Second Term Examination
Class: SSS 2
Subject: Chemistry
Name : _______________________________________
Instruction: Read and answer all questions.
SECTION A : Objective Test
1. What pH value indicates a basic solution? (a) – 1 (b) 3 (c) 7 (d) 9
2. In the following reaction, 2SO2 + O2 = 2SO3 (DH = – 395.71KJmol-1). The forward reaction is _________. (a) Endothermic (b) Exothermic (c) Closed (d) Constant
3. In the electrolysis of brine, the anode must be carbon because ________. (a) carbon is a reducing agent (b) Chlorine does not reduce carbon (c) Carbon produces discharge of chlorine (d) Chlorine attacks other elements but not carbon
4. In the periodic table, elements are arranged according to their _______. (a) atomic masses (b) valency electron (c) mass number (d) atomic number
5. What quantity of electrons (in moles) is lost when one mole of iron (II) ions is oxidized to iron (III) ions ? (a) 5 moles (b) 1 mole (c) 4 moles (d) 3 moles
6. Which of the following is the relative molecular mass of a compound which has empirical formula CH2O? [H=1, C=12, O=16] (a) 30 (b) 46 (c) 50 (d) 60
7. The position of equilibrium in a reversible reaction is affected by _________ (a) mass of the reactants (b) change in the concentration of the reactants (c) change in the size reaction vessels (d) presence of catalyst
8. The use of diamond in abrasive is due to it’s __________. (a) High melting point (b) density (c) durability (d) hardness
9. The following oxides react with water except ___________. (a) Na2O (b) NO (c) SO3 (d) CO2
10. What mass of copper would be deposited by a current of 1.0 ampere passing for 965 seconds through copper (II) tetraoxosulphate (vi) solution? [Cu=63.5, 1F= 96500C] (a) 6.35g (b) 0.318g (c) 0.635g (d) 3.18g
11. How many electrons are removed from Cr3+ when it is oxidized to CrO2? (a) 2 (b) 71 (c) 4 (d) 8
12. Which of the following is a neutral oxide? (a) Nitrogen(I) oxide (b) Carbon(IV) oxide (c) Sulphur(IV) oxide (d) Phosphorus(V) oxide
13. The spontaneity of a chemical reaction is determined by the change in the _________. (a) concentration of the reactants (b) temperature of the system (c) free energy of the system (d) pressure applied to the system.
14. What is the percentage by mass of Sulphur in Al2(SO4)3? [Al2(SO4)3 = 342 mol; S=32, O=16, Al =27] (a) 9.36% (b) 14.71% (c) 20.07% (d) 21.33%
15. In the reaction below, the arrow indicates that the reaction N2O4 <===> 2NO2 is ____________. (a) Endothermic (b) irreversible (c) reversible (d) exothermic
16. The IUPAC name for Ca(NO3)2 is _________. (a) Calcium oxide (b) Calcium Nitrogen (c) Calcium tetraoxide (d) Calcium trioxonitrate
17. Elements in the same group in the periodic table have same ________. (a) number of Valence electrons (b) number of shells (c) atomic number (d) electronic configuration
18. The following are the uses if ammonia except __________. (a) it is used in the softening of temporary hard water (b) it is used as a cleaning agent (c) it is used for production of nylon (d) it is used for production of paint
19. The oxidation number of Sulphur atom in the compound H2SO4 is _______. (a) – 3 (b) +4 (c) +6 (d) – 5
20. The green house effect is a climatic condition associated with the presence of excess __________ . (a) CO2 (b) H2O (c) NO (d) NH3
21. What process is illustrated by the following equation? NaCO3. 10H2O ==> NaCO3 + 10 H2O (a) Deliquescence (b) Hygroscopy (c) Efflorescence (d) Hydrolysis
22. What quantity of silver is deposited when 9650C electricity is passed through AgNO3? [Ag = 108, 1F = 96500C] (a) 1.8g (b) 540g (c) 21.6g (d) 10.8g
23. The following elements are transition elements except ________. (a) Chromium (b) Cobalt (c) Boron (d) Nickel
24. The reaction of alkanes are mainly ________ (a) Addition reaction (b) Polymerization reaction (c) Substitution reaction (d) dehydration reaction
25. The allotropes of Sulphur are ____________. (a) diamond and graphite (b) diamond and rhombic (c) graphite and monoclinic (d) rhombic and monoclinic
26. A measure of the degree of disorderliness in a chemical system is known as ____________. (a) Activation (b) enthalpy (c) entropy (d) equilibrium
27. The minimum energy required by reactant before activation takes place is known as ___________. (a) potential energy (b) activation energy (c) kinetic energy (d) mechanical energy
28. Which of the following is a base but not in alkaline? (a) NaOH (b) MgO (c) Ca(OH)2 (d) KOH
29. Which of the following processes is Endothermic? (a) Slaking of quick lime (b) Combustion of graphite (c) Formation of ammonia (d) Dissloution of Potassium trioxinitrate (V) in water
30. In acid-basé titration, the color of the methyl orange indicator at the equilibrium point is _______. (a) yellow (b) orange (c) red (d) pink
31. The solubility of alcohols in water is due to __________ (a) covalent nature (b) hydrogen bonding (c) thier ionic character (d) their low boiling point
32. Which of the following does not affect the discharge of ions during electrolysis? (a) Position of the ions in the electrochemical series (b) Concentration of ions (c) Nature of electrode (d) Temperature of solution
33. When an element can exist in two or more forms in the same physical state, the element is said to exhibit _________ (a) Isotopy (b) Allotropy (c) Isomerism (d) Hygroscopic
34. What is the concentration in mol/dm3 of à solution containing 0.10g of sodium hydroxide per 50cm3 of solution [NaOH= 40]? (a) 0.05 (b) 2 (c) 0.1 (d) 0.5
35. 50cm3 of saturated solution of potassium trioxinitrate (V) at 40°C containing 5.50g of salt. What is the solubility of potassium trioxonitrate(V) at 40°C? [KNO3 = 101] (a) 1.0 mol/dm3 (b) 1.5 mol/dm3 (c) 2.0 mol/dm3 (d) 2.5 mol/dm3
36. The atomic mass of an atom is mostly due to the mass of ________ (a) electron and proton (b) electron and neutron (c) atomic number and proton (d) proton and neutron
37. Which of the following statement is not correct if group 7 elements? (a) They are good oxidizing agents (b) They are diatomic (c) They have relatively low ionization potential (d) They have high electron affinity
38. What is the value of “n” in the following redox reaction: XO4 + 8H+ + ne- => X2+ + 4H2O? (a) 2 (b) 3 (c) 4 (d) 6
39. The accompanying heat of reaction represented by the equation H2O => HO2 is described as the heat of _________. (a) solution (b) neutralizing (c) vaporization (d) sublimation
40. The reaction represented by the equation: NaOH + HCl ===> NaCl + H2O is ___________. (a) neutralization reaction (b) a double decomposition (c) reversible (d) usually catalyzed
SECTION B: THEORY
INSTRUCTION: Answer only 3 questions
1a. State Le’ chatelier’s principle
1b. Give the names of two allotropes of Sulphur.
1c. Write the general molecular formula for :
i. Alkanes ii. Alkynes iii. Alkenes
1d. Calculate the mass of silver deposited when a current of 2.6 A is passed through a solution of silver salt for 70 minutes (Ag = 108, 1F = 96500C)
2. Consider the reaction represented by the equation: 2SO2 + O2 <===> 2SO3 DH =188KJ.
a. Write an equation for the equilibrium constant.
b. Sjet H an energy profile diagram for the forward reaction showing the profile for the catalyst system.
c. Distinguish between exothermic and Endothermic reaction.
3a. State and explain what is observed when Sulphur(IV) oxide is bubbled through acidified potassium tetraoxomanganate (VII) solution.
3b. List the product of the reaction of sulphur(IV) oxide with hydrogen sulphide
4a. Define the following terms:
i. Haber process
ii. The Frasch process
iii. Exothermic reaction
iv. Spontaneous reaction
4b. List the factors that affects any system at equilibrium and explain how two (2) of the factors listed above affects a system of equilibrium.
ALTERNATIVE TO PRACTICAL.
INSTRUCTION: Answer any two questions from this section.
1. A solution of 0.01M HCl was titrated against 25cm3 of 0.05M NaOH. (H=1, O=16, Na=23, Cl=35.5)
i. Write a balanced chemical equation for the reaction.
ii. Determine the volume of the acid used.
iii. Determine the concentration of the acid and alkaline in g/dm3
2. Calculate the volume of a 12.0M HCl that should be diluted with distilled water to obtain 1.0dm3 of a 0.05M HCl.
2b. What volume of distilled water should be added to 400cm3 of 2.0M H2SO4 to obtain 0.2M of solution?
3a. Write the suitable indicator for the following acid-base titration.
i. Strong acid VS Strong base: ________________
ii. Strong acid VS Weak base: _________________
iii. Weak acid VS Strong base: _________________
iv. Weak acid VS Weak base: __________________
3b. Write two (2) precautions to be taken during titration.