200cm\(^3\) each of 0.1M solutions of lead (II) trioxonitrate(V) and hydrochloric acid were mixed. Assuming that lead (II) chloride is completely insoluble, calculate the mass of lead (II) chloride that will be precipitated.
[Pb = 207, Cl= 35.5, N = 14, O = 16]
отговор
(A)
2.78g
2
56.00cm3 of a gas at S.T.P. weighed 0.11g. What is the vapour density of the gas?
[Molar volume of a gas at S.T.P = 22.4dm3]
отговор
(B)
22.00
3
Which of the following gases will diffuse fastest when passed through a porous plug?
[H = 1, C = 12, N = 14, O = 16]
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(C)
Methane
4
Which is the temperature of a given mass of a gas initially at 0°C and 9 atm, if the pressure is reduced to 3 atm at constant volume?
отговор
(A)
91K
5
Which of the following will have its mass increased when heated in air?
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(B)
Magnesium
6
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
From the equation above, the mass of magnesium required to react with 250cm3 of 0.5M HCl is
[Mg = 24]
отговор
(B)
1.5g
7
A gaseous metallic chloride MClx consists of 20.22% of M by mass. The formula of the chloride is?
[M = 27, Cl = 35.5]
отговор
(C)
MCl3
8
In which of the following are water molecules in the most disorderly arrangement?
отговор
(D)
Steam at 100°C
9
In order to remove one electron from a 3S orbital of gaseous sodium atom, about 496KJMol-1 of energy is required. This energy is referred to as
отговор
(B)
ionization energy
10
Nitrogen obtained from the liquefaction of air has a higher density than that obtained from nitrogen containing compounds because the former contains
отговор
(D)
rare gases
11
The method that can be used to convert hard water to soft water is
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(C)
the use of an ion-exchange resin
12
1s2, 2s2, 2p6, 3s2, 3p6, 3d7, 4s2
An element with the electronic configuration above is a
отговор
(C)
transition element
13
Given that electronegativity increases across a period and decreases down a group in the periodic table, in which of the following compounds will the molecules be held together by the strongest hydrogen bond?
отговор
(A)
HF(g)
14
0.25 mole of hydrogen chloride was dissolved in distilled water and the volume made up of 0.50 dm3. If 15.0 cm3 of the solution requires 12.50 cm3 of aqueous sodium trioxocarbonate (IV) for neutralization, calculate the concentration of the alkaline solution
отговор
(A)
0.30 mol dm3
15
The correct order of increasing oxidation number of the transition metal ions for the compounds K2Cr2O7, V2O5 and KMnO4 is
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(A)
V2O5 < K2Cr2O7 < KMnO4
16
The set of pollutants that is most likely to be produced when petrol is accidentally spilled on plastic materials and ignited is
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(B)
CO, HCL and SO2
17
What is observed when aqueous solutions of each of tetraoxosulphate (VI) acid, potassium trioxoiodate (V) and potassium iodide are mixed together?
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(D)
The mixture turns reddish brown
18
The solution with the lowest pH value is
отговор
(C)
15 ml of (m/5) HCl
19
The solubility product of Cu(IO3)2 is 1.08 * 10-7. Assuming that neither ions react appreciable with water to form H+ and OH-, what is the solubility of this salt?
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(C)
3.0 * 10-3 mol dm-3
20
The entropy and enthalpy of a system are a measure of
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(A)
degree of disorderlinesss and heat content respectively
21
2SO2(g) + O2(g) ↔ 2SO3(g). In the chemical reaction above, the substance that will increase the rate of production of sulphur (VI) oxide is
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(C)
vanadium (V) oxide
22
N\(_2\)O\(_4\)(g) ↔ 2NO\(_2\)(g). Increase in total pressure of the equilibrium reaction above will
отговор
(D)
produce more of N2O4(g) in the mixture
23
What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?
[ F = 96 5000 C mol-1 ]
отговор
(B)
48 250 coulombs
24
X + Y → Z. The rate equation for the chemical reaction above is \(\frac{-Δx}{Δt}\) = K[X]\(^2\)[Y].
The overall order of the reaction is?
отговор
(D)
3.0
25
When a current I was passed through an electrolyte solution for 40 minutes, a mass X g of a univalent metal was deposited at the cathode. What mass of the metal will be deposited when a current 2I is passed through the solution for 10 minutes?
отговор
(B)
X/2 g
26
RS(aq) + HF(aq) → RF(s) + HS(aq)
ΔH = -65.7 kj mol(-1).
From the equation above, it can be deduced that
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(B)
the heat content of the reactants is higher than that of the products
27
Which of the following statement is true of the electrochemical series?
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(D)
Electropositivity of metals decreases down the series
28
The gas that will form a white precipitate with acidified silver trioxonitrate (v) is
отговор
(D)
HCL
29
Chlorine, bromine and iodine resemble one another in that they?
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(A)
dissolve in alkalis
30
The salt that reacts with dilute hydrochloric acid to produce a pungent smelling gas which decolourizes acidified purple potassium tetraoxomanganate (VII) solution is
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(B)
Na2SO3
31
A pair of compounds that can be used to generate a gas which has physiological effect on human beings is
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(C)
sodium trioxonitrate (V) and ammonium chloride
32
Hydrogen is used in oxy-hydrogen flames for melting metals because it
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(A)
evolves a lot of heat when burnt
33
What properties of duralumin make it more useful than its constituent metals?
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(C)
It is strong and light
34
The pair of metals in the reactivity series that are usually extracted by the electrolysis of their ores is
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(B)
magnesium and calcium
35
A metal that can be extracted from cassitertite is
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(C)
tin
36
Which of the following metals is passive to concentrated trioxonitrate (V) acid?
отговор
(A)
Iron
37
The hydrocarbon that burns in air with a sooty flames is
отговор
(D)
C6H6
38
2-methylprop-1-ene is an isomer of
отговор
(A)
but-2-ene
39
Which of the following is a solvent for perfumes?
отговор
(D)
C2H5OH
40
When excess ethanol is heated to 145oC in the presence of concentrated H2SO4, the product is
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(C)
diethyl ether
41
POlyvinyl chloride is used to produce
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(D)
pipes
42
An organic compound that does not undergo a reaction with both hydrogen cyanide and hydroxylamine can be
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(A)
alkene
43
When the two end alkyl groups ethyl ethanoate are interchange, the compound formed is known as
отговор
(C)
methyl propanoate
44
From the diagram above the mass of crystals deposited when 1 dm 3 of a saturated solution of NaCl is cooled from 80 oC to 60oC is
[Na = 23, Cl = 35.5]
