When a solid substance disappears completely as a gas on heating, the substance is said to have undergone
Відповідь
(D)
sublimation
2
A chemical reaction is always associated with
Відповідь
(D)
the formation of new substance
3
If a solution contains 4.9g of tetraoxosulphate (VI) acid, calculate the amount of copper (II) oxide that will react with it
[Cu = 64, O = 16, S = 32, H = 1]
Відповідь
(B)
4.0g
4
What volume of gas is evolved at S.t.p if 2g of calcium trioxocarbonate (IV) is added to a solution of hydrochloric acid?
[Ca = 40, C = 12, O = 16, Cl = 35.5, H = 1 Molar volume of a gas at s.t.p = 22.4 dm\(^3\)
Відповідь
(C)
448 cm3
5
According to charles' law, the volume of a gas becomes zero at
Відповідь
(C)
-273 oC
6
It is difficult to achieve an orderly arrangement of the molecules of a gas because they?
Відповідь
(B)
have little force of attraction between them
7
A given volume of methane diffuses in 20s. How long will it take the same volume of sulphur (IV) oxide to diffuse under the same conditions?
[C = 12, H = 1, S = 32, O = 16
Відповідь
(C)
40s
8
An electron can be added to a halogen atom to form a halide ion with
Відповідь
(D)
8 valence electrons
9
The shape of s-orbitals is
Відповідь
(A)
spherical
10
\(^{226}\)\(_{88}\)Ra → \(^x\)\(_{86}\)Rn + α - particle
What is the value of x in the nuclear reaction above?
Відповідь
(B)
222
11
The property of chlorine which causes hydrogen chloride to be more ionic than the chlorine molecules is its
Відповідь
(D)
electronegativity
12
Chlorine consisting of two isotopes of mass number 35 and 37 in the ratio 3:1 has an atomic mass of 35.5. Calculate the relative abundance of the isotopes of mass number 37
Відповідь
(B)
25
13
Which of the following mixture of gases is likely to burn in flame?
Відповідь
(A)
neon and hydrogen
14
Hardness of water is caused by the presence of ions of
Відповідь
(B)
calcium and magnesium
15
Pollution of underground water by metal ions is very likely in the soil that has high
Відповідь
(A)
acidity
16
A carcinogenic substance is
Відповідь
(A)
asbestos dust
17
The solubility in moldm\(^{-3}\) of 20g of CuSO\(_4\) dissolved in 100g of water at 180\(^o\)C is
[Cu = 64, S = 32, O =16]
Відповідь
(C)
1.25
18
Calcium tetraoxosulphate (VI) dissolves in water only sparingly to form a
Відповідь
(C)
precipitate
19
Which of the following compound is a normal salt?
Відповідь
(D)
Na2CO3
20
What volume of 0.5 mol dm\(^{-3}\) H\(_2\)SO\(_4\) will exactly neutralize 20cm\(^3\) of 0.1 mol dm\(^{-3}\) NaOH solution?
Відповідь
(A)
2.0 cm3
21
The oxidation state of chlorine in HClO\(_4\) is
Відповідь
(D)
+7
22
ZnO(s) + CO(g) → Zn(s) + CO\(_2\)(g)
In the reaction above, Zinc has been
Відповідь
(D)
reduced
23
Which of the following acts as both reducing and oxidizing agent?
Відповідь
(B)
SO2
24
In the electrolysis of brine, the anode is
Відповідь
(D)
carbon
25
The mass of silver deposited when a current of 10A is passed through a solution of silver salt for 4830s is
[Ag = 108, 1F = 96500 Cmol-1]
Відповідь
(B)
54.0g
26
2CO(g) + O\(_2\)(g) → 2CO\(_2\)(g)
Given that ΔH[CO]is -110.4 kJmol-1 and ΔH[CO\(_2\)] is -393.0 kJmol-1, the energy change for the reaction above is
Відповідь
(B)
-282.6 kJ
27
Which of the following hydrogen halides has the highest entropy value?
Відповідь
(D)
HI
28
N\(_2\)O\(_4\),(g) ↔ 2NO\(_2\)(g)
In the endothermic reaction above, more product formation will be favoured by
Відповідь
(C)
a decrease in pressure
29
Which of the following shows little or no net reaction when the volume of the system is decreased?
Відповідь
(A)
H2(g) + I2(g) ↔ 2HI(g)
30
The allotrope of carbon used in the decolourization of sugar is
Відповідь
(C)
Charcoal
31
Which of the following gases can be collected by the method of downward delivery?
Відповідь
(A)
Chlorine
32
When steam is passed over red-hot carbon, the substances produced are
Відповідь
(C)
Hydrogen and carbon (II) oxide
33
Sulphur (IV) oxide bleaches by
Відповідь
(A)
Reduction
34
Carbon is tetravalent because
Відповідь
(C)
The 2s and 2p atomic orbitals hybridize
35
Aluminium hydroxide is used in the dyeing industry as a
Відповідь
(C)
Mordant
36
Alloys are best prepared by
Відповідь
(D)
Cooling a molten mixture of the metals
37
Transition metals possess variable oxidation states because they have
Відповідь
(A)
Electrons in the d orbitals
38
Sodium metal is always kept under oil because it
Відповідь
(C)
Reacts vigorously on exposure to air
39
Oxyacetylene flame is used for iron-welding because it
Відповідь
(C)
Evolves a lot of heat when burnt
40
The alkyl group can be represented by the general formula
Відповідь
(A)
CnH2n+1
41
An isomer of C\(_5\)H\(_{12}\) is
Відповідь
(B)
2 – methylbutane
42
A characteristic of the alkane family is
Відповідь
(C)
Substitution reaction
43
Which of these reagents can confirm the presence of a triple bond?
Відповідь
(A)
Bromine water
44
Vulcanization involves the removal of
Відповідь
(C)
the double bond
45
CH\(_3\)COOH(g) → CH\(_4\)(g) + CO\(_2\)(g)
The reaction above is
