Which of the following is an example of a mixture?
คำตอบ
(B)
Blood
2
Calculate the percentage by mass of nitrogen in calcium trioxonitrate (V)
[Ca = 40, N = 14, O = 16]
คำตอบ
(C)
17.1%
3
The droplets of water observed around a bottle of milk taken out of the refrigerator is due to the fact that the?
คำตอบ
(D)
water vapour in the air around the bottle loses some of its energy to the bottle
4
The volume of a given gas is V cm\(^3\) at a pressure P mm Hg. what is the new volume of the gas if the pressure is reduced to half at constant temperature?
คำตอบ
(B)
2 V cm3
5
Moving from left to right across a period, the general rise in the first ionization energy can be attributed to the?
คำตอบ
(B)
increase in nuclear charge
6
How many unpaired electron(s) are there in the nitrogen sub-levels?
คำตอบ
(A)
3
7
The stability of the noble gases is due to the fact that they?
คำตอบ
(B)
have duplet or octet electron configurations
8
The maximum number of electrons in the L shell of an atom is?
คำตอบ
(B)
8
9
Elements in the same period in the periodic table have the same?
คำตอบ
(A)
number of shells
10
12D + 13T → 24He + 01n + energy
The reaction above illustrates?
คำตอบ
(C)
nuclear fussion
11
A noble gas with a high power of fog penetration used in aerodrome beacons is?
คำตอบ
(A)
krypton
12
Permanent hardness of water can be removed by?
คำตอบ
(C)
adding caustic soda
13
Substance employed as drying agents are usually?
คำตอบ
(B)
hygroscopic
14
Calculate the solubility in mol dm-3 of 40g of CuSO4 dissolved in 100g of water at 120°C?
[Cu = 64, S = 32, O = 16]
คำตอบ
(B)
2.50
15
Coffee stains can best be removed by?
คำตอบ
(C)
a solution of borax in water
16
Carbon (II) oxide is considered dangerous if inhaled mainly because it?
คำตอบ
(B)
competes with oxygen in the blood
17
The acid that is used to remove rust is?
คำตอบ
(B)
hydrochloric
18
Calculate the volume of 0.5 mol dm\(^{-3}\) H\(_2\)SO\(_4\) that is neutralized by 25 cm\(^3\) of 0.1 mol dm\(^3\) NaOH?
คำตอบ
(B)
2.5 cm3
19
The colour of methyl orange in alkaline medium is?
คำตอบ
(A)
yellow
20
Which of the following salts is slightly soluble in water?
คำตอบ
(B)
CaSO4
21
6\(AgNO_{4(aq)} + PH_{3(g)} + 3H_2O_{(l)}\) → 6\(Ag_{(s)} + H_3PO_{3(g)} + 6HNO_{3(aq)}\)
In the above reaction, the reducing agent is?
คำตอบ
(C)
PH3(g)
22
The IUPAC nomenclature of the compound LiAlH4 is?
คำตอบ
(A)
lithiumtetrahydridoaluminate (III)
23
Iron can be protected from corrosion by coating the surface with?
คำตอบ
(D)
zinc
24
What quantity of aluminum is deposited when a current of 10A is passed through a solution of an aluminum salt for 1930s?
[Al = 27, F = 96500 C mol -1]
คำตอบ
(B)
1.8 g
25
In which of the following is the entropy change positive?
คำตอบ
(A)
Thermal dissociation of ammonium chloride
26
If a reaction is exothermic and there is a great disorder, it means that?
คำตอบ
(D)
there will be a large decrease in free energy
27
In the preparation of oxygen by heating KClO3 in the presence of MnO2, only moderate heat is needed because the catalyst acts by?
คำตอบ
(C)
increase the rate of the reaction
28
The graph above demonstrate the effect of?
คำตอบ
(A)
surface area on the rate of reaction
29
2H2(g) + O2(g) ⇌ 2H2O(g) ΔH = -ve
what happens to the equilibrium constant of the reaction above if the temperature is increased?
คำตอบ
(C)
it decrease
30
To a solution of an unknown compound, a little dilute tetraoxosulphate (VI) acid was added with some freshly prepared iron (II) tetraoxosulphate (VI) solution. The brown ring observed after the addition of a stream of concentrated tetraoxosulphate (VI) acid confirmed the presence of?
คำตอบ
(D)
NO\(^{2-}_{3}\)
31
Which of the following is used in rocket fuels?
คำตอบ
(A)
HNO3
32
A constituent common to bronze and solder is?
คำตอบ
(D)
tin
33
When iron is exposed to moist air, it gradually rusts. This is due to the formation of?
คำตอบ
(A)
hydrate iron (III) oxide
34
A compound gives an orange-red color to non-luminous flame. This compound is likely to contain?
คำตอบ
(B)
Ca2+
35
Stainless steel is used for making?
คำตอบ
(B)
tools
36
The residual solids from the fractional distillation of petroleum are used as?
คำตอบ
(A)
coatings of pipes
37
The IUPAC nomenclature of the compound above is?
คำตอบ
(A)
4 - ethyloctane
38
Which of the following is used as fuel in miners' lamp?
คำตอบ
(B)
Ethyne
39
Which of the following organic compounds is very soluble in water?
คำตอบ
(A)
CH3COOH
40
Benzene reacts with hydrogen in the presence of nickel catalyst at 180ºC to give?
คำตอบ
(D)
cyclohexane
41
Which of the following is used to hasten the ripening of fruit?
คำตอบ
(A)
Ethene
42
The final products of the reaction between methane and chlorine in the presence of ultraviolet light are hydrogen chloride and?
คำตอบ
(C)
tetrachloromethane
43
The correct order of increasing boiling points of the following compounds C3H7OH, C7H16 and C4H10 is?
คำตอบ
(D)
C4H10 → C3H7OH → C7H16
44
One of the major uses of alkane is?
คำตอบ
(A)
as domestic and industrial fuel
45
The haloalkanes used in dry-cleaning industries are?
