If the relative molecular mass of an element is not a whole number, it can be deduced that the element is
คำตอบ
(D)
an isotopic mixture
2
The atomic number of chlorine is 17. What is the number of electrons in a chloride ion?
คำตอบ
(C)
18
3
Consider the following equation; Cr2O7(aq)2- + 14H+(aq) + 6e- → 2Cr3+(aq) + 7H2O(I). The oxidation number of chromium changes from
คำตอบ
(C)
+ 6 to + 3
4
Which of the following ions require the largest quantity of electricity for discharge at an electrode?
คำตอบ
(A)
2.0 mole of Q 3+
5
If two metallic ions of the same concentration migrate to a graphite cathode, the one that would be preferentially discharged is the one that has the
คำตอบ
(D)
stronger tendency to accept electrons
6
When concentrated sodium chloride solution is electrolysed using inert electrodes the products are?
คำตอบ
(D)
soduim hydroxide, hydrogen and chlorine
7
Which of the following processes takes place during the production of margarine from vegetable oils?
คำตอบ
(C)
Hydrogenation
8
Which of the following compounds can be represented by the molecular formula C2H6O?
คำตอบ
(B)
Ethanol
9
When alkynes are hydrogenated completely, they produce compounds with the general molecular formula
คำตอบ
(B)
C nH 2n+2
10
The following compounds are hydrocarbons except
คำตอบ
(A)
methylpropanoate
11
Which of the following statements about soapless detergents is correct? They
คำตอบ
(A)
lather readily with hard water
12
If the relative molecular mass of an element is not a whole number, it can be deduced that the element is
คำตอบ
(D)
an isotopic mixture
13
The atom of an element X is represented as \(^y_z X\). The basic chemical properties of X depend on the value of
คำตอบ
(B)
Z
14
The atomic number of chlorine is 17. What is the number of electrons in a chloride ion?
คำตอบ
(C)
18
15
A hydrogen atom which has lost an electron contains
คำตอบ
(A)
one proton only
16
Which of the following elements has a ground state electronic configuration with an incomplete penultimate shell?
คำตอบ
(A)
Iron
17
The conclusion from Rutherford's alpha-scattering experiment is that
คำตอบ
(A)
atoms are mostly empty space with a small nucleus
18
An element Y has the electronic configuration 1s22s22p6623p4. To what period does it belong in the periodic table?
คำตอบ
(A)
3
19
If a metal R forms a compound with the formula R(NO3)2 , the formula of its tetraoxosulphate (IV) is
คำตอบ
(B)
RSO4
20
Which of the following decreases when a given mass of gas is compressed to half its initial volume?
คำตอบ
(A)
Average intermolecular distance
21
What volume of hydrogen will be produced if 100cm3 of ammonia is completely decomposed at constant temperature and pressure? The equation for reaction is 2NH3(g) → N2(g) + 3H2(g)
คำตอบ
(B)
150cm3
22
Calculate the mass of chlorine gas which occupies a volume of 1.12 dm\(^3\) a volume of 1.12 dm\(^3\) at s.t.p [Cl = 35.5, 1 mole og gas occupies 22.4 dm\(^3\) at s. t. p ]
คำตอบ
(B)
3.55g
23
Determine the mass of sulphur (IV) oxide obtained when 91.0g of oxygen reacts completely with sulphur according to the following equation: S(s) + O\(_2\)(g) → SO\(_2\)(g) [S = 32; O = 16]
คำตอบ
(D)
182g
24
The gas given off when NH4 Cl is heated with an alkali is
คำตอบ
(D)
NH3
25
A major factor considered in selecting a suitable method for preparing a simple salt is its
คำตอบ
(D)
solubility in water
26
Which of following acids forms normal salts only?
คำตอบ
(C)
Acetic acid
27
A substance is said to be hygroscopic if it absorbs
คำตอบ
(D)
moisture from the atmosphere without dissolving
28
Which of the following substances increases in mass when heated in air?
คำตอบ
(C)
Magnesium ribbon
29
Calculate the mass of sodium hydroxide in 5.00 dm3 of a 0.125 mol dm-3 solution. [NaOH = 40 g mol-1]
คำตอบ
(D)
25.0 g
30
Which of the following salt solutions will have a pH greater than 7?
คำตอบ
(B)
Na2CO3(aq)
31
What will happen if more heat is applied to the following system at equilibrium?
What is the expression for the equilibrium constant (Kc) for the following reaction? N2(g) + O2(g) ⇌ 2NO(g)
คำตอบ
(D)
\(\frac{[NO]^2}{[N_2][O^2]}\)
33
Equal amounts of marble chips are reacted separately with 100cm3 of hydrochloric acid of different concentrations. If all the marble chips reacted; which of the following remained the same in each case?
คำตอบ
(B)
Total mass of gas evolved during the reaction
34
CuSO45H2O can be obtained from an aqueous solution of copper (ll) tetraoxosulphate (VI) by
คำตอบ
(D)
crystallization
35
Which of the following compounds will leave a metal residue when heated?
คำตอบ
(B)
AgNO3
36
A visible change is observed when a strip of iron is placed in an aqueous solution of
คำตอบ
(C)
CuSO4
37
Consider the following equation: Cr\(_2\)O\(_7\)\(^{2-}\)(aq) + 14H\(^+\)(aq) + 6e\(^-\) → 2Cr\(^{3+}\)(ag) + 7H\(_2\)O(1). The oxidation number of chromium changes from
คำตอบ
(C)
+6 to +3
38
Which of the following ions require the largest quantity of electricity for discharge at an electrode?
คำตอบ
(A)
2.0 mole of Q 3+
39
If two metallic ions of the same concentration migrate to a graphite cathode, the one that would be preferentially discharged is the one that has the
คำตอบ
(D)
stronger tendency to accept electrons
40
When concentrated sodium chloride solution is electrolysed using inert electrodes, the products are
คำตอบ
(B)
hydrogen and chlorine
41
Which of the following processes takes place during the production of margarine from vegetable oils?
คำตอบ
(C)
Hydrogenation
42
Which of the following compounds can be represented by the molecular formula C2H6O?
คำตอบ
(B)
Ethanol
43
When alkynes are hydrogenated completely they produce compounds with the general molecular formula
คำตอบ
(C)
CnH2n+2
44
The following compounds are hydrocarbons except
คำตอบ
(A)
methylpropanoate
45
The reaction between ethene and chlorine to form 1, 2-dichloroethane is
คำตอบ
(C)
addition
46
Which of the following statements about soapless detergents is correct? They
คำตอบ
(A)
lather readily with hard water
47
Which of the following types of alkanols undergo oxidation to produce alkanoic acids? I. Primary alkanols II. Secondary alkanols III. Tertiary alkanols
คำตอบ
(D)
l only
48
A suitable reagent for distinguishing between ethanoic acid ethanol is
