Which of the following is an example of a mixture?
Trả lời
(B)
Blood
2
Calculate the percentage by mass of nitrogen in calcium trioxonitrate (V)
[Ca = 40, N = 14, O = 16]
Trả lời
(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?
Trả lời
(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?
Trả lời
(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?
Trả lời
(B)
increase in nuclear charge
6
How many unpaired electron(s) are there in the nitrogen sub-levels?
Trả lời
(A)
3
7
The stability of the noble gases is due to the fact that they?
Trả lời
(B)
have duplet or octet electron configurations
8
The maximum number of electrons in the L shell of an atom is?
Trả lời
(B)
8
9
Elements in the same period in the periodic table have the same?
Trả lời
(A)
number of shells
10
12D + 13T → 24He + 01n + energy
The reaction above illustrates?
Trả lời
(C)
nuclear fussion
11
A noble gas with a high power of fog penetration used in aerodrome beacons is?
Trả lời
(A)
krypton
12
Permanent hardness of water can be removed by?
Trả lời
(C)
adding caustic soda
13
Substance employed as drying agents are usually?
Trả lời
(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]
Trả lời
(B)
2.50
15
Coffee stains can best be removed by?
Trả lời
(C)
a solution of borax in water
16
Carbon (II) oxide is considered dangerous if inhaled mainly because it?
Trả lời
(B)
competes with oxygen in the blood
17
The acid that is used to remove rust is?
Trả lời
(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?
Trả lời
(B)
2.5 cm3
19
The colour of methyl orange in alkaline medium is?
Trả lời
(A)
yellow
20
Which of the following salts is slightly soluble in water?
Trả lời
(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?
Trả lời
(C)
PH3(g)
22
The IUPAC nomenclature of the compound LiAlH4 is?
Trả lời
(A)
lithiumtetrahydridoaluminate (III)
23
Iron can be protected from corrosion by coating the surface with?
Trả lời
(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]
Trả lời
(B)
1.8 g
25
In which of the following is the entropy change positive?
Trả lời
(A)
Thermal dissociation of ammonium chloride
26
If a reaction is exothermic and there is a great disorder, it means that?
Trả lời
(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?
Trả lời
(C)
increase the rate of the reaction
28
The graph above demonstrate the effect of?
Trả lời
(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?
Trả lời
(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?
Trả lời
(D)
NO\(^{2-}_{3}\)
31
Which of the following is used in rocket fuels?
Trả lời
(A)
HNO3
32
A constituent common to bronze and solder is?
Trả lời
(D)
tin
33
When iron is exposed to moist air, it gradually rusts. This is due to the formation of?
Trả lời
(A)
hydrate iron (III) oxide
34
A compound gives an orange-red color to non-luminous flame. This compound is likely to contain?
Trả lời
(B)
Ca2+
35
Stainless steel is used for making?
Trả lời
(B)
tools
36
The residual solids from the fractional distillation of petroleum are used as?
Trả lời
(A)
coatings of pipes
37
The IUPAC nomenclature of the compound above is?
Trả lời
(A)
4 - ethyloctane
38
Which of the following is used as fuel in miners' lamp?
Trả lời
(B)
Ethyne
39
Which of the following organic compounds is very soluble in water?
Trả lời
(A)
CH3COOH
40
Benzene reacts with hydrogen in the presence of nickel catalyst at 180ºC to give?
Trả lời
(D)
cyclohexane
41
Which of the following is used to hasten the ripening of fruit?
Trả lời
(A)
Ethene
42
The final products of the reaction between methane and chlorine in the presence of ultraviolet light are hydrogen chloride and?
Trả lời
(C)
tetrachloromethane
43
The correct order of increasing boiling points of the following compounds C3H7OH, C7H16 and C4H10 is?
Trả lời
(D)
C4H10 → C3H7OH → C7H16
44
One of the major uses of alkane is?
Trả lời
(A)
as domestic and industrial fuel
45
The haloalkanes used in dry-cleaning industries are?
