The crystal layers in graphite are held together by
คำตอบ
(D)
van der Waal's forces
3
Hydrogen bonds are formed between molecules containing a hydrogen atom bonded to a
คำตอบ
(A)
strongly electronegative atom
4
The two elements 11X and 19Y are in the same group because they have the same
คำตอบ
(A)
valence electrons
5
Which of the following arrangements is in decreasing order of atomic radius?
คำตอบ
(C)
Li>Be>B>C
6
Which of the following processes is used in food preservation in an industry?
คำตอบ
(B)
Ieeadiation of gamma rays
7
The electron configuration of \(_{26}Fe^{3+}\) is?
คำตอบ
(D)
[AR]4s03d5
8
Which of the following transition metals is not attracted to external magnetic field?
คำตอบ
(A)
Cu
9
An atom W has 17 electrons and 18 neutrons. Which of the following representations of the atom is correct?
คำตอบ
(C)
3517W
10
The relative atomic mass of chlorine is not a whole number because
คำตอบ
(B)
it is the average mass of all the isotopes of the element
11
NH4- is formed from NH3 and H- by
คำตอบ
(B)
dative bonding
12
How many lone pair (s) of electrons is present in HF?
คำตอบ
(D)
3
13
An aqueous solution of Na2CO3 is
คำตอบ
(B)
alkaline
14
A gaseous mixture contains 0,256 g of hydrogen and 2.00 g of oxygen. The mole ration of hydrogen to oxygen in the mixture is (H=1.00; O=16,0)
คำตอบ
(B)
2:1
15
The oxidation number of sulphur in Fe2(SO4)3 is
คำตอบ
(D)
+6.
16
If 0.20 mol dm-3 NaOH(aq) was evaporated to yield 5.0g of solid NaOH, calculate the volume of NaOH (aq) used. (Na = 23.0,O = 16:0; H = 1.00)
คำตอบ
(B)
625cm3
17
The mass of 800cm3 of gas Q at s.t.p. is 1.0g. What is the molar mass of Q? [Avogadros constant = 22.4dm3 mol-1`]
คำตอบ
(C)
28.0gmol-1
18
Which of the following statements about a chemical system in equilibrium is correct/ The
คำตอบ
(C)
equilibrium is re-established when a stress is applied
19
Which of the following relationships correctly expresses the Boyle's law?
คำตอบ
(C)
P \(\alpha\) \(\frac{1}{V}\) at constant T
20
The vapour pressure of a given volume of liquid increase when the
คำตอบ
(D)
temperature of the Liquid rises
21
Which of the following statements about volatile liquids is correct? They have
คำตอบ
(A)
high vapour pressure and low boiling point
22
The type of energy changes that accompany the mixing of a strong acid to a strong base is
คำตอบ
(B)
heat
23
Zinc oxide is said to be amphoteric because it
คำตอบ
(D)
reacts with a base or an acid
24
Which of the following substances with the corresponding pH value is an alkali?
Substance pH
คำตอบ
(D)
Milk of magnesia 10.5
25
The gases produced when Cu(NO3)2(s) was heated are
คำตอบ
(B)
O2 and NO
26
Which of the following salts on hydrolysis would give an alkaline solution?
คำตอบ
(C)
CH3COONa(s)
27
Consider the reaction represented by the following equation: Na2CO3(aq) + 2HCl(aq) \(\longrightarrow\) 2NaCl(aq) + H2O(l) + CO2(g) . What volume of 0.02 mol dm-3 Na2CO3(aq) would be required to completely neutralize 40 cm3 of 0.10 mol dm-3 HCl(aq)?
คำตอบ
(B)
100 cm3
28
Which of the following factors would affect the equilibrium constant?
คำตอบ
(B)
Temperature
29
Consider the reaction represented by the following equation: N2(g) + 3H2(g) ⇌ 2NH3(g); ∆Hϴ = -xkJ mol-1. Which of the following conditions would increase the yield of NH3?
คำตอบ
(D)
Increase in the total pressure of the system
30
The reaction that occurs all the anode when CuSO4(aq) is electrolyzed using carbon electrode is
คำตอบ
(C)
4OH (aq)-4e → 2H2O(l) + O2 (g)
31
Reduction is the process of
คำตอบ
(C)
loss of oxygen
32
Ethene molecules can be added to one another to form a long chain compound called a
คำตอบ
(C)
polymer
33
Which of the following compounds determines the octane rating of petrol?
คำตอบ
(D)
2,2,4 - trimethyl pentane
34
Which type of reaction is illustrated by the following equation? C12H26 → 5C 2H4 + C 2H6
คำตอบ
(B)
Cracking
35
The IUPAC name of the following organic compound is HOOC - COOH
คำตอบ
(A)
ethan - 1, 2 -dioc acid
36
The enzyme that catalyses the conversion of glucose te ethanol and carbon (IV) oxide is
คำตอบ
(D)
zymase
37
A colourless hydrocarbon with a sweet smell undergoes substitution reaction. The hydrocarbon is likely to be
คำตอบ
(C)
ester
38
The liquid hydrocarbon likely to be found in the fraction of crude oil used for domestic cooking is?
คำตอบ
(A)
C3H8
39
Consider the reaction represented by the following equation: C2H4(g)
+ 302(g) → 2CO2(g) + 2H2O(g)How many moles of ethene would be burnt to produce 0.1 mole of water?
คำตอบ
(A)
0.05 mole
40
Which of the following organic compounds could be represented by the empirical formula CH2O?
