia in the<br />
Industry.<br />
Enthalpy change from bond breaks in the reactants;<br />
Bonds<br />
N N<br />
H H<br />
Bond enthalpy<br />
(Kj mol)<br />
945<br />
436<br />
17<br />
Number of<br />
bonds broken<br />
______<br />
Enthalpy change from bond formed in the products;<br />
Bonds<br />
N H<br />
Bond enthalpy<br />
(Kj mol)<br />
391<br />
3<br />
Number of<br />
bonds broken<br />
_______<br />
Total enthalpy<br />
input (Kj mol)<br />
945<br />
_______<br />
2253<br />
Total enthalpy<br />
input (Kj mol)<br />
2346<br />
a) i. Calculate the missing values and fill in the table. (3 marks)<br />
© <strong>SL</strong>NECB, <strong>2009</strong>
Change language