Get 2020 Waec Gce Chemistry Obj and Theory Questions and Answers Hours To Exam

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Chemistry-Obj!
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11BCACCAABBB
21DBDCACBCAA
31CDACBBDBDD
41ACCBCDCDCC
[Pls Trace Your Objective Any Were You See The Option That The Correct Answers.]
Chemistry-Obj!
1 Involves the loss and gain of electrons
2 Polymerisation
3 Global warming
4 3
5 Zinc ions
6 +1.56V
7 Ethene
8 NH3
9 Propanol
10 28
11 Hydrolysis
12 d-orbital
13 Lowering the activation energy
14 Closeness between reactant particles
15 Remaining the same with time
16 Reaction vessel Fels cool during the reaction
17 Faster
18 Solvent extraction
19 Saturated Solution
20 2.75mol/dm³
21 Partially dissociates in aqueous solution
22 138g
23 HI
24 2.00cm³
25 hydrogen chloride
26 strong electrovalent bond between ions
27 is not ductile
28 Electrons
29 C2H4
30 Aluminium
31 0.010mol/dm³
32 PbCO3
33 Linear
34 HCL and HOCL
35 +1
36 Ionic bond
37 have relatively low ionization energy
38 sour to taste
39 I,III and IV only
40 chrometography
41 2.00 dm
42 mole of solvent in 1dm³ of solution
43 does not contain neutron
44 1s²2s²2p⁶
45 Ammonium chloride
46 IV
47 I,II and IV only
48 Quantum numbers of Electrons
49 -273⁰C
50 Mass number

(1a)
(i) butene
(ii) It decolourise KMnO4

(1aii)
On addition of bromine water to the compound in a test tube to an alkene in the cold, the brown solution is immediately decolonized which indicates it is unsaturated.

(1bii)
The HCOOH is converted to its corresponding alkanol due to the effect of KMnO4

(1c)
(i)Sigma bond is a chemical bond formed by the linear or co- axial over lapping of the atomic orbital of two atoms while a pi bond is a type of covalant bond that exists between atoms where the electron are on top and bottom of the axis connecting the nuclear of the joined atoms

(ii)sigma bond exist independently while pi bond does not

(iii)sigma bond are saying while pi bond are weak

(1d)
This is because propene can move readily undergo a free radial chain reaction.

(1e)
Substitution reaction their products is formed while addition reaction product is not formed

(1f)
(i)NH³—->H²O—->HF
(ii) because Fluorine is more electronegative than oxygen and oxygen is more electro negative than nitrogen

(1g)
(i) Polyethylene
(ii) it cause pollution

(1h)
Acid salt —> KHSO4
Normal salt —> KNO3
Double salt —> KAI(SO4)² 12H²O

(1i)
This is as a result of non poor nature

(1j)
10.

==========================================

2di.
Temperature
Pressure

2dii. The volume of a given amount of gas is inversely proportional to its pressure when the temperature is held constant (Boyle’s law). As the pressure on a gas increases, the volume of the gas decreases because the gas particles are forced closer together. Contrarily, as the pressure on a gas decreases, the gas volume increases because the gas particles can now move farther apart.

==========================================

(3ai)
¹³R, ⁸Q
¹³R=1s²,2s²,2p⁶,3s²,3p¹
⁸Q=1s²,2s²,2p⁴

(3aii)
¹³R=2,8,3
Valency of ¹³R is 3
⁸Q= 2,6
Valency of ⁸Q=2

(3di)
2H² SO4(aq)+4NaOH(aq)—>2Na² SO4(aq)+4H²O(s)

(3dii)
Sodium teraoxosulphate (iv) salt and water

(3diii)
The resulting solution NaSO4 is basic and will have no effect on litmus paper

(3div)
When heated to dryness it can be used as a dehydrating agent

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