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