If the relative molecular mass of an element is not a whole number, it can be deduced that the element is
Răspuns
(D)
an isotopic mixture
2
The atomic number of chlorine is 17. What is the number of electrons in a chloride ion?
Răspuns
(C)
18
3
Consider the following equation; Cr2O7(aq)2- + 14H+(aq) + 6e- → 2Cr3+(aq) + 7H2O(I). The oxidation number of chromium changes from
Răspuns
(C)
+ 6 to + 3
4
Which of the following ions require the largest quantity of electricity for discharge at an electrode?
Răspuns
(A)
2.0 mole of Q 3+
5
If two metallic ions of the same concentration migrate to a graphite cathode, the one that would be preferentially discharged is the one that has the
Răspuns
(D)
stronger tendency to accept electrons
6
When concentrated sodium chloride solution is electrolysed using inert electrodes the products are?
Răspuns
(D)
soduim hydroxide, hydrogen and chlorine
7
Which of the following processes takes place during the production of margarine from vegetable oils?
Răspuns
(C)
Hydrogenation
8
Which of the following compounds can be represented by the molecular formula C2H6O?
Răspuns
(B)
Ethanol
9
When alkynes are hydrogenated completely, they produce compounds with the general molecular formula
Răspuns
(B)
C nH 2n+2
10
The following compounds are hydrocarbons except
Răspuns
(A)
methylpropanoate
11
Which of the following statements about soapless detergents is correct? They
Răspuns
(A)
lather readily with hard water
12
If the relative molecular mass of an element is not a whole number, it can be deduced that the element is
Răspuns
(D)
an isotopic mixture
13
The atom of an element X is represented as \(^y_z X\). The basic chemical properties of X depend on the value of
Răspuns
(B)
Z
14
The atomic number of chlorine is 17. What is the number of electrons in a chloride ion?
Răspuns
(C)
18
15
A hydrogen atom which has lost an electron contains
Răspuns
(A)
one proton only
16
Which of the following elements has a ground state electronic configuration with an incomplete penultimate shell?
Răspuns
(A)
Iron
17
The conclusion from Rutherford's alpha-scattering experiment is that
Răspuns
(A)
atoms are mostly empty space with a small nucleus
18
An element Y has the electronic configuration 1s22s22p6623p4. To what period does it belong in the periodic table?
Răspuns
(A)
3
19
If a metal R forms a compound with the formula R(NO3)2 , the formula of its tetraoxosulphate (IV) is
Răspuns
(B)
RSO4
20
Which of the following decreases when a given mass of gas is compressed to half its initial volume?
Răspuns
(A)
Average intermolecular distance
21
What volume of hydrogen will be produced if 100cm3 of ammonia is completely decomposed at constant temperature and pressure? The equation for reaction is 2NH3(g) → N2(g) + 3H2(g)
Răspuns
(B)
150cm3
22
Calculate the mass of chlorine gas which occupies a volume of 1.12 dm\(^3\) a volume of 1.12 dm\(^3\) at s.t.p [Cl = 35.5, 1 mole og gas occupies 22.4 dm\(^3\) at s. t. p ]
Răspuns
(B)
3.55g
23
Determine the mass of sulphur (IV) oxide obtained when 91.0g of oxygen reacts completely with sulphur according to the following equation: S(s) + O\(_2\)(g) → SO\(_2\)(g) [S = 32; O = 16]
Răspuns
(D)
182g
24
The gas given off when NH4 Cl is heated with an alkali is
Răspuns
(D)
NH3
25
A major factor considered in selecting a suitable method for preparing a simple salt is its
Răspuns
(D)
solubility in water
26
Which of following acids forms normal salts only?
Răspuns
(C)
Acetic acid
27
A substance is said to be hygroscopic if it absorbs
Răspuns
(D)
moisture from the atmosphere without dissolving
28
Which of the following substances increases in mass when heated in air?
Răspuns
(C)
Magnesium ribbon
29
Calculate the mass of sodium hydroxide in 5.00 dm3 of a 0.125 mol dm-3 solution. [NaOH = 40 g mol-1]
Răspuns
(D)
25.0 g
30
Which of the following salt solutions will have a pH greater than 7?
Răspuns
(B)
Na2CO3(aq)
31
What will happen if more heat is applied to the following system at equilibrium?
What is the expression for the equilibrium constant (Kc) for the following reaction? N2(g) + O2(g) ⇌ 2NO(g)
Răspuns
(D)
\(\frac{[NO]^2}{[N_2][O^2]}\)
33
Equal amounts of marble chips are reacted separately with 100cm3 of hydrochloric acid of different concentrations. If all the marble chips reacted; which of the following remained the same in each case?
Răspuns
(B)
Total mass of gas evolved during the reaction
34
CuSO45H2O can be obtained from an aqueous solution of copper (ll) tetraoxosulphate (VI) by
Răspuns
(D)
crystallization
35
Which of the following compounds will leave a metal residue when heated?
Răspuns
(B)
AgNO3
36
A visible change is observed when a strip of iron is placed in an aqueous solution of
Răspuns
(C)
CuSO4
37
Consider the following equation: Cr\(_2\)O\(_7\)\(^{2-}\)(aq) + 14H\(^+\)(aq) + 6e\(^-\) → 2Cr\(^{3+}\)(ag) + 7H\(_2\)O(1). The oxidation number of chromium changes from
Răspuns
(C)
+6 to +3
38
Which of the following ions require the largest quantity of electricity for discharge at an electrode?
Răspuns
(A)
2.0 mole of Q 3+
39
If two metallic ions of the same concentration migrate to a graphite cathode, the one that would be preferentially discharged is the one that has the
Răspuns
(D)
stronger tendency to accept electrons
40
When concentrated sodium chloride solution is electrolysed using inert electrodes, the products are
Răspuns
(B)
hydrogen and chlorine
41
Which of the following processes takes place during the production of margarine from vegetable oils?
Răspuns
(C)
Hydrogenation
42
Which of the following compounds can be represented by the molecular formula C2H6O?
Răspuns
(B)
Ethanol
43
When alkynes are hydrogenated completely they produce compounds with the general molecular formula
Răspuns
(C)
CnH2n+2
44
The following compounds are hydrocarbons except
Răspuns
(A)
methylpropanoate
45
The reaction between ethene and chlorine to form 1, 2-dichloroethane is
Răspuns
(C)
addition
46
Which of the following statements about soapless detergents is correct? They
Răspuns
(A)
lather readily with hard water
47
Which of the following types of alkanols undergo oxidation to produce alkanoic acids? I. Primary alkanols II. Secondary alkanols III. Tertiary alkanols
Răspuns
(D)
l only
48
A suitable reagent for distinguishing between ethanoic acid ethanol is
