Which of the following atoms contains the highest number of electrons in the outermost shell?
отговор
(B)
10Ne
2
What is the electronic configuration of an element represented as 199X?
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(A)
1s 22s2 2p 5
3
Pauli Exclusion Principle is related to
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(A)
quantum numbers of electrons
4
Which of the orbitals 4s, 4p, 4d and 4f has the lowest energy?
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(D)
4s
5
Two radioactive elements Q and S have half-life periods of 10 hours and 20 hours respectively. Therefore
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(D)
S is more stable than Q
6
Calcium atom ionizes by
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(B)
losing two electrons
7
Which of the following properties increases down a group in the Periodic Table?
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(A)
Atomic radius
8
In the Periodic Table, the elements that loss electrons most readily belong to
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(A)
Group 1 A
9
Which of the following reactions is not feasible?
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(B)
Cl2 + 2NaF → 2NaCI + F2
10
Which of the following halogens is the most reactive?
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(A)
F2
11
The crystal layers in graphite are held together by
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(B)
van der Waals' forces
12
Which of the following compounds has the highest ionic character?
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(D)
KCI
13
If an element with high electron affinity combines with another element with low ionization energy the bond formed will be mainly
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(B)
ionic
14
One mole of a compound M(HCO3)2 has a mass of 162g. Calculate the relative atomic mass of M. [H = 1, C =12, O = 16]
отговор
(D)
40
15
Exhaust fumes discharged from a smoky vehicle gradually become invisible as a result of
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(A)
diffusion
16
Which of the following movements can be described as random motion?
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(C)
Gas molecules colliding in a flask
17
Equal volumes of CO2 cnd CO at s.t.p have the same
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(D)
number of molecules
18
Gas molecules are said to be perfectly elastic because
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(A)
they collide without loss of energy
19
What volume of hydrogen is produced at s.t.p. When 2.60 g of zinc reacts with excess HCI according to the following equation? Zn(s) + 2HCI(aq) → ZnCI 2(aq) + H2(g) [Zn = 65; 1 mole of a gas occupies 22.4dm3 at s.t.p]
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(B)
0.896dm 3
20
Helium is preferred to hydrogen in filling balloons because hydrogen
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(A)
is inflammable
21
30cm3 pf hydrogen at s.t.p combine with 20cm3 of oxygen to form steam according to the following equation 2H2(g) + O2(g) → 2H2O(g).
Calculate the total volume of the gaseous mixture at the end of the reaction
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(B)
35cm3
22
An exothermic reaction is one which involves
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(B)
loss of heat to the surrounding
23
Which of the following is an acid salt?
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(D)
NaHCO3
24
Which of the following compounds dissolves in water to form a solution with pH below 7?
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(C)
Ammonium chloride
25
If the solubility of KHCO3 is 0.40 mole dm-3 at room temperature , calculate the mass of KHCO3 in 100dm3 of the solution at this temperature. [KHCO3 = 100hmol]
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(A)
4.0g
26
The property of calcium chloride which makes it useful as a drying agent is that it is
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(B)
deliquescent
27
Which of the following lowers the activation energy of a chemical reaction?
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(D)
Catalyst
28
Consider the reaction represented by the following equation: H2(g) + 12(g) → 2HI(g). The number of effective collisions of molecules of the reactants decreases as
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(C)
the volume of the system is increased
29
What will be the effect of increase in pressure on the following system at equilibrium? 2NH2(g) N2(g) + 3H2(g)
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(C)
the concentration of ammonia will increase
30
Which of the following is not correct about oxidation number convention? The oxidation number of a/an
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(D)
atom of a diatomic molecules is + 2
31
Equal volumes of water were added to one mole of each of the following compounds. Which of them produced the largest number of ions
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(B)
Sodium trioxonitrate (V)
32
When dilute copper (ll) chloride solution is electrolysed, the reaction at the cathode is represented by the equation
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(B)
Cu2+ + 2e- → Cu
33
How many carbon atoms are present in one molecule of 2-methylpropane?
отговор
(C)
4
34
Which of the following is the most reactive towards bromine?
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(C)
Ethyne
35
Which of the following compounds is unsaturated?
отговор
(C)
Methylbenzene
36
Which of the following compounds reacts with sodium hydroxide to form a salt?
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(A)
CH 3CH 2COOH
37
Alkanoates are produced from alkanols by
отговор
(D)
esterification
38
Which of the following is a secondary alkanol?
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(C)
CH 3-CH(OH)-CH 3
39
Geometric (cis-trans) isomerism is exhibited by
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(A)
C 2H 2CI 2
40
Which of the following is needed to produce slag during the extraction of iron in the blast furnace?
