25cm\(^3\) of a gas X contains Z molecules at 15\(^0\)C and 75 mmHg. How many molecules will 25cm\(^3\) of another gas Y contain at the same temperature and pressure?
Відповідь
(C)
Z
2
What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen?
[H = 1, O = 16]
Відповідь
(C)
72.0g
3
A particle that contains 9 protons, 10 neutrons and 10 electrons is a
Відповідь
(A)
negative ion
4
Cancerous growths are cured by exposure to
Відповідь
(A)
γ - rays
5
An oxide XO\(_2\) has a vapour density of 32. What is the atomic mass of X?
Відповідь
(A)
32
6
Millikan's contributions to the development of atomic theory is the determination of
Відповідь
(A)
charge on electron
7
Four elements W, X, Y and Z have atomic number 2,6,16 and 20 respectively. Which of these elements is a metal?
Відповідь
(C)
Z
8
An element X with relative atomic mass 16.2 contains two isotopes \(^{16}_{8}\)X with relative abundance of 90% and \(^{m}_{8}\)X with relative abundance of 10%. The value of m is
Відповідь
(B)
18
9
Which of the following statements is correct about the average kinetic energy of the molecules of a gas?
Відповідь
(C)
It increase with increase in temperature
10
The pollution from petroleum spillage in rivers and lakes can best be dispersed by
Відповідь
(B)
Passing of ships through the area
11
Deliquescent substances are used for
Відповідь
(D)
Drying
12
Pure solvents are obtained by
Відповідь
(A)
Distillation
13
What is the decrease in volume of air when pyrogallol is shaken with 30.00cm\(^3\) of air ?
Відповідь
(B)
6.30cm3
14
Environmental pollution is worsened by the release from automobile exhausts of?
Відповідь
(C)
Smoke
15
The chemical used for coagulation in water purification is
Відповідь
(A)
Aluminium tetraoxosulphate (VI)
16
Phosphorus is stored under water to prevent it from
Відповідь
(D)
Catching fire
17
In which of the following reactions does reduction takes place
Відповідь
(D)
2H+ + 2e- → H2
18
P(g) + Q(g) ↔ 3R(s) + S(g) ΔH is negative
Which of the following will increase the yield of R?
Відповідь
(C)
Removing some S
19
A metal M displaces zinc from zinc chloride solution. This shows that
Відповідь
(C)
M is more electropositive than zinc
20
Which of the following best explains the increase in the rate of a chemical reaction as the temperature rises?
Відповідь
(D)
The collision frequency of the molecules increase
21
What current in amperes will deposit 2.7g of aluminium in 2 hours?
[Al = 27, F = 96 500 C mol-1]
Відповідь
(C)
4
22
Ethanoic acid is
Відповідь
(C)
monobasic
23
C(s) + 2S(g) → CS\(_2\)(g)
ΔH = +89 kJ mol-1
The chemical equation above implies that
Відповідь
(D)
89 kJ of energy is absorbed
24
2SO\(_2\)(g) + O\(_2\)(g) ↔ 2SO\(_3\)(g)
ΔH = -189 kJ mol-1
The equilibrium constant for the reaction above is increased by?
Відповідь
(A)
decreasing the temperature of the system
25
3Cu(s) + 8HNO\(_3\)(aq) → 3Cu(NO\(_3\))\(_2\)(aq) + 4H\(_2\)O(l) + 2NO(g)
In the equation above, copper is
Відповідь
(D)
a reducing agent
26
When ΔH is negative, a reaction is said to be
Відповідь
(C)
exothermic
27
As the concentration of an electrolyte reduces, the conductivity
Відповідь
(B)
decreases
28
In which of the following reactions has the oxidation number of nitrogen increased?
Відповідь
(B)
2NO(g) + O2(g) → 2NO2(g)
29
NH\(_3\)\(_{(g)}\) + HCl\(_{(g)}\) → NH\(_4\)Cl\(_{(s)}\)
The entropy change in the system above is
Відповідь
(A)
negative
30
Fermentation is the
Відповідь
(B)
conversion of sugar to alcohol in the presence of yeast
31
The general formula for the alkanals is
Відповідь
(D)
RCHO
32
The main impurity in iron ore during the extraction of iron is
Відповідь
(A)
Silicon (IV) oxide
33
During the vulcanization of rubber, sulphur is added to
Відповідь
(C)
Bind rubber molecules together
34
Catalytic hydrogenation of benzene produces
Відповідь
(C)
Cyclohexane
35
A trihydric alkanol is
Відповідь
(A)
Glycerol
36
When chlorine Is passed into water and the resulting solution exposed to sunlight, the product formed are
Відповідь
(D)
Hydrochloric acid and oxygen
37
Proteins in acid solution undergo
Відповідь
(D)
Hydrolysis
38
A characteristic reaction of the compounds with the general formula C\(_n\)H\(_{2n}\) is
Відповідь
(B)
Polymerization
39
The pair of organic compounds that are isomers is
Відповідь
(D)
But-1-ene and but-2-ene
40
A burning candle produces water and
Відповідь
(B)
Carbon (IV) oxide
41
The gas that can best be collected by downward displacement of air is
Відповідь
(C)
Ammonia
42
Which of the following metals burn with brick red flame?
Відповідь
(B)
Ca
43
Which of the following represent hybridization in ethyne?
Відповідь
(D)
Sp
44
\(C_{12}H_{22}O_{11(s)} + H_2SO_{4(aq)} → 12C(s) + 11H_2O(l) + H_2SO_{4(aq)}\)
In the reaction above, tetraoxosulphate (VI) acid function as
Відповідь
(A)
A dehydrating agent
45
When sodium reacts with water, the resulting solution is
