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Essay questions for 2010
3. State and explain the trend in the acidity for HCl,HBr
and HI in an aqueous solution. 
5. A Scientist discovered a new element with a proton number of 119 and a valence electronic configuration of 8s1 . Predict the postion of the element in the Periodic Table and state three physical properties and three chemical properties fo the element.
6. Caesium is used in photoelectric cells because its atom loses electrons readily when exposed to light. Explain the ease of losing electrons for caesium. 
7. Boric acid, B(OH)3, is an antiseptic found in
some eyewash. In an aqueous solution, boric acid acts as a Lewis acid.
8. Phenol is weak organic acid, explain why phenol is a weak organic acid. 
2.Phenolphthalein,HPh, is an acid-base indicator in the pH
range between 8.2 and 9.8. The equilibrium equation of phenolphthalein in
aqueous solution is as follows.
3.a) An element X is in group 9 and Period 4 in the
4.Using carbon as an example, explain the following terms
5. a) Giving suitable examples, explain what is meant by polar molecules and nonpolar molecules. 
6. Explain the following observations
7.Explain the term dynamic equilibrium. 
8. In the reaction 2CO2(g)↔2CO(g) +
1. Derive an expression for the solubility product, Ksp, of barium hyfroxide. Explain why aqueous barium nitrate forms a precipitate with aqueous sodium hydroxide but not with aqueous ammonia. 
2 . Pure nitric acid is a colourless liquid which forms an azoetropic mixture with water. Aqueous nitric(V) acid shows a negative deviation from Raoultís Law. Explain why aqueous nitric(V) acid shows aa negative deviation from Raoultís Law. 
3. Dmitri Mendeleev is acknowledgeed by scientists as the founder of the modern periodic table.i) What is the basis of the Mendeleevís Periodic Tableii) Based on his Periodic Table, Mendeleev successfully predicted the properties of some elements that had been discovered. Name one of the elements. 
4.Explain what is the difference between the terms orbit and orbital? 
5. Explain what is meant by hydrogen bonding using hydrogen fluoride as an eg. 
6. A mixture of heptane(bp= 98oC) and octane(bp=126oC) forms an ideal soln. Explain in terms of intermolecular forces, why this mixture shows an ideal behaviour.
7. Explain the principle of steam distillation. What factors determine the percentage of organic substances in the distillate. 
8. State the partition law. Under what conditions can this law be applied