First Term Examination
Class: SSS 1
Subject : Chemistry
SECTION A : Objective Tests
Instruction: Answer all questions in this section.
1. What is the mass in gramme of 0.50 moles of oxygen atom? (O = 16) (a) 0.50g (b) 5.0g (c) 8.0g (d) 16.0g
2. How many moles of magnesium atoms are present in 0.80g of magnesium? (Mg = 24) (a) 0.03 moles (b) 0.30 moles (c) 0.31 moles (d) 0.4 moles
3. The mass of 800cm^3 of a gas Q at STP is 1.0g. What is the molar mass of Q? [Avogadros constant = 22. 4cm^3mol^-1]. (a) 18.0g/mol (b) 22.4g/mol (c) 28.0g/mol (d) 36.0g/mol
4. How many moles of oxygen would contain 1.204×10^23 molecules? [ Avogadro’s constant= 6.02×10^23] (a) 1 (b) 2 (c) 4 (d) 3
5. A compound has an empirical formula – Cho and molecular mass of 90. Determine its molecular formula. [C=12, H=1, O=16]. (a) C4H10O2 (b) C4H10O2 (c) C3H6O3 (d) C2H2O4
6. What is the percentage by mass of sodium in Na2CO3. 10H2O? (a) 13% (b) 16% (c) 28% (d) 48%
7. What is the percentage composition of oxygen in K2Cr2O7? (K2Cr2O7 =294; O= 16, K= 39, Cr=52). (a) 14.20% (b) 26.53% (c) 35.37% (d) 38.09%
8. What is the percentage by mass of Sulphur in Aluminum tetraoxosulphate(vi), Al2(SO4) 3? [Al =27, S = 32, O = 16]. (a) 14.71% (b) 21.33% (c) 28.07% (d) 42.66%
9. Consider the reaction represented by the following equation: xKMnO4 + ySO2 + zH2O ==> K2SO4 + 2MnSO4 + 2H2SO4. x, y and z are respectively ; (a) 2, 5 and 2 (b) 2, 2 and 5 (c) 5, 1 and 2 (d) 1, 5 and 2
10. 3Cu and xHNO3 ==> 3Cu(NO3)2 + yNO + 4H2O. In the equation above, the value of x and y respectively are _______ and ________. (a) (b) (c) (d)
11. Mg + 2HCl ==> MgCl2 + H2. From the equation above, what mass of hydrogen would be produced if 12.0g of Magnesium reacted completely with dilute hydrochloric acids? (a) 2g (b) 1g (c) 0.5g (d) 0.1g
12. According to the equation below: CaCO3 ==> Cao + CO2. What volume of Carbon(iv)oxide, CO2, will be liberated at STP from the decomposition of 50g of calciumtrioxocarbonate (iv) [CaCO3 =100g/mol, molar volume of gas at STP = 22.4dm3, C = 12, O = 16, Ca = 40]. (a) 5.6dm3 (b) 6.5dm3 (c) 11.2dm3 (d) 16.8dm3
13. ” All pure samples of the same chemical compound contain the same elements in the same proportion by mass” is a statement of ____________. (a) Gay Lussac’s law (b) The law of conservation of mass (c) The law of multiple proportion (d) The law of constant composition
14. In any chemical reaction, the total mass of product is always equal to that of the reactant. This is a statement of the law of _____________ (a) Conservation of matter (b) Constant composition (c) Multiple proportion (d) Reciprocal proportion
15. Balancing of chemical equation is in accordance with the law of __________________. (a) Multiple proportion (b) Reciprocal proportion (c) Constant composition (d) Conservation of matter
16. A metal M, forms the following chloride MCl2 and MCl3. The chlorides are in accordance with one of the following laws __________. (a) Reciprocal law of proportion (b) Law of conservation of matter (c) Law of multiple proportion (d) Law of constant composition
17. The aim of passing samples Copper(I) oxide over dry hydrogen gas in a combustion tube is to ___________. (a) Convert it to a solid copper (b) Convert it to copper(I) oxide (c) To remove water (d) To remove impurities
18. One of the following apparatus is not required in the verification of the law of definite proportion. (a) Separating funnel (b) U-tube (c) Conical flask (d) Thistle funnel
19. Precipitation reaction takes place in the verification of one of the following chemical laws (a) law of reciprocal proportion (b) law of conservation of mass (c) law of multiple proportion (d) law of constant composition
20. One of the apparatus is not required for the verification of law of conservation of mass. (a) Conical flask (b) Cork (c) Weighing balance (d) Crucible
21. The bond formed when two electrons are shared between two atoms are donated by one of the atoms is ___________. (a) Covalent (b) Dative (c) Ionic (d) Metallic
22. When element 20 Y combines with 8 Z _________________. (a) A covalent compound YZ is formed (b) A ionic compound ZY is formed (c) An ionic compound YZ is formed (d) An ionic compound ZY is formed
23. The ideal gas equation can be written as _________. (a) V1/ T1 = V2/ T2 (b) P1V1 = P2V2 (c) PV = nRT (d) P1V1/T1 = P2V2/T2
24. What is the volume occupied by 2 moles of ammonia at STP? (a) 44.8 dm3 (b) 22.4dm3 (c) 11.2dm3 (d) 5.6dm3
25. The equation P= K/V, illustrates __________. (a) Boyle’s law (b) Charles’ law (c) Dalton’s law (d) Gay Lussac’s law
26. The process whereby a gaseous body loses some of the kinetic energy to a colder body is ___________. (a) Condensation (b) Melting (c) Evaporation (d) Freezing
27. Which of the following is not a postulate of the kinetic theory of gases? (a) Molecule move with the same speed (b) Intermolecular forces are negligible (c) Molecule is in a state of constant motion (d) Collision between molecules is elastic
28. Which of the three states of matter has no fixed shape, no fixed volume and less dense? (a) Gas (b) Solid (c) Liquid (d) Aqueous
29. NH4+ is formed from NH3 and H+ by _________. (a) Covalent bonding (b) Dative bonding (c) Ionic bonding (d) Hydrogen bonding
30. The Vander Waal’s forces are dominant Intermolecular forces (a) Ammonium chloride (b) Chlorine (c) Sodium chloride (d) Water
31. To what temperature must a gas be raised from 273K in order to double both its volume and pressure? (a) (b) (c) (d)
32. Given that ‘r’ is rate of and ‘e’ is density, the expression r @ \|1/e represents _______________. (a) Boyle’s law (b) Charles’ law (c) Dalton’s law (d) Graham’s law
33. The mass of 1400cm3 of a gas Q at STP is 1. 0g. What is the molar mass of Q? (Avogadro’s constant = 22.4dm3) (a) 18.0g/mol (b) 22.4g/mol (c) 28.0g/mol (d) 36.0g/mol
34. The following describes the yellow zone of the Bunsen flame except _________. (a) It is a zone of incomplete combustion (b) The flame is high and wavy (c) It is a non-huminous zone (d) It produces a deposit foot on surfaces in contact with it.
35. The gas used in the filling of meteorological balloons is ___________. (a) Neon (b) Helium (c) Argon (d) Oxygen
36. The gas that slows down rusting and spoilage of food is __________. (a) Oxygen (b) Nitrogen (c) Helium (d) Water vapour
37. Which of the following gases has the lowest diffusion rate under the same conditions of temperature and pressure? [H = 1, O = 16, Ne = 20, CL = 35] (a) Chlorine (b) Hydrogen (c) Neon (d) Nitrogen
38. A given volume of oxygen diffused through a porous partition in 8 secs. How long would it take the same volume of carbon (iv) oxide to diffuse under the same condition? [C = 12. 0, O = 16]. (a) 5.8 secs (b) 6.8 secs (c) 9.4 secs (d) 11.0 secs
39. One of the following is not a characteristic of a non-luminous zone of a Bunsen flame. (a) very hot (b) very clean (c) It is a region of incomplete combustion (d) Has a sufficient supply of air.
40. Which of the following statement about solid is correct? (a) Solids are less orderly than liquid particles (b) Solids have lower density than liquids (c) Solid particles cannot be easily compressed (d) Solids have greater kinetic energy than those of liquid
SECTION B : THEORY
INSTRUCTION: Answer any four questions from this section.
1. Given that 0.101 mole of an oxide X2O weigh 14.4g. Calculate the :
(a) Molar mass of X2O.
(b) Relative atomic mass of X (O = 16)
2a. Calculate empirical formula of the compound below given the following percentage composition by mass; [Ag = 63.50%, N = 8.25%, O = 28.25%] (Ag = silver , N = Nitrogen, O = Oxygen)
2b. Calculate the percentage by mass of sodium in sodium tetraoxosulphate (vi), Na2 SO4 [Na = 23, S = 32, O = 16]
3a. Balance the equation below:
KClO3 ==> KCl + O2
3b. Consider the reaction represented by the following equation:
Zn + 2HCl ==> ZnCl2 + H2
What volume of hydrogen is produced at STP when 13.5g of Zinc react with excess dilute HCl? [ Zn = 54, Molar volume = 22.4 dm3]
4a. State the law of definite proportion.
4b. 1.1g of an oxide of A contained 0.5g of A and 4g of another oxide of A contained 1.6g of A. From your calculations, conclude on the chemical law that values obtained are in accordance with.
5a. Give three (3) differences between covalent compounds and ionic compounds
5b. State Graham’s law of diffusion
5c. A gas occupied a volume of 500cm3 at 17°c and 870mmHg. Calculate the volume of the gas at 10°c and 750mmHg.
6a. Give three (3) postulates of kinetic theory of gases.
6b. State two (2) uses of each of the following :
i. Neon (Ne) ii. Helium (He)
iii. Argon (Ar)
6c. Draw a graphical representation of Charles’ law.