The electronic configuration of an element is 1\(s^2\) 2\(s^2\) 2\(p^6\) 3\(s^2\) 3\(p^3\). Where is the element located in the periodic table?
คำตอบ
(C)
Group V, period 3
2
Group O of elements are unreactive because
คำตอบ
(B)
their highest occupied enegy level is full
3
An element X with electronic configuration \(1S^22S^22P^63S^2\) combines with another element Y with the configuration \(1S^2S^22P^23S^23P^5\). What is the formula of the compound formed?
คำตอบ
(D)
XY2
4
Which of the following statements about dative bonding is not correct?
คำตอบ
(C)
each participating atom contributes one electron
5
Which of the following quantities is the same for one mole of Br2(l) and one mole of He(g)?
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(A)
Number of molecules
6
Which of the following acids is dibasic?
คำตอบ
(B)
Trioxosulphate (IV) acid
7
Bees inject an acidic substance when they sting. Which of the following chemical could be used to treat bee stings?
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(B)
NaHCO3
8
Which of the following salts can be prepared by reacting the metal with dilute H2SO4?
คำตอบ
(B)
MgSO4
9
Which of the following solutions will give a precipitate with dilute tetraoxosulphate (V) acid? l. Lead (ll) trioxonitrate (V) solution ll. Barium chloride solution lll. Sodium chloride solution
คำตอบ
(C)
l and ll only
10
Substance Q reacts with cold water to form a solution which turns red litmus blue. Substance Q could be
คำตอบ
(D)
sodium
11
What term is used to describe an oxide whose aqueous solution turns blue litmus red?
คำตอบ
(B)
Acid anhydride
12
The pH of 0.50 mol dm-3 solutions of HCI, H2SO4 and CH3COOH were measured. which of the following statements about the values obtained is correct?
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(D)
the pH value of the CH3COOH was the highest.
13
Which of the following processes involves neutralization?
คำตอบ
(D)
Liming of soil
14
Sea shells contain mainly CaCO 3. Calcium oxide can be prepared from sea shells by
คำตอบ
(B)
heating at a high temperature
15
Which of the following statements about an exothermic reaction is correct?
คำตอบ
(A)
the products have less heat content than reactants
16
A reducing agent is expected to
คำตอบ
(A)
decolourize acidified KMnO4 solution
17
Consider the electrochemical cell represented below Zn(s)/Zn2+(aq)//Cu2+(aq)/Cu(s). Which of the following equations describes the reaction occurring in the cell?
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(C)
Zn(s) + Cu2+(aq) →Zn2+(aq) + Cu(s)
18
Five metals represented by the letters V to Z are arranged in order of their reactivity as shown . V>W>X>Y>Z.
Which of the metals cannot displace Y from an aqueous solution of its salt?
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(D)
Z
19
Five metals represented by the letters V to Z are arranged in order of their reactivity as shown . V>W>X>Y>Z.
Which of the metals is most likely extracted by the electrolysis of its fused chloride?
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(A)
V
20
Which of the following statements is/are correct about tin plating? l The electrolyte must be a soluble salt of tin ll. the objective to be plated is made the cathode lll. The anode is made of tin lV. The negative electrode dissolves
คำตอบ
(C)
l,ll and lll only
21
Determine the amount of electrons needed to deposit 6.4g of copper during the electrolysis of copper (ll) tetraoxosulphate (IV) solution [Cu = 64]
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(B)
0.20 mole
22
A given fuel has an octane number of 100. This means that
คำตอบ
(A)
the knocking tendency of the fuel is low
23
The equation for the reaction at the anode during the electrolysis of concentrated sodium chloride solution is
คำตอบ
(A)
2CI-(aq) → CI,sub>2(g) + 2e-
24
Which of the following compounds has the same empirical formula as benzene?
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(A)
C2H2
25
A given fuel has an octane number of 100. This means that
คำตอบ
(A)
the knocking tendency of the fuel is low
26
Wine containing 8% to 17% ethanol can be converted to gin containing about 40% ethanol by
คำตอบ
(B)
distilation
27
Which of the following substances could be responsible for the banana taste of a food flavour?
คำตอบ
(D)
Pentylethanoate
28
What is the organic product of the reaction of C2H 5OH with excess acidified K 2Cr 2O7(aq)?
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(A)
CH3COOH
29
The reaction of vegetable oil with a solution of wood ash is
คำตอบ
(A)
saponification
30
What process does the following equation represent ? n(C\(_{6}\)H\(_{10}\)O\(_{5}\)) + nH\(_{2}\)O → nC\(_{6}\)H\(_{12}\)O\(_{6}\) ?
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(B)
Hydrolysis of starch
31
When excess ethene is shaken with acidified KMnO4 solution, the product obtained is
คำตอบ
(C)
ethane - 1, 2 - diol
32
What volume of 0.20 mol dm -3 NaOH solution would yield 5.0 g of NaOH on evaporation to dryness? [NaOH = 40g mol-1]
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(B)
625 cm3
33
Which of the following compound is used for removing impurities from bauxite?
คำตอบ
(A)
NaOH
34
What is the main impurity in haematite?
คำตอบ
(C)
SiO3
35
When a sample of water was boiled, it lathered more readily with soap. it can be concluded that the sample most likely contained
