An element X has 127 neutrons and 82 electrons.
Its atomic number is?
Răspuns
(D)
82
2
When a bottle of Coca-Cola is opened, bubbles of evolve. The gas is?
Răspuns
(C)
carbon dioxide
3
When glowing splint is inserted into the mouth of a jar containing a gas, the splint is extinguished. The gas gives a white precipitate when passing into barium hydroxide. The gas is?
Răspuns
(E)
carbondioxide
4
An example of a strong electrolyte is?
Răspuns
(D)
sodium formate
5
The oxidation number of manganese in KMnO4 is?
Răspuns
(D)
+7
6
Methane is member of the homologous series called?
Răspuns
(D)
alkanes
7
For iron to rust, there should be present?
Răspuns
(D)
oxygen and moisture
8
The mass number of an atom is?
Răspuns
(E)
the sum of numbers of proton and neutrons in the nucleus of the atom
9
Sodium and potassium belong to the same group of the Periodic Table. This is because?
Răspuns
(D)
both have identical electronic configuration
10
Oxidation is the process of?
Răspuns
(B)
loss of electrons
11
the number of atoms in one mole of a substance is equal to?
Răspuns
(B)
the avogadro number
12
Which of the following statements is NOT true of electrovalent compounds?
Răspuns
(D)
The elements forming the compounds normally have their valency electrons in a shared state
13
If concentrated sulphric acid is added to sugar and warmed gently, the sugar changes from white to brown and finally to a black mas of carbon. In this reaction, concentrated sulphuric acid is acting as ?
Răspuns
(C)
a dehydrated agent
14
In the reaction
C + 2HNO3 → CO2 + NO2 + NO + H2O nitric acid is acting as?
Răspuns
(C)
an oxidizing agent
15
The brown coloration in nitric acid prepared in the laboratory can be removed by?
Răspuns
(B)
bubbling air through the acid
16
Which of the following processes takes place during electrolysis?
Răspuns
(D)
Negative ions are discharge at the anode by losing sufficient electrons to become neutral
17
In the preparation of ammonia, which of the following is used as the drying agent?
Răspuns
(A)
CaO
18
Which of the following can have an isomer?
Răspuns
(B)
C4H10
19
Allotropes are elements having?
Răspuns
(A)
different physical but the same chemical properties
20
A polymerization reaction is one in which?
Răspuns
(A)
small molecules form giant molecules
21
Which of the following is the electronic configuration of sodium?
(Atomic number of Na = 11)
Răspuns
(C)
1s2 2s22p6 3s1
22
In the reaction of oxygen with hydrogen to produce water, which of the following statements is true?
Răspuns
(E)
One molecule of oxygen reacts with two molecules of hydrogen to give two molecules of water
23
Na2CO3 + 2HCI → 2NaCI + H2O + CO2. Using the above equation, what volume of carbondioxide, measured at s.t.p is liberated when 53g of sodium carbonate is dissolved in hydrochloric acid?
(1 mole of gas occupies 22.4 dm3 at s.t.p)
(Na = 23, C = 12, O = 16)
Răspuns
(B)
11.2 dm3
24
When sodium nitrate dissolves in water, ∆H is positive. This means that?
Răspuns
(D)
the reaction is endthermic
25
If an organic compound decolorizes bromine water then the compound is?
Răspuns
(C)
unsaturated
26
When air is compressed?
Răspuns
(D)
its temperature increases
27
Fats and oils are?
Răspuns
(C)
condensation products of long-chain fatty acids and glycerol
28
Which of the following statements about phosphorus is NOT correct?
Răspuns
(C)
Phosphorus exists in two allotropic forms
29
28.8 cm3 of nitrogen at 15°C is cooled to O°C at constant pressure, the new volume of nitrogen is?
Răspuns
(C)
27.3 cm3
30
If 48,000 coulombs of electricity are required to discharge 0.5 mole of sodium from a molten sodium chloride mass, then the number of coulombs required to discharge 2 moles of lead from molten lead (ll) chloride is?
Răspuns
(D)
384,000
31
The following compounds are given with their corresponding boiling points.
Compound Boiling Point
i.................................14°C
ii................................24°C
iii................................0°C
iv................................120°C
V.................................-2°C
From the above information, indicate which of the following is correct?
Răspuns
(D)
Three of the compounds are gaseous at 20 °C
32
The products of the reaction between dilute sulphuric acid and sodium thiosulphate crystals are?
Răspuns
(C)
Na2SO4 + SO2 + S + H2O
33
Which of the following is NOT a true statement of the kinetic Theory of Gases?
Răspuns
(D)
Every molecule has the same kinetic energy at a particular temperature
34
The electronic configuration of elements X and Y are X = 2, 8, 6; Y = 2, 8, 7. The bond in the compound formed by X and Y is expected to be?
Răspuns
(B)
covalent
35
5cm3 of a saturated solution of sodium chloride at 30°C gave, on careful evaporation, 1.95g of solid salt. The solubility of sodium chloride at 30°C?
(Na = 23, Cl = 35.5)
Răspuns
(D)
6.67 mole dm3
36
In the extraction of iron, which of the following reactions does NOT take place in the blast furnace?
Răspuns
(B)
2Fe2O3 + 3C → 4Fe + 3CO2
37
Pure sulfuric acid is a liquid of 1.84 density. What volume of it would be required to prepare 250 cm3 of 2.0 M solution?
(H = 1, S = 32, O = 16)
Răspuns
(B)
2.66
38
What mass of sodium carbonate solution is in 500 cm3 of 0.1 molar sodium carbonate solution?
(Na = 23, C = 12, O = 16)
Răspuns
(B)
5.3 g
39
Which of the following compounds and elements would sublime on exposure to the atmosphere?
Răspuns
(D)
Iodine
40
When hydrogen sulphide and sulphur dioxide are each passed in turn into a solution of potassium dichromate?
Răspuns
(E)
only hydrogen sulphide deposits sulphur
41
Which one of the following metals is not normally extracted by chemical reduction because of its position in the electrochemical series?
Răspuns
(D)
Potassium
42
If one mole of aluminium contains 6 x 1023 atoms of aluminium, how many atoms are contained in 0.9g of aluminium?
(Al = 27)
Răspuns
(C)
2.0 x 1022
43
4g each of aluminium foil and aluminium powder were introduced respectively into flasks P and Q.
Flask P was treated with warm bench sodium hydroxide and all the aluminium dissolved in one hour. Flask Q was treated with cold sodium hydroxide and all the aluminium dissolved in 10 minutes. What was responsible for Q reacting faster than P?
Răspuns
(E)
Q has a greater surface area for the reaction than P
44
What happens when the nitrates of potassium, calcium, zinc and copper are separately heated?
Răspuns
(E)
The nitrates of calcium, zinc and copper decompose to their oxides
45
The scale formation in a kinetic used for boiling water is caused by the presence in water of?
