At constant temperature, the volume of a gas increases as the pressure increases
2
The ion that may be assumed to have negligible concentration in a sample of water that lathers readily with soap is?
отговор
(A)
Mg+
3
A substance S is isomorphous with another substance R. When a tiny crystals of S is added into a supersaturated solution of R?
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(B)
crystals of R are precipitated
4
Which of the following dilute solutions has the lowest pH value?
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(C)
Hydrochloric acid
5
Which of the following in aqueous solution is neutral to litmus?
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(D)
NaCl
6
What volume of a 0.1 M H\(_3\)PO\(_4\) will be required to neutralize 45.0 cm\(^3\) of a 0.2 M NaOH?
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(D)
30.0 cm3
7
Which of the following substances is a basic salt?
отговор
(B)
Mg(OH)CI
8
Which of the following acts both s a reducing and an oxidizing agent?
отговор
(B)
SO2
9
Which of the following reactions takes place in the cathode compartment during the electrolysis of copper (II) chloride solution?
отговор
(A)
Cu2+ + 2e- → Cu(s)
10
A mixture of starch solution and potassium iodide was placed in a test tube. On adding dilute tetraoxosulphate (lV) acid and then K2Cr2O7 solutions, a blue-black colour was produced. In this reaction, the?
отговор
(C)
starch has been oxidized
11
Which of the following will produce the greatest increase in the rate of the chemical reaction represented by the equation Na2S2O3(aq) + 2HCl(aq) → 2NaCI(aq) + H2O(I) + SO2(g) + S(g)?
отговор
(C)
An increase in temperature and an increase in the concentration of the reactants
12
Which of the followingstatements is TRUE?
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(D)
The heat of solution of NaOH(s) is negative
13
Which property of a reversible reaction is affected by a catalyst?
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(B)
Energy of activation
14
Which of the following is used in fire extinguishers?
отговор
(B)
Carbon (lV) oxide
15
When H2S gas is passed into a solution of iron (III) chloride, the colour changes from yellow to green. This is because?
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(D)
Fe3+ ions are reduced to Fe2+ ions
16
Suitable reagents for the laboratory preparation nitrogen are?
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(A)
sodium dioxonitrate (III) and ammonium chloride
17
The thermal decomposition of copper (ll)trioxonitrate (V) yields copper (ll) oxide, oxygen and?
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(C)
nitrogen (lV) oxide
18
Chlorine is produced commmercially by?
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(B)
electrolysis of brine
19
Aluminium is extracted commercially from its ore by?
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(B)
the electrolysis of fused aluminium oxide in cryolite
20
Given the reactions (i) Fe(s) + X(NO3)2(aq) → Fe(NO3) + X(s) (ii) H2(g) + XO → X + H2O(s); X is likely to be?
отговор
(A)
copper
21
Crude copper can be purified by the electrolysis of CuSO4(aq) if?
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(B)
the crude copper is made the anode of the cell
22
Methylethanoate reacts with ammonia to yield?
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(D)
ethanamide and methanol
23
Alkanoates are formed by the reaction of alkanoic acid with?
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(B)
alkanols
24
The four classes of hydrocarbons are?
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(B)
alkanes, alkenes, alkynes and aromatics
25
Which of the following compounds has the highest boiling point?
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(A)
CH3CH2CH2CH2HO
26
Detergents have the general formula?
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(B)
RSO3-Na+
27
What process would coal undergo to give coal gas, coal tar, ammoniacal liquor and coke?
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(B)
Destructive distillation
28
The formula of a compound formed in a reaction between a trivalent metal M and a tetravalent non-metal X is~?
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(C)
M4X3
29
2.25g of a sample of an oxide of copper on reduction gave 2.0g of copper. 2.50g of another oxide of copper on reduction also gave 2.0g of copper. These results are in accordance with the law of?
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(C)
multiple proportions
30
One mole of propane is mixed with five moles of oxygen. The mixture is ignited and the propane burns completely. What is the volume of the products at s.t.p?
(G.M.V = 22.4 dm3 mol-1)
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(B)
67.2 dm3
31
An increase in temperature causes an increase in the pressure of a gas because there is an increase in the?
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(B)
number of collisions between the molecules
32
The forces holding naphthalene crystals together can be overcome when naphthalene is heated to a temperature of 354K resulting in the crystal to melting. These forces are known as?
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(D)
Van der waals
33
A metallic ion X2+ with an inert gas structure contains 18 electrons. How many protons are there in this ion?
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(A)
20
34
Which of the following physical properties decreases across the Periodic Table?
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(D)
Atomic radius
35
What are the possible oxidation numbers of an element if its atomic number is 17?
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(A)
-1 and 7
36
The energy changes accompanying the addition of an electron to a gaseous atom is called?
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(C)
electron affinity
37
The molar ratio of oxygen to nitrogen in dissolved air is 2:1 whereas the ratio is 4:1 in atmospheric air because?
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(A)
nitrogen is less soluble than oxygen
38
An eruption pollution an environment with gas suspected to be H2S, a poisonous gas. A residue team should spray the environment with?
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(B)
moist SO2
39
In the experiment above, ammonium chloride crystals deposit on the walls of the tube is as a result of
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(C)
sublimation
40
Which of the gas laws does the above graph illustrate?
