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