The mass spectrometer can be used to measure mass of
отговор
(A)
an atom
2
Find the number of neutrons in an atom represented by 4521X.
отговор
(B)
24
3
The valence electrons in a chloride ion are [17CI]
отговор
(B)
3s and 3p electrons only
4
What is the atomic number of an element whose cation Y+ has the electronic configuration 1s22s22p6?
отговор
(C)
11
5
Atom \(^{234} _{88} Q\) decay by alpha emission to give an atom R. The atomic number and mass number of atom R are respectively
отговор
(A)
86 and 230
6
Which of the following statements is not true of halogens?
отговор
(C)
their ionic radii decrease down the group
7
Elements in the same group of the periodic table have
отговор
(A)
the same number of valence electrons
8
Consider the following elements and their electronic configurations
W: 1s22s2
X: 1s 22s22p6
Y: 1s22s22p63s2
Z: 1s22s22p63s23p2. Which of the elements belong to the same group in the periodic table?
отговор
(C)
W and Y only
9
Arrange the following elements in order of increasing electron affinity: Br2CI2
I 2
F 2
отговор
(B)
I 2Br2CI2F 2
10
Water molecules are held together by
отговор
(B)
hydrogen bond
11
The force of attraction between covalent molecules is?
отговор
(A)
electrostatic attraction
12
What is the mass of 6.02 x 1024 atoms of magnesium? [Mg = 24, Avogadro constant = 6.02 x 1023 atoms mol-1]
отговор
(A)
240g
13
Which of the following compounds with the corresponding masses contain the highest percentage of nitrogen? [N = 14]
отговор
(A)
NH3 = 17
14
Which of the following compounds with the corresponding masses contain the highest percentage of nitrogen? [N = 14]
отговор
(A)
NH3 = 17
15
If 5.00cm3 of 0.20 mol dm-3Na2CO3 was diluted with distilled water to obtain 250 cm3 solution, what is the concentration of the resulting solution?
отговор
(A)
0.004 mol dm-3
16
Consider the reaction represented by the following equation: Zn(s) + 2HCI(aq) → ZnCI2(aq) + H2(g) what volume of hydrogen gas is produced at s.t.p. when 3.25 g of zinc reacts with excess dilute HCI? [Zn = 65, Molar gas volume at s.t.p. = 22.4 dm-3]
отговор
(A)
1.12 dm3
17
Which of the following gases has the lowerst rate of diffusion under the same conditions of temperature and pressure? [H = 1, O = 16, Ne = 20, CI = 35]
отговор
(A)
Chlorine
18
In a fixed volume of a gas, an increase in temperature results in an increase in pressure due to an increase in the
отговор
(A)
number of the collisions between the gas molecules and the walls of the container
19
When concentrated \(H_2SO_4\) is added to NaCI (s), the gas evolved
отговор
(B)
forms a white preciptate with AgNO3(aq)
20
The collision theory proposes that
отговор
(C)
reactants must collide with a certain minimum amount of energy to from products
21
Diamond does not conduct electricity because it?
отговор
(A)
has no free valence electrons
22
Which of the following set of equations could be used to represent the standard enthalpy of formation of glucose?
отговор
(B)
6CO2(g) + 6H2O (l) → C6H12O6(s) + 6O 2(g)
23
The colour of phenolphthalein indicator in dilute HNO is
отговор
(A)
colourless
24
An aqueous solution of CaCI2 is
отговор
(D)
a neutral solution
25
Which of the following compounds would dissolved in water to give a solution whose pH is less than 7?
отговор
(A)
AI(NO3)3
26
Consider the reaction represented by the question below: KOH(aq) + HCI(aq) → KCI(aq) + H2O(l) What volume of 0.25 mol dm-3 KOH would be required to completely neutralize 40 cm3 of 0.10 mol dm -3 HCI?
отговор
(D)
16cm3
27
When 100 cm3 of a saturated solution of KCIO3 at 40oC is evaporated, 14 g of the salt is recovered what is the solubility of KCIO3 at 40oC? [KCIO3 = 122.5]
отговор
(C)
1. 14 mol dm-3
28
The high solubility of ethanol in water is due to its
отговор
(D)
hydrogen bonding
29
Consider the equilibrium reaction represented by the equation: 2SO2(g) + O2(g) ⇌ 2SO3(g) ∆H = - 197 kJmol-1. At equilibrium, increase in the total pressure of the system brings about
отговор
(C)
increase in temperature of SO3
30
In dry Leclanche cell, manganese (IV) oxide acts as
отговор
(D)
depolarizer
31
Oxidation takes place at the anode during electrolysis because the anode
отговор
(C)
has excess electrons
32
Calculate the quantity of electricity passed when 0.4 A flows for 1 hour 20 minutes through an electrolytic cell
отговор
(C)
1920 C
33
A mixture of kerosene and diesel oil can be separated by
отговор
(B)
distillation
34
Which of the following compounds would not give a precipitate with ammoniacal AgNO3 solution?
отговор
(A)
CH3 C≡CCH3
35
When ethanol is heated with excess concentrated tetraoxosulphate (VI) acid, the organic product formed is
отговор
(D)
ethene
36
The hydrolysis of groundnut oil by potassium hydroxide is known as
отговор
(B)
saponification
37
What is the main type of reaction alkenes undergo?
отговор
(A)
Addition
38
Arrange the following compounds in order of increasing boiling point
l.CH\(_3\)CH\(_2\)CH\(_2\)OH
II.CH\(_3\)CH\(_2\)OH
III.CH\(_3\)CH\(_2\)CH\(_2\)CH\(_2\)OH
IV.CH\(_3\)CH\(_2\)CH\(_2\)CH\(_2\)CH\(_3\)
отговор
(D)
IV < II < I< III
39
A hydrocarbon containing 88.9% carbon has the empirical formula [H = 1 C = 12]
отговор
(B)
CH2
40
A solution of a salt was acidified with HCI when a few drops of BaCI2 solution were added, a white precipitate was formed. Which of the following anions is present in the salt?
