Home WAEC NECO NABTEB
JAMB CBT JUPEB IJMB Other Exams Main Website
Want To Contact Us? Click Here

Quick Contact

Click To Send Us SMS Now
Click To Chat Examrelief On WhatsApp

Latest Other Exams on Giditrends

2020 NECO Chemistry Questions and Answers
Other Exams November 18, 2020 • 7 days ago • No Comment Yet

WELCOME TO EXAMRELEIF 2020 NECO ANSWERS PAGE

KEEP REFRESHING THIS PAGE UNTIL THE QUESTIONS AND ANSWERS ARE FULLY UPLOADED

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

100% VERIFIED CHEMISTRY QUESTIONS

CLICK HERE

👑 2020 NECO VERIFIED CHEMISTRY ANSWERS👑

100% VERIFIED CHEMISTRY OBJ ANSWERS

1-10: BBDDADEBCA
11-20: BDEABDBCEE
21-30: DEEECCCCEC
31-40: ABDAADCAAB
41-50: EDEDAEADDD
51-60: DBEBABBADA

100% VERIFIED CHEMISTRY ESSAY ANSWERS

CLICK HERE AND HERE FOR SNAPPED ANSWERS

(1ai)
(i)graphite
(ii)diamond

(1aii)
(i)animal charcoal
(ii)carbon black

(1aiii)
(i)The property of elements are a periodic function of their atomic number
(ii)Elements are arranged in the periodic table according to the order of increasing in their atomic weight.

(1bi)
Periodicity can be defined as the trend or recurring variation in element properties with increasing atomic number.

(1bii)
using; mole = no; of atoms/avogadro’s constant
0.5=no; of atoms/6.023*10²³
no; of atoms = 0.5*6.02*10²³=3.012*10²³atom

(1ci)
Faraday’s first law of electrolysis state that the chemical deposition due to the flow of current through an electrolyte is directly proportional to the quantity of electricity (coulombs) passed through it.

(1cii)
2O²^- + 9^e —>2O²
no; of electron = 4
Q=20300C
G.M.V =22.4dm³.
F=96500C
Mole=Q/n,f
Mole=20300/4*96500
Mole=20300/386000
Mole=0.05mol
Recall; =vol/G.M.V
0.05=vol/22.4
vol=0.05*22.4
vol=1.12dm³

(1di)
Using H²SO⁴
H+ SO⁴^-¹
H+ OH^-
A+ Anode
OH —-> OH + e^-
2OH+(aq)+2OH(aq)—->2H²O(s)+O²(aq)

(1dii)
Tabulate
-Electrolyte- (I)teraoxosulphate(iv)acid
(II)Ester

-non electrolyte-
(III)phenol

(1ei)
(i)mercury

(1eii)
(I)no; of electron in Y =16
(II)no; of mass number =16+18=34
(III)sulphur
=========================

(2ai)
basicity can be defined as the number of replaceable hydrogen ion in an acid

(2aii)
(I) —> 3
(II) —> 1
(III) —> 2

(2bi)
(i)Concentration
(ii)Temperature
(iii)Pressure

(2bii)
(i)Light
(ii)Temperature
(iii)Nature of reactant

(2ci)
Tabulate
S/N; (I), (II)

Indicator; methyl orange, phenolphthalein

Colour in acid; red, colourless

Colour at end point; orange colourless

Colour in base; yellow, pink

Suitable for; strong acid and weak base, weak acid and strong base

(2cii)
(i)Nitrogen —> 1s²,2s²,2p³
(ii)Fluorine —> 1s²,2s²,2p⁵
(iii)Aluminum —> 1s¹,2s²,2p⁶,3s²,3p¹

(2di)
(I)Hydrogen gas is liberated
(II)The purple colour turns colourless
(III)It leads to the deposit of black residue of carbon

(2dii)
(i)It serve as immediate source of energy
(ii)it is used in the manufacture of sweets.
========================

(4ai)
(I)Burning requires heating while corrosion does not
(II)Boiling occurs at a certain temperature while evaporation occurs at all temperature

(4b)
A concentration solution can be defined as a solution formed when a large quantity of a substance dissolves in a little volume of water

(4bii)
(i)position of ion in electrochemical series
(ii)concentration ion
(iii)nature of electrodes

(4ci)
Al²(SO⁴)³=(27*2)+(32*3)+(16*12) =54+96+192=342glmol

(4cii)
Aluminum teraoxosulphate (iv)

(4ciii)
(i)Propane – 1,2,3,- triol
(ii)Potassium salt

(4di)
Tabulate.
-Soaples detergent-
(i)it does not form scum in hard water
(ii)they are non-biodegradale

-Soapy detergent-
(i)It firm scum in hard water
(ii)They are biodegradable

(4dii)
(i)RCOOH
(ii)ROH

(4diii)
V1=300cm³.
P1=760mmHg
P2=800mmHg,
V2=?
Using; V1*P1 =V2*P2
300*700=V2*300
V2=300*760/800
V2=228000/800
V2=285cm³

(4div)
Its change is +3

(4dv)
Al³^+ (Aluminum ion)
=========================

(5ai)
Coal and coke

(5aii)
(I)acidic — NO² nitrogen (iv) oxide
(II)neutral — NO nitrogen (ii) oxide

(5aiii)
HCOOH. H²SO⁴/H²O CO(g)

46g of HCOOH = 22.4dm³ of CO
600g of HCOOH = X
X= 600*22.4/46=2.92dm³ of CO(s) is produced.

(5bi)
(i)To standardize a solution of an acid or base
(ii)To determine the percentage purity and impurity of an acid of a base

(5bii)
(I)density
(II)solubility

(5ci)
FeCl²(s) + 2NaOH(aq) —-> 2NaCl²(aq) + Fe(OH)²(s)
The main product is sodium chloride and iron (II) hydroxide

(5cii)
(I)FeCl²
(II)iron (ii) chloride

(5di)
(I)it is slightly denser than air
(II)it is slightly soluble in water

(5dii)
Because on exposure to air of rust due to the formation of hydrated iron (iii) oxide. In other words rusting it changes to reddish brown flaky powder is formed with new properties and irrversable permanent change.
Fe(s) + 3O³(g)+ XH²O(s) —> 2Fe²O³ XH²O(s)

(5diii)
Mas of dry hydrogen =35g
Mass of dry hydrogen + oxygen vapour of a compound= 440g
Mass of organic vapour of the compound = 440g-35g=405g
V.D of the vapour =mass of vapour/mass of equal volume of H²
405/35 =11.51 ≅ 11.6
V.D = 11.6
R.m.m of the vapour =V.D *2
11.6*2=23.2
=====================

(6ai)
(I)Efflorescence
(II)Isotope
(III)Isomerism

(6aii)
Kipps apparatus

(6aiii)
(i)Temperature
(ii)Enthalpy change value

(6bi)
Polymerisation can be defined as the arrangement of smaller nuclei to form a large nuclei

(6bii)
(i)Addition polymerisation
(ii)Condensation Polymerisation

(6biii)
OH^- =4.583r10^⁵
Since [H^+] [OH]= 10^-¹⁴
[H^+] [4.583*10^-⁵]=10^-¹⁴
[H^+]=1*10^-¹⁴/4.583*10^-⁵
[H^+]=0.22*10^-⁹
[H^+]=2.2*10^-¹⁰moldm³
Since; PH= – logH^+
PH= – log¹⁰ 2.2*10^-¹⁰
PH=0.34+10
PH=10.34

(6ci)
(I) —-> carbohydrate
(II) —-> R-OH and R-CHO

(6cii)
(I)Brass composition; copper and zinc

-uses of brass-
(i)it is use in making hammers
(ii)it is used in application where low corrosion resistance is required.

(II)steel composition; iron and carbon

-Uses of steel-
(i)it is used on roofs
(ii)it is used as cladding for exterior walls

(6ciii)
(i)Fermentation
(ii)Preparation from ethene

(6iv)
This is because there are on molecules in that can accept protons

=====COMPLETED=====

Don’t Just Copy Alone, Drop your Comments, Share with your friends on Facebook & Twitter Using the below share buttons.
BEST OF LUCK

Click Here To Comment

Leave a Reply