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