Welcome to your GRADE 12 CHEMISTRY MODEL EXAMINATIONS 2016
GRADE 12 CHEMISTRY MODEL EXAMINATIONS
2016E.C/ 2024G.C
Time Allowed: - 2:30 hours
GENERAL DIRECTIONS
THIS BOOKLET CONTAINS EXAMINATION CHEMSITRY. IN THIS EXAMINATION, THERE ARE A TOTAL OF 80 MULTIPLE CHOICE QUESTIONS. CAREFULLY SELECT THE BEST ANSWER AND BLACKEN ONLY THE LETTER OF YOUR CHOICE ON THE SEPARATE ANSWER SHEET PROVIDED. FOLLOW THE INSTRUCTIONS ON THE ANSWER SHEET AND THE EXAMINATION PAPER CAREFULLY. USE ONLY PENCIL TO MARK YOUR ANSWERS. YOUR ANSWER MARK SHOULD BE HEAVY AND DARK, COVERING THE ANSWER SPACE COMPLETELY. PLEASE ERASE ALL UNNECESSARY MARKS COMPLETELY FROM YOUR ANSWER SHEET.
YOU ARE ALLOWED TO WORK ON THE EXAM FOR 2:𝟏𝟐 HOURS. WHEN TIME IS CALLED, YOU MUST IMMEDIATELY STOP WORKING, PUT YOUR PENCIL DOWN, AND WAIT FOR FURTHER INSTRUCTIONS.
ANY FORM OF CHEATING OR AN ATTEMPT TO CHEAT IN THE EXAMINATION WILL RESULT IN AN AUTOMATIC DISMISSAL FROM THE EXAMINATION HALL AND CANCELLATION OF YOUR SCORE (S).
PLEASE MAKE SURE THAT YOU HAVE WRITTEN ALL THE REQUIRED INFORMATION ON THE ANSWER SHEET BEFORE YOU START TO WORK ON THE EXAMINATION.
DIRECTION: EACH OF THE FOLLOWING QUESTIONS IS FOLLOWED BY FOUR POSSIBLE ALTERNATIVES. CHOOSE THE CORRECT ANSWER AND BLACKEN THE LETTER OF YOUR CHOICE ON THE SEPARATE ANSWER SHEET PROVIDED.
1.
Isotopes are atoms of the same element that is differ in their;
2.
How many electrons are there in d-subshell in the electron configuration of chromium with atomic number 24?
3.
In which of the following blocks of the periodic table does an element with atomic number 14 located?
4.
Which of the following is the most metallic element?
5.
Which of the following substances has the least ionic character?
6.
How many lone pairs are there in the Lewis structure of CCl4?
7.
Which of the following molecules has the strongest London dispersion force?
8.
When the following reaction is correctly balanced, what would be the coefficient of HNO3? Cu + HNO3 → Cu(NO3) 2 + NO + H2O
9.
Given the reaction: 2KNO3 → 2KNO2 + O2, how many moles of potassium nitrate must be decomposed to produce 9 moles of Oxygen gas?
10.
The number of chloride ions in 2 moles of AlCl3 is;
11.
What is the oxidation number of sulphur in the molecule of H2S2O7?
12.
Which of the following is incorrect concerning factor affecting rate of chemical reaction?
13.
Given the reaction: CaCO3 (s) ⇌ CaO (s) + CO2 (g). What is the equilibrium constant expression for the given reaction?
14.
A gas occupies a volume of 5 L at 300 torr. What will be the volume of gas if the pressure increases to 400 torr at constant temperature?
15.
If you heat 5L balloon from a temperature 5 ℃ to 50 ℃, its new volume will be;
16.
Which one of the following has the least rate of diffusion?
17.
An alkane with 19 carbon atoms would have the formula of;
18.
What is the molecular formula of 3, 3-dimethylpentane?
19.
What is the product in the following reaction? CH3CCH+2HCl→
20.
The gas that is widely used for cutting and welding of metals has the formula;
21.
The types of alcohol that is found in all alcoholic beverages like Tella, Areqi, Beer is;
22.
What is the product formed when carboxylic acid reacts with lithium aluminium hydride?
23.
Which of the following is an acidic oxide?
24.
Which one of the following is used as a raw material in the production of nitric acid?
25.
All of the following salts are insoluble in water. EXCEPT;
26.
Which one of the following gas is formed when dilute acid reacts with active metal?
27.
Which of the following species is preferentially discharged at the anode in the electrolysis of brine?
28.
The electrolyte in lead storage battery is;
29.
Which of the following compound is occurs widely in glass, cement and ceramics?
30.
Which of the following element is the third most abundant element in the earth’s crust?
31.
Among the following identify the purest form of iron?
32.
Which of the following is not the use of phosphorus?
33.
What is the Kelvin scale corresponding to the temperature readings when the degree Celsius (°C) is equal with the degree Fahrenheit (°F)?
34.
Which of the following is possible while doing an experiment?
35.
What is the ratio of the energy of a photon of 300nm wavelength radiation to that of 600nm radiation?
36.
The ejection of electron from metals by shining light on the metal surface is;
37.
Which of the following shows the correct order of filling orbitals for given subshells?
38.
What is the number of unpaired electrons in the electron configuration of iron? (Z = 26)
39.
Which of the following compounds would be expected to have the highest melting point?
40.
How many bonding and lone pairs, respectively does the molecule CO2 have? (126C, 168O)
41.
Which of the following molecule has see-saw shape?
42.
Which of the following is not correctly matched the molecule and hybridization around the central atom?
43.
If we increase the concentration of a reactant, what happens to the collisions between particles?
44.
The reaction between NO and I2 is second order in NO and first order in I2. What change occurs in the rate of reaction if the concentration of each reactant is tripled?
45.
Suppose reactions: A → B and B → A are both elementary processes with rate constant of 800-1 and 4000 S-1 What is the value of the equilibrium constant for A ⇌ B?
46.
Consider the reaction: N2 (g) + O2 (g) ⇌ 2NO (g), ΔH = +180 KJ/mol the production of NO is increased by;
47.
Which of the following acid is used as chemical defense for ants?
48.
An alcohol produced in the manufacturing of soap is;
49.
Which of the following is correct about the base according to the Arrhenius concept?
50.
All of the following is a conjugate acid-base pair. EXCEPT;
51.
Which of the following statement is true about the percent ionization of weak acid?
52.
All of the following combination can produce a buffer solution. EXCEPT;
53.
If CH3COONa is added to a solution containing CH3COOH, which of the following statements is true?
54.
The salts of which of the following weak acid will be the most hydrolyzed?
55.
The acid-base indicator methyl orange has a Ka value of 1 x 10−6. Its acidic form is red while its basic form is yellow. If methyl orange is added to a solution with a pH = 7, the color of the solution will be;
56.
Which of the following titration will have an equivalence point at a pH > 7?
57.
Given the reaction: H2S + HNO3 → S + NO + H2 Which of the following is correct about the given chemical reaction?
58.
Which of the following pairs of the charge carrier is selected by the electrode in the electrolysis of dilute NaCl solution?
59.
Two cells are connected in series. One contains AlCl3 and the other contains AgNO3 as the electrolytes. What mass of Ag is deposited when 1.8 g of Al is deposited at cathode?
60.
The process of coating less active metal on the surface of more active metals using electrolysis is;
61.
Which of the following is not correct about electrolytic cells?
62.
Which of the following is correct about the galvanic cells?
63.
All of the following is the purpose of salt bridge in the galvanic cells. EXCEPT;
64.
Which of the following statement cannot describe the characteristic of chemical industries?
65.
All of the following is non-renewable natural resources. EXCEPT;
66.
All of the following is correctly matched with its manufacturing process. EXCEPT;
67.
Which of the following is the chemical formula of soda ash?
68.
What is the chemical formula of oleum?
69.
Which of the following bacteria can convert ammonium ion (NH+4) to nitrate ion (NO−3) in the soil?
70.
Which of the following are the traditional methods of food preservation?
71.
Which of the following are the major raw materials for the production of Portland cement?
72.
Which of the following are the correct steps for the production of sugar?
73.
Which of the following sequential steps are correct in the preparatory stages of tanning?
74.
Which of the following substance would be the possible repeating unit for natural rubber?
75.
Which of the following substance would be the possible repeating unit for polyethylene terephthalate?
76.
Sucrose is the most abundant disaccharide carbohydrate made up of which kind of monomer?
77.
What types of polymerizations occurs when ethylene glycol reacts with terephthalic acids to form polyester?
78.
Which of the following components of the environment is composed of 78 % of nitrogen, 21 % of oxygen and 1 % of other gases?
79.
All of the following is the methods of reducing air pollution. EXCEPT;
80.
Which of the following methods cannot be used to reduce water pollution?
