Page 83 - Chemistry_Form_2

Chemistry
for Secondary Schools

(b) State the type of the bond present in the compound. Explain your
answer.

23. A hydrocarbon contains 88.88% carbon and 11.12% hydrogen by mass.
Calculate the empirical formula of the molecule.
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24. A compound consists of calcium 40%, carbon 12% and the rest is oxygen
by mass. Determine the empirical formula of the compound.

25. (a) Calculate the oxidation number of the underlined elements in the
following compounds:
(i) NH Cl (ii) Na SO 4 (iii) Al O (iv) H O 2
4
2
3
2
2
26. Elements T and Q have atomic numbers 12 and 17, respectively. Use the
two elements to answer the following questions:
(a) Write the electronic configuration of element Q.
(b) What is the valency of element T?

(c) Write the chemical formula of a compound formed when T and Q
combine.
(d) Giving a reason predict the type of the bond formed by the combination
of elements T and Q.

(e) In which group and period in the periodic table do elements Q and T
belong?

27. An organic compound contains 26.70% carbon, 2.20% hydrogen and
71.10% oxygen. If its mass is 90 g, determine its molecular formula.

76 Student’s Book Form Two

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