A mixture of sand, ammonium chloride and sodium chloride is best separated by?
إجابة
(A)
sublimation followed by addition of water and filteration
2
A pure solid usually melts?
إجابة
(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?
إجابة
(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)
إجابة
(B)
11.2 dm3
5
To what temperature must a gas 273 K be heated in order to double both its volume and pressure?
إجابة
(D)
1092 K
6
For a gas, the relative molecular mass is equal to 2Y. What is Y?
إجابة
(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?
إجابة
(C)
2.0
8
The shape of ammonia molecule is?
إجابة
(A)
trigonal planar
9
An increase in temperature causes an increase in the pressure of a gas because?
إجابة
(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?
إجابة
(D)
4
11
Which of the following physical properties decreases down a group in the periodic table?
إجابة
(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?
إجابة
(C)
XZ is electrovalent and YZ3 is covalent
13
A solid that absorbs water from he atmosphere and forms an aqueous solution is?
إجابة
(C)
deliquescent
14
A major effect of oil pollution in coastal waters is the?
إجابة
(A)
destruction of marine life
15
Sodium chloride has no solubility product value because of its?
إجابة
(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).
إجابة
(D)
2.00
17
Which of the following atoms represents deuterium?
إجابة
(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?
إجابة
(A)
less than 3.4
19
Which of the following compounds is a base?
إجابة
(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)
إجابة
(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)
إجابة
(D)
0.560 dm3
22
Crude copper could be purified by the electrolysis of concentrated copper (II) chloride if the crude copper is?
إجابة
(C)
made the anode
23
H- + H2(I)O → H2(g) + OH-(aq). From the equation above, it can be inferred that the?
إجابة
(B)
hydride ion is a reducing agent
24
An anhydride is an oxide of non-mental
إجابة
(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?
إجابة
(A)
+7 to +2
26
Which of the following is TRUE of Le Chatelier's Principle for an exothermic reaction?
إجابة
(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?
إجابة
(A)
N2O and steam
28
Which of these metals CANNOT replace hydrogen from alkaline solutions?
إجابة
(D)
Iron
29
Clothes should be properly rinsed with water after bleaching because?
إجابة
(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?
إجابة
(B)
Sodium tetraoxosulphate (IV)
31
SO3 is NOT directly dissolved in water in the preparation of H2SO4 by the contact process because?
إجابة
(A)
the reaction between SO3 and water is violently exothermic
32
In an electrolytic set-up to protect iron from corrosion, the iron is?
إجابة
(A)
made cathode
33
Which of the following is NOT true of metals?
إجابة
(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?
إجابة
(B)
Na> Ca> Al> Fe
35
Which of the following compounds is NOT an isomers of 2,2 dimethylbutane?
إجابة
(A)
2-methylbutane
36
When sodium is added to ethanol, the products are?
إجابة
(D)
sodium ethoxide and hydrogen
37
The general formula of alkanoates is?
إجابة
(D)
RCOOR
38
One mole of a hydrocarbon contains 48 g of carbon. If it vapour density is 28, the hydrocarbon is?
إجابة
(B)
an alkene
39
Which of the following reagents will confirm the presence of unsaturation in a compound?
إجابة
(B)
Bromine water
40
The diagram above represents an atom of
إجابة
(A)
magnesium
41
The set-up above would be useful for determining the amount of
إجابة
(B)
water vapour in air
42
The ∆H for the reaction represented by the energy profile above is
إجابة
(D)
-50 kJ mol-1
43
In the diagram above the activation energy is represented by
إجابة
(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?
إجابة
(D)
P
45
In the diagram above, R is a mixture of?
إجابة
(C)
potassium tetratoxomanganate (VII) and concentrated HCI
46
The IUPAC name of the compound above is
إجابة
(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?
إجابة
(C)
dehydration
48
MnO4(aq) + 8H + 5Fe2+ \(\to\) Mn2+(aq) + 5Fe3+(aq) + H2O. The oxidation number of maganese in the above reaction changed from
إجابة
(A)
+7 to +2
49
which of these metals CANNOT replace hydrogen from alkaline solutions?
إجابة
(D)
Iron
50
Clothes should be properly rinsed with water after bleaching because
إجابة
(D)
hydrogen chloride solution is produced during bleaching
