What is the solubility of a salt if 0.4g of it is obtained on evaporating 200\(cm^{3}\) of its saturated solution to dryness?
Απάντηση
(B)
2.00\(gdm^{-3}\)
6
An acidic salt has
Απάντηση
(C)
hydrogen ions in its aqueous solution
7
A reaction is endothermic if the
Απάντηση
(A)
reaction vessel feels cool during the reaction
8
In which of the following compounds does hydrogen form ionic compounds?
Απάντηση
(D)
NaH
9
An organic compound has the empirical formula \(CH_{2}\). If its molar mass is 42\(gmol^{-1}\), what is its molecular formula? (C = 12.0, H = 1.0)
Απάντηση
(C)
\(C_{3}H_{6}\)
10
Consider the following reaction equation: \(Br_{2} + 2KI \to 2KBr + I_{2}\). Bromine is acting as
Απάντηση
(A)
an oxidizing agent
11
Ethene is produced from ethanol by
Απάντηση
(D)
dehydration
12
Consider the following equilibrium reaction: \(2AB_{{2}{(g)}} + B_{{2}{(g)}} \to 2AB_{{3}{(g)}}\). \(\Delta H= -X kJmol^{-1}\). The backward reaction will be favored by
Απάντηση
(A)
a decrease in pressure
13
What is the mass of solute in 500\(cm^{3}\) of 0.005\(moldm^{-3}\) \(H_{2}SO_{4}\)? ( H = 1, S = 32.0, O=16.0)
Απάντηση
(C)
0.245g
14
Pure water can be made to boil at a temperature lower than 100°C by
Απάντηση
(B)
decreasing the external pressure
15
At what temperature does the solubility of \(KNO_{3}\) equal that of \(NaNO_{3}\)?
Απάντηση
(B)
20°C
16
When a salt is added to its saturated solution, the salt
Απάντηση
(C)
precipitates and the solution remains unchanged
17
When substance X was added to a solution of bromine water, the solution became colourless. X is likely to be
Απάντηση
(C)
propyne
18
The preferential discharge of ions during electrolysis is influenced by the
Απάντηση
(C)
nature of the electrode
19
The valence electrons of \(_{12}Mg\) are in the
Απάντηση
(A)
3s orbital
20
Stainless steel is an alloy comprising of
Απάντηση
(C)
Fe, C and Ni
21
The number of Hydrogen ions in 1.0\(dm^{3}\) of 0.02\(moldm^{-3}\) tetraoxosulphate(VI) acid is \([N_{A} = 6.02 \times 10^{23}]\)
Απάντηση
(A)
\(1.2 \times 10^{22}\)
22
The most suitable substance for putting out petrol fire is
Απάντηση
(B)
carbon(IV) oxide
23
The following factors would contribute to environmental pollution except
Απάντηση
(C)
photosynthesis
24
The position of equilibrium in a reversible reaction is affected by
Απάντηση
(D)
change in concentration of the reactants
25
The diagram above illustrates a conical flask containing water and ice. Which of the following is correct about the diagram?
Απάντηση
(B)
Energy is absorbed when the ice changes to water
26
Which of the following statements best explains the difference between a gas and a vapour?
Απάντηση
(B)
Unlike gases, vapour can easily be condensed into liquids
27
Consider the following reaction equation: \(2HCl + Ca(OH)_{2} \to CaCl_{2} + H_{2}O\). What is the volume of 0.1\(moldm^{-3}\) HCl that would completely neutralize 25\(cm^{3}\) of 0.3\(moldm^{-3}\) Ca(OH)\(_{2}\)?
Απάντηση
(A)
150\(cm^{3}\)
28
\(Cu\) and \(HNO_{3}\) are not suitable for preparing hydrogen gas because of their
Απάντηση
(A)
reactivity and oxidation respectively
29
Which of the following CANNOT be an empirical formula?
Απάντηση
(D)
\(N_{2}O_{4}\)
30
One of the criteria for confirming the purity of benzene is to determine its
Απάντηση
(B)
boiling point
31
When chlorine is passed through a sample of water, the pH of the water sample would be
Απάντηση
(A)
< 7
32
How many atoms are contained in 0.2moles of nitrogen? \([N_{A} = 6.02 \times 10^{23}]\)
Απάντηση
(A)
\(1.20 \times 10^{23}\)
33
The strength of metallic bonds depends on the
Απάντηση
(C)
number of valence electrons
34
When zinc is added to AgNO\(_{3}\) solution, crystals of silver forms on the zinc surface. This indicates that zinc is
Απάντηση
(A)
oxidised
35
The empirical formula of a compound containing 0.067mol Cu and 0.066mol O is [Cu = 63.5, O = 16]
Απάντηση
(B)
\(CuO\)
36
The change in the oxidation state of iron in the reaction represented by the equation: \(2FeCl_{3} + H_{2}S \to 2FeCl_{2} + 2HCl + S\) is
Απάντηση
(C)
+3 to +2
37
Which of the following methods can be used to seperate blood cells from plasma?
Απάντηση
(A)
Centrifugation
38
Which of the following statements is true about ionic radius? Ionic radius
Απάντηση
(B)
decreases as nuclear charge increases
39
Analysis of a hydrocarbon shows that it contains 0.93g of Carbon per gram of the compound. The mole ratio of carbon to hydrogen in the compound is [H = 1.0, C=12.0]
Απάντηση
(A)
1:1
40
The law of definite proportions states that
Απάντηση
(A)
pure samples of the same compound contain the same elements combined in the same proportion by mass
41
What is the relative molecular mass of a compound which has empirical formula \(CH_{2}O\)? [C= 12, H= 1, O= 16]
Απάντηση
(D)
180
42
Atoms are electrically neutral because they
Απάντηση
(B)
contain equal number of protons and electrons
43
Common Salt (NaCl) is used to preserve foods. Which of the following properties can be used to determine its purity before use?
Απάντηση
(B)
Melting point
44
Which of the following electron configurations represents the transition element Chromium \(_{24}Cr\)?
Απάντηση
(D)
\(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}3d^{5}\)
45
The atomic number of an isotope of hydrogen is equal to its mass number because it
