the constituent of a compound are chemically bound together while those of a mixture are not
2
What is the percentage of sulphur in sulphur (IV) oxide?
отговор
(D)
50%
3
A gas X diffuses twice as fast as gas Y. if the relative molecular mass of X is 32, calculate the relative molecular mass of Y.
отговор
(A)
128
4
200 cm3 of a gas at 25ºC exerts a pressure of 700 mmHg. Calculate its pressure if its volume increase 350 cm3 at 75ºC.
отговор
(C)
467.11 mmHg
5
An element X has electron configuration 1s2 2s2 2p6 3s2 3p5. Which of the following statements is correct about the element?
отговор
(D)
lt is a halogen
6
Beryllium and aluminum have similar properties because they?
отговор
(D)
are positioned diagonally to each other
7
If the difference in electronegativity of elements P and Q is 3.0. The bond that will be formed between them is
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(D)
ionic
8
How many protons, neutrons and electrons respectively are present in the element 60/27 Co?
отговор
(C)
27, 33, and 27
9
The radio active radiation used in studying the arrangement of particles in giant organic molecules is
отговор
(C)
X-rays
10
A silicon -containing ore has 92% 28Si, 5% 29Si and 3% 30Si. Calculate the relative atomic mass of the silicon.
отговор
(C)
28.11
11
Water is said to be temporarily hard when it contains
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(A)
Ca (HCO3)2 and Mg (HCO3)2 salts
12
On exposure to the atmosphere, a hydrated salt loses its water of crystallization to become anhydrous. This phenomenon is referred to as
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(A)
efflorescence
13
16.55g of lead (ll) trioxonitrate (V) was dissolved in 100g of distilled water at 20oC, calculate the solubility of the solute in moldm-3
[Pb = 207, N = 14, O = 16]
отговор
(D)
0.50g
14
The dispersion of a liquid in a liquid medium will give
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(A)
an emulsion
15
The major and most effective way of controlling pollution is to
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(C)
educate people on the causes and effects of pollution
16
The basicity of CH3COOH is
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(B)
1
17
The colour of litmus in a neutral medium is
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(A)
purple
18
The mathematical expression of PH is
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(B)
log 101/[H 3 O+]
19
Which of the following salts will turn blue litmus red?
отговор
(B)
Sodium hydrogentetraoxosulphate (VI)
20
Zn (s) + CuSO 4(aq) → ZnSO 4(aq) + Cu (s)
In the reaction above, the oxidation number of the reducing agent changes from
отговор
(B)
0 to + 2
21
\(H_2O_{(g)} + C_{(s)} → H_{2(g)} + CO_{(g)}\)
The oxidizing agent in the reaction above is
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(C)
H2O(g)
22
Calculate the quantity of electricity in coulombs required to liberate 10g of copper from a copper compound
[Cu=64, F = 96500 Cmol-1]
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(B)
30156.3
23
How many faraday of electricity is required to produce 0.25 mole of copper?
отговор
(D)
0.50F
24
If the change in free energy of a system is -899 Jmol-1 and the entropy change is 10Jmol-1k-1 at 250C, calculate the enthalpy change.
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(A)
+2081 Jmol-1
25
In an equilibrium reaction, which of the following conditions indicates that maximum yield of the product will be obtained?
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(A)
Equilibrium constant is very large
26
In a chemical reaction, the change in concentration of a reactant with time is
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(C)
rate of reaction
27
Fluorine does not occur in the free state in nature because
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(D)
of its high reactivity
28
In the extraction of sodium from fused sodium chloride, the anode is made of platinum because
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(D)
chlorine does not react with platinum
29
In the electrolytic extraction of calcium from calcium chloride, the cathode is
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(D)
iron
30
A compound that gives a brick-red colour to a non-luminous flame is likely to contain
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(C)
calcium ions
31
A few drops of NaOH solution was added to an unknown salt forming a white precipitate which is insoluble in excess solution. The cation likely present is
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(C)
Ca2+
32
The general formula of haloalkanes where X represents the halide is
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(D)
C nH 2n+1X
33
The alkanol obtained from the production of soap is
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(C)
glycerol
34
Ethyne is passed through a hot tube containing organo-nickel catalyst to produce
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(D)
benzene
35
Due to the unstable nature of ethyne, it is stored by dissolving in
