The mass of an element is 27 and its atomic number is 13. What is the composition of the nucleus of its atom?
Απάντηση
(C)
13 protons and 14 neutrons
2
Which of the following electron transition results in the emission of energy?
Απάντηση
(A)
3p to 3s
3
Which of the following properties of elements deceases generally across a period in the Periodic Table?
Απάντηση
(C)
Atomic radluc
4
Which of the electrons in the following orbitals will experience the greatest nuclear attraction?
Απάντηση
(A)
1s electron of helium
5
A nuclide emits a beta-particle (e) in the process, that atomic number
Απάντηση
(A)
increases by 1 while the mass numer remains constant
6
One of the characteristics of transition metals is
Απάντηση
(D)
formation of coloured ions
7
A metal X forms two chlorides with the formulae XCI2 and XCI3. Where is X in the Periodic Table?
Απάντηση
(C)
d-block
8
A metal X forms two chlorides with the formulae XCI2 and XCI3. Where is X in the Periodic Table?
What type of bonding exists between X and chlorine in each of the chlorides?
Απάντηση
(B)
ionic bonding
9
Which of the following equipment is not used to detect radioactivity?
Απάντηση
(C)
Mass spectrometer
10
The method of collection of gases prepared in the laboratory depend on their
Απάντηση
(D)
solubility and density
11
Which of the following pairs of salts undergo hydrolysis?
Απάντηση
(A)
AlCI3 and NH4CI
12
The alloy used extensively in the building industry is
Απάντηση
(A)
steel
13
Which of the following salts is not prepared by precipitation?
Απάντηση
(C)
Sodium trioxocarbnate (IV)
14
What volume of hydrogen would be left over when 300cm3 of oxygen and 1000cm of hydrogen are exploded in a sealed tube? [2H2(g) + O2(g) → 2H2 Og]
Απάντηση
(B)
400 cm3
15
What are the values of x, y and z respectively in the following in the following equation? \(MnO_{2(s)} + xHCI_{(aq)} → MnCI_{2(g)} + yHO_{(l)} + zCI_{2(g)}\)
Απάντηση
(D)
4,2,1
16
Which of the following subtances will not produce effervescence with dilute hydeochloric acid?
Απάντηση
(D)
Sodium chloride
17
What quantity of electrons in moles is needed to discharge two moles of aluminum from aluminum oxide (AI 2O3)
Απάντηση
(D)
6
18
Two solutions containing Pb2+ and AI3+ respectively can be distinguished using
Απάντηση
(D)
conc. HCI
19
A solution of zinc chloride should not be stored in a container made of
Απάντηση
(C)
aluminium
20
Glucose gives a brick-red precipitate with Fehling's solution because it is
Απάντηση
(C)
a reducing sugar
21
What is the IUPAC name of CH3CH2COOCH 3?
Απάντηση
(C)
Methylpropanoate
22
The mass of 800cm3 of a gas X at s.t.p. is 1.0g. What is the molar mass of X? [1 mole of a gas at s.t.p occupies 22.4dm 3]
Απάντηση
(C)
28.0gmol-1
23
Which of the following compounds is a soapless detergent?
Απάντηση
(A)
C 12H 25OSO3Na
24
The reaction that takes place at the cathode when an aqueous solution of NaCI is electrolysed using carbon electrodes is
Απάντηση
(A)
2H+2(g) + 2e- → H2(g)
25
What of the following pairs of acid and base will produce a solution with pH less than 7 at equivalence point?
Απάντηση
(C)
HCI and Mg(OH) 2
26
WHICH OF THE FOLLOWING SALTS IS READILY SOLUBLE IN WATER?
Απάντηση
(B)
Pb(NO 3) 2
27
Which of the following factors that affect the rate of chemical reactions can be explained in terms of the collision theory? l. concentration ll. pressure lll. temperature lV catalyst
Απάντηση
(D)
l, II, lll and IV only
28
An orange drink concentrate is suspected to contain traces of poisonous green dye and a harmless dye having the same boiling point. Which of the following techniques is most suitable for isolating the dyes?
Απάντηση
(B)
Paper chromatography
29
If 60 cm3 of gas is heated from 27oC TO 50oC, what is the new volume of the gas at constant pressure?
Απάντηση
(C)
64.6cm3
30
Consider the cell represented below: Zn/Zn2+(aq) // Cu2+(aq) / Cu(s). Which of the following statements is correct about the cell
Απάντηση
(A)
Zn is oxidized to Zn2+
31
When ammonium trioxocarbonate (IV) solution is added to separate solutions of calcium, zinc and sodium salt precipitate could be formed in the case of
Απάντηση
(C)
calcium and znic only
32
The condensation of several amino acid molecules gives
Απάντηση
(D)
proteins
33
Which of the following statements is true of an endothermic reaction? I. Heat is absorbed from the surrounding II. The heat content of the products is more than that of the reactants III. The enthalpy change is positive IV. The surrounding is at a lower temperature than the system.
Απάντηση
(C)
l,ll and lll only
34
What is the change in the oxidation number of 1- in the reaction represented by the following equation? 51 -1(aq) + 6H+(aq) + 1O-3(aq) → 312(g) + 3H2O(l)
Απάντηση
(B)
-1 to 0
35
The key factor to be considered in siting a chemical industry is
Απάντηση
(D)
its nearness to the source of raw materials
36
Which of the following reactions will be affected by change in pressure at equilibrium?
Απάντηση
(B)
X(g) + 2Y(g) ⇌W(g) + Z(g)
37
WHICH OF THE FOLLOWING PETROLEUM FRACTIONS YIELDS VASELINE AND PARAFFIN WAX ON REDISTILLATION?
Απάντηση
(B)
LUBRICATION OIL
38
What is the product Cx Hy in the following equation? \(C_{10}H_{22}\) → \(C_{8}H_{18}\) + CxHy
Απάντηση
(C)
ethene
39
Which of the following is required in an experiment to determine the enthalpy of solution of anhydrous CuSO? l. Mass of the anhydrous CuSO 4 II. Volume of water in which the CuSO4 is dissolved lll. lnitial temperature of water lV. Final temperature of the solution
Απάντηση
(D)
l, ll, lll, and IV only
40
Which of the following pollutants is biodegradable?
