A mixture of sand, ammonium chloride and sodium chloride is best separated by?
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(A)
sublimation followed by addition of water and filteration
2
A pure solid usually melts?
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(B)
over a narrow range of temperature
3
At the same temperature and pressure, 50 cm3 of nitrogen gas contains the same number of molecules as?
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(C)
50 cm3 of ammonia
4
8g CH4 occupies 11.2 dm3 at s.t.p. What volume would 22 g of CH3CH2CH3 occupy under the same condition?
(C = 12, H = 1)
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(B)
11.2 dm3
5
To what temperature must a gas 273 K be heated in order to double both its volume and pressure?
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(D)
1092 K
6
For a gas, the relative molecular mass is equal to 2Y. What is Y?
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(B)
The vapour density of the gas
7
The densities of two gases, X and Y, are 0.5 g dm-3 and 2.0 dm-3 respectively.
What is the rate of diffusion of X relative to Y?
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(C)
2.0
8
The shape of ammonia molecule is?
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(A)
trigonal planar
9
An increase in temperature causes an increase in the pressure of a gas because?
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(B)
the molecules of the gas bombard the walls of the container more frequently
10
The number of electrons in the valence shell of an element of atomic number 14 is?
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(D)
4
11
Which of the following physical properties decreases down a group in the periodic table?
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(D)
Electronegativity
12
Element X, Y and Z belong to a groups I, V and VII respectively. Which of the following is TRUE about the bond types of XZ and YZ3?
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(C)
XZ is electrovalent and YZ3 is covalent
13
A solid that absorbs water from he atmosphere and forms an aqueous solution is?
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(C)
deliquescent
14
A major effect of oil pollution in coastal waters is the?
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(A)
destruction of marine life
15
Sodium chloride has no solubility product value because of its?
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(B)
high solubility
16
The solubility, in moles per dm3 of 20.2 g of potassium trioxonitrate (V) dissolve in 100 g of the resulting mixture is?
(K = 39, O = 16, N =14).
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(D)
2.00
17
Which of the following atoms represents deuterium?
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(C)
No protons = 1, No of neutrons = 1, No of electrons = 1
18
A few drops of concentrated HCI are added to about 10cm3 of a solution of pH 3.4. The pH of the resulting mixtures is?
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(A)
less than 3.4
19
Which of the following compounds is a base?
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(B)
CaO
20
20 cm\(^3\) of a 2.0 M solution of ethanoic acid was added to excess of 0.05 M sodium hydroxide. The mass of the salt produced is?
(Na = 23, C = 12, O = 16, H = 1)
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(C)
3.28 g
21
What volume of Oxygen measured at s.t.p would be liberated on electrolysis by 9650 coulombs of electricity?
(Molar volume of gas = 22.4 dm\(^3\), 1F = 96,500 C/mol)
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(D)
0.560 dm3
22
Crude copper could be purified by the electrolysis of concentrated copper (II) chloride if the crude copper is?
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(C)
made the anode
23
H- + H2(I)O → H2(g) + OH-(aq). From the equation above, it can be inferred that the?
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(B)
hydride ion is a reducing agent
24
An anhydride is an oxide of non-mental
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(C)
whose solution in water has a pH less than 7
25
MnO4(aq) + 8H + (aq) + 5Fe2+ → Mn2+(aq) + 4H2O(I). The oxidation number of manganese in the above reaction changed from?
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(A)
+7 to +2
26
Which of the following is TRUE of Le Chatelier's Principle for an exothermic reaction?
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(B)
Increase in temperature will cause a decrease in the equilibrium constant
27
Which of the following are produced when ammonium trioxonitrate (V) crystals are cautiously heated in a hard glass round bottomed flask?
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(A)
N2O and steam
28
Which of these metals CANNOT replace hydrogen from alkaline solutions?
Одговорити
(D)
Iron
29
Clothes should be properly rinsed with water after bleaching because?
Одговорити
(D)
hydrogen chloride solution is produced during bleaching
30
Which of these solutions will give a white precipitate with a solution of barium chloride acidified with hydrochloric acid?
Одговорити
(B)
Sodium tetraoxosulphate (IV)
31
SO3 is NOT directly dissolved in water in the preparation of H2SO4 by the contact process because?
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(A)
the reaction between SO3 and water is violently exothermic
32
In an electrolytic set-up to protect iron from corrosion, the iron is?
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(A)
made cathode
33
Which of the following is NOT true of metals?
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(C)
Their oxides are acidic
34
Which of the following is the correct order of decreasing activity of the metals Fe, Ca, Al and Na?
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(B)
Na> Ca> Al> Fe
35
Which of the following compounds is NOT an isomers of 2,2 dimethylbutane?
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(A)
2-methylbutane
36
When sodium is added to ethanol, the products are?
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(D)
sodium ethoxide and hydrogen
37
The general formula of alkanoates is?
Одговорити
(D)
RCOOR
38
One mole of a hydrocarbon contains 48 g of carbon. If it vapour density is 28, the hydrocarbon is?
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(B)
an alkene
39
Which of the following reagents will confirm the presence of unsaturation in a compound?
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(B)
Bromine water
40
The diagram above represents an atom of
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(A)
magnesium
41
The set-up above would be useful for determining the amount of
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(B)
water vapour in air
42
The ∆H for the reaction represented by the energy profile above is
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(D)
-50 kJ mol-1
43
In the diagram above the activation energy is represented by
Одговорити
(A)
y - x
44
2HCL(ag) + CaCO3(ag) → CaCL2(ag) + H2O(1) + CO from the reaction above, which of the following curves represents the consumption of calcium trioxocarbonate (IV) as dilute HCL is added to it?
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(D)
P
45
In the diagram above, R is a mixture of?
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(C)
potassium tetratoxomanganate (VII) and concentrated HCI
46
The IUPAC name of the compound above is
Одговорити
(C)
3,3-dimethyl but -1-ene
47
Use the diagram above to answer this question. The reaction taking place in flask G is known as?
Одговорити
(C)
dehydration
48
MnO4(aq) + 8H + 5Fe2+ \(\to\) Mn2+(aq) + 5Fe3+(aq) + H2O. The oxidation number of maganese in the above reaction changed from
Одговорити
(A)
+7 to +2
49
which of these metals CANNOT replace hydrogen from alkaline solutions?
Одговорити
(D)
Iron
50
Clothes should be properly rinsed with water after bleaching because
Одговорити
(D)
hydrogen chloride solution is produced during bleaching
