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?
Trả lời
(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.
Trả lời
(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.
Trả lời
(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?
Trả lời
(D)
lt is a halogen
6
Beryllium and aluminum have similar properties because they?
Trả lời
(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
Trả lời
(D)
ionic
8
How many protons, neutrons and electrons respectively are present in the element 60/27 Co?
Trả lời
(C)
27, 33, and 27
9
The radio active radiation used in studying the arrangement of particles in giant organic molecules is
Trả lời
(C)
X-rays
10
A silicon -containing ore has 92% 28Si, 5% 29Si and 3% 30Si. Calculate the relative atomic mass of the silicon.
Trả lời
(C)
28.11
11
Water is said to be temporarily hard when it contains
Trả lời
(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
Trả lời
(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]
Trả lời
(D)
0.50g
14
The dispersion of a liquid in a liquid medium will give
Trả lời
(A)
an emulsion
15
The major and most effective way of controlling pollution is to
Trả lời
(C)
educate people on the causes and effects of pollution
16
The basicity of CH3COOH is
Trả lời
(B)
1
17
The colour of litmus in a neutral medium is
Trả lời
(A)
purple
18
The mathematical expression of PH is
Trả lời
(B)
log 101/[H 3 O+]
19
Which of the following salts will turn blue litmus red?
Trả lời
(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
Trả lời
(B)
0 to + 2
21
\(H_2O_{(g)} + C_{(s)} → H_{2(g)} + CO_{(g)}\)
The oxidizing agent in the reaction above is
Trả lời
(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]
Trả lời
(B)
30156.3
23
How many faraday of electricity is required to produce 0.25 mole of copper?
Trả lời
(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.
Trả lời
(A)
+2081 Jmol-1
25
In an equilibrium reaction, which of the following conditions indicates that maximum yield of the product will be obtained?
Trả lời
(A)
Equilibrium constant is very large
26
In a chemical reaction, the change in concentration of a reactant with time is
Trả lời
(C)
rate of reaction
27
Fluorine does not occur in the free state in nature because
Trả lời
(D)
of its high reactivity
28
In the extraction of sodium from fused sodium chloride, the anode is made of platinum because
Trả lời
(D)
chlorine does not react with platinum
29
In the electrolytic extraction of calcium from calcium chloride, the cathode is
Trả lời
(D)
iron
30
A compound that gives a brick-red colour to a non-luminous flame is likely to contain
Trả lời
(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
Trả lời
(C)
Ca2+
32
The general formula of haloalkanes where X represents the halide is
Trả lời
(D)
C nH 2n+1X
33
The alkanol obtained from the production of soap is
Trả lời
(C)
glycerol
34
Ethyne is passed through a hot tube containing organo-nickel catalyst to produce
Trả lời
(D)
benzene
35
Due to the unstable nature of ethyne, it is stored by dissolving in
