Trioxonitrate (V) acid is not used for preparing hydrogen gas from metals because it
Răspuns
(A)
is strongly oxidizing
2
An element used in the production of matches is
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(D)
sulphur
3
When calcium oxide is heated with carbon, the oxide will
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(A)
be converted to carbide
4
A solution which on treatment with hydrochloric acid produces a colourless, odourless gas which turns lime water milky is most likely to be a
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(C)
trioxocarbonate (IV)
5
The soft solder used for welding and plumbing is alloy of
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(A)
lead and tin
6
The reddish-brown rust on iron roofing sheets consists of
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(C)
Fe2O3.3H2O
7
Na\(_2\)S\(_2\)O\(_3\)(aq) + 2HCl(aq) → 2NaCl(aq) + H\(_2\)O(l)
Which of the following would introduce the greatest increase in the rate of the chemical reaction above?
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(C)
A decrease in the temperature and an incease in the concentration of the reactant
8
The tincture of iodine means iodine dissolved in
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(A)
ethanol and water
9
Cu\(^{2+}\)(aq) + 4NH\(_3\)(g) ↔ [Cu(NH\(_3\))\(_4\)]\(^{2+}\)(aq)
In the reaction above, what is the effect of precipitating Cu\(^{2+}\)(aq) as CuS(s)?
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(B)
more NH3(g)
10
Copper and silver metals are commonly used as coin because they are
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(D)
not easily oxidized
11
Which of the following sets of metals dissolves in dilute HCl?
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(C)
Mg, Sn and Fe
12
If chlorine is bubbled into water and the resulting yellowish-green solution is exposed to bright sunlight for a while, the solution will decompose giving out
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(A)
oxygen and leaving behind aqueous hydrochloric acid
13
H\(_3\)PO\(_4\)(aq) + H\(_2\)O(l) ↔ H\(_2\)PO\(^{4-}\)(aq) + H\(_3\)O\(^+\)(aq) ΔH = -13kJ at 298K
In the reaction above, an increase in temperature would
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(C)
favour the reverse reaction
14
The reaction that takes place in Daniell's cell is
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(B)
redox
15
What happens when zinc rod is immersed in copper (II) tetraoxosulphate (VI) solution?
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(A)
The blue colour of the solution disappears
16
C\(_2\)H\(_4\)(g) + H\(_2\)(g) → C\(_2\)H\(_6\)(g) ΔH = -137kJ mol-1
The reaction represented above is
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(A)
exothermic
17
How long would it take to deposit 0.08g of copper from CuCl\(_2\) solution by passing a current of 0.5A?
[Cu = 64, 1F = 96500 C mol-1]
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(B)
8 mins
18
Tartaric acid is used industrially to
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(B)
make fruit juices
19
The salt formed from strong acid and a strong base is?
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(B)
neutral
20
Dissolving some pellets of NaOH in water would result in
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(D)
an increase in the entropy of the solution
21
Calculate the number of moles of HCl present in 20cm3 of a 0.75M solution of the acid
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(A)
0.015 mole
22
The oxidation state of oxygen in tetraoxosulphate (VI) acid is
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(B)
-2
23
MnO\(_2\)(s) + xHCl(aq) → MnCl\(_2\)(aq) + yH\(_2\)O(l) + zCl\(_2\)(g)
In the equation above, what are the values of x, y and z respectively
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(C)
4, 2, 1
24
Calculate the mass of chlorine gas which occupies a volume of 1.12dm3 at s.t.p
[Cl = 35.5, molar volume of gas at s.t.p = 22.4 dm3
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(C)
3.55 g
25
Which experiment led to the measurement of the charge on an electron?
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(B)
Oil-drop experiment
26
What is the volume of oxygen required to burn complete 45 cm\(^3\) of methane at s.t.p?
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(D)
90.0 cm3
27
How many electrons are in the L shell of \(^{31}_{15}\)P?
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(B)
8
28
If the electron configuration of an element is 1S\(^2\) 2S\(^2\)2P\(^5\), how many unpaired electron are there?
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(C)
1
29
Which of the following decrease when a given mass of gas is compressed to half its initial volume?
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(B)
Average intermolecular distance
30
The elements that belong to the third period of the periodic table are?
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(D)
Na, Mg, S and Ar
31
A metal X forms two bromides with the formulae XBr2 and XBr3. What type of bonding exists between X and bromine in the bromide?
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(A)
Ionic bonding
32
A mixture of petrol and water can be separated through
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(C)
the use of separating funnel
33
Which of the following represents an aromatic compound?
