Trioxonitrate (V) acid is not used for preparing hydrogen gas from metals because it
Trả lời
(A)
is strongly oxidizing
2
An element used in the production of matches is
Trả lời
(D)
sulphur
3
When calcium oxide is heated with carbon, the oxide will
Trả lời
(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
Trả lời
(C)
trioxocarbonate (IV)
5
The soft solder used for welding and plumbing is alloy of
Trả lời
(A)
lead and tin
6
The reddish-brown rust on iron roofing sheets consists of
Trả lời
(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?
Trả lời
(C)
A decrease in the temperature and an incease in the concentration of the reactant
8
The tincture of iodine means iodine dissolved in
Trả lời
(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)?
Trả lời
(B)
more NH3(g)
10
Copper and silver metals are commonly used as coin because they are
Trả lời
(D)
not easily oxidized
11
Which of the following sets of metals dissolves in dilute HCl?
Trả lời
(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
Trả lời
(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
Trả lời
(C)
favour the reverse reaction
14
The reaction that takes place in Daniell's cell is
Trả lời
(B)
redox
15
What happens when zinc rod is immersed in copper (II) tetraoxosulphate (VI) solution?
Trả lời
(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
Trả lời
(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]
Trả lời
(B)
8 mins
18
Tartaric acid is used industrially to
Trả lời
(B)
make fruit juices
19
The salt formed from strong acid and a strong base is?
Trả lời
(B)
neutral
20
Dissolving some pellets of NaOH in water would result in
Trả lời
(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
Trả lời
(A)
0.015 mole
22
The oxidation state of oxygen in tetraoxosulphate (VI) acid is
Trả lời
(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
Trả lời
(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
Trả lời
(C)
3.55 g
25
Which experiment led to the measurement of the charge on an electron?
Trả lời
(B)
Oil-drop experiment
26
What is the volume of oxygen required to burn complete 45 cm\(^3\) of methane at s.t.p?
Trả lời
(D)
90.0 cm3
27
How many electrons are in the L shell of \(^{31}_{15}\)P?
Trả lời
(B)
8
28
If the electron configuration of an element is 1S\(^2\) 2S\(^2\)2P\(^5\), how many unpaired electron are there?
Trả lời
(C)
1
29
Which of the following decrease when a given mass of gas is compressed to half its initial volume?
Trả lời
(B)
Average intermolecular distance
30
The elements that belong to the third period of the periodic table are?
Trả lời
(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?
Trả lời
(A)
Ionic bonding
32
A mixture of petrol and water can be separated through
Trả lời
(C)
the use of separating funnel
33
Which of the following represents an aromatic compound?
