When a solid substance disappears completely as a gas on heating, the substance is said to have undergone
Răspuns
(D)
sublimation
2
A chemical reaction is always associated with
Răspuns
(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]
Răspuns
(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\(^3\)
Răspuns
(C)
448 cm3
5
According to charles' law, the volume of a gas becomes zero at
Răspuns
(C)
-273 oC
6
It is difficult to achieve an orderly arrangement of the molecules of a gas because they?
Răspuns
(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
Răspuns
(C)
40s
8
An electron can be added to a halogen atom to form a halide ion with
Răspuns
(D)
8 valence electrons
9
The shape of s-orbitals is
Răspuns
(A)
spherical
10
\(^{226}\)\(_{88}\)Ra → \(^x\)\(_{86}\)Rn + α - particle
What is the value of x in the nuclear reaction above?
Răspuns
(B)
222
11
The property of chlorine which causes hydrogen chloride to be more ionic than the chlorine molecules is its
Răspuns
(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
Răspuns
(B)
25
13
Which of the following mixture of gases is likely to burn in flame?
Răspuns
(A)
neon and hydrogen
14
Hardness of water is caused by the presence of ions of
Răspuns
(B)
calcium and magnesium
15
Pollution of underground water by metal ions is very likely in the soil that has high
Răspuns
(A)
acidity
16
A carcinogenic substance is
Răspuns
(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]
Răspuns
(C)
1.25
18
Calcium tetraoxosulphate (VI) dissolves in water only sparingly to form a
Răspuns
(C)
precipitate
19
Which of the following compound is a normal salt?
Răspuns
(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?
Răspuns
(A)
2.0 cm3
21
The oxidation state of chlorine in HClO\(_4\) is
Răspuns
(D)
+7
22
ZnO(s) + CO(g) → Zn(s) + CO\(_2\)(g)
In the reaction above, Zinc has been
Răspuns
(D)
reduced
23
Which of the following acts as both reducing and oxidizing agent?
Răspuns
(B)
SO2
24
In the electrolysis of brine, the anode is
Răspuns
(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]
Răspuns
(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
Răspuns
(B)
-282.6 kJ
27
Which of the following hydrogen halides has the highest entropy value?
Răspuns
(D)
HI
28
N\(_2\)O\(_4\),(g) ↔ 2NO\(_2\)(g)
In the endothermic reaction above, more product formation will be favoured by
Răspuns
(C)
a decrease in pressure
29
Which of the following shows little or no net reaction when the volume of the system is decreased?
Răspuns
(A)
H2(g) + I2(g) ↔ 2HI(g)
30
The allotrope of carbon used in the decolourization of sugar is
Răspuns
(C)
Charcoal
31
Which of the following gases can be collected by the method of downward delivery?
Răspuns
(A)
Chlorine
32
When steam is passed over red-hot carbon, the substances produced are
Răspuns
(C)
Hydrogen and carbon (II) oxide
33
Sulphur (IV) oxide bleaches by
Răspuns
(A)
Reduction
34
Carbon is tetravalent because
Răspuns
(C)
The 2s and 2p atomic orbitals hybridize
35
Aluminium hydroxide is used in the dyeing industry as a
Răspuns
(C)
Mordant
36
Alloys are best prepared by
Răspuns
(D)
Cooling a molten mixture of the metals
37
Transition metals possess variable oxidation states because they have
Răspuns
(A)
Electrons in the d orbitals
38
Sodium metal is always kept under oil because it
Răspuns
(C)
Reacts vigorously on exposure to air
39
Oxyacetylene flame is used for iron-welding because it
Răspuns
(C)
Evolves a lot of heat when burnt
40
The alkyl group can be represented by the general formula
Răspuns
(A)
CnH2n+1
41
An isomer of C\(_5\)H\(_{12}\) is
Răspuns
(B)
2 – methylbutane
42
A characteristic of the alkane family is
Răspuns
(C)
Substitution reaction
43
Which of these reagents can confirm the presence of a triple bond?
Răspuns
(A)
Bromine water
44
Vulcanization involves the removal of
Răspuns
(C)
the double bond
45
CH\(_3\)COOH(g) → CH\(_4\)(g) + CO\(_2\)(g)
The reaction above is
