SH MOBILE LOGO
Home | Waec | Neco | Jamb | Nabteb | G.c.e | Time Table | Education | Verifications | Chat | Payment | Others|

Fast & Easy Contact
examgoals: 08074125006 ||gidiclass: 08074125006

jamb

2021 JAMB QUESTIONS AND ANSWERS | 2021 JAMB EXPO


(SCORE 250+ IN YOUR RESULT).
CLICK HERE TO SUBSCRIBE NOW
Our Jamb Cbt Runs Answers is 100% Legit



Our Jamb Cbt Runs Payment Close Soon, Start Making Your Payment To Be Among Candidates to Score 250+.



WAEC SUBSCRIPTION PAYMENT
ALL SCIENCE ANSWERS (#4000)
ALL ART ANSWERS (#4000)
SCHOOL OWNERS (CHAT ME UP)
All Our Answers are 100% Legit and Trusted.
Send your: Mtn-card, Subject, Phone number and Exam Type
To 08074125006





Exams QuickLink

CLICK HERE FOR OUR ANSWERS PAGE

« | »

WAEC 2020 Chemistry Practical Question And Answer

Posted by on August 17th, 2020


Message Us On WhatsApp (CLICK HERE)
Text Message Us SMS (CLICK HERE)

How to Get 2020 WAEC  CHEMISTRY PRACTICAL Question Paper.

Follow the steps below to get your waec CHEMISTRY questions and answers 1 hours before your exam time.

2020 WAEC-CHEMISTRY-PRACTICAL ANSWERS
=================================
(1a)
In a tabular form

Burette Reading|1st reading|2nd reading|3rd reading
Final |15.25|0.00|45.79|
Initial|0.00||15.25|30.53|
Volume of acid used |15.25|15.28|15.26

Average volume of acid used = 15.25 + 15.26/2
= 15.255cm³
=15.26cm³

(1bi)
Given: Mass of conc of A = 5g/500cm³ = 5g/0.5dm³
Ca = 10g/dm³

A is HNO3
Therefore; Molar mass = 1+14+(16×3)
= 15+48
=63g/mol

Molarity of A = gram conc/molar mass
Ca = 10/63 = 0.1587mol/dm³

(1bii)
Using CaVa/CbVb = nA/nB
With reacting equation:
HNO3 +NaOH–>NaNO3 + H2O
nA = 1, nB = 1
0.1587×15.26/Cb×25.00 = 1/1
25Cb = 0.1587×15.26
CB = 0.1587×15.26/25
CB = 0.09687mol/dm³

(1biii)
B is NaOH
Molar mass = 23+16+1
=40g/mol
Conc of B in g/dm³ = molarity×molar mass
=0.09687×40
=3.8748g/dm³

(1biv)
No of moles present in 250cm³ of NaOH is
= molar conc. × volume
= 0.09687 × 250/1000
= 0.0242 moles

Mole ratio of NaOH and NaNO3 is 1:1
No of moles of NaNO3 which reacted is 0.0242
Mass of NaNO3 formed = molar mass × no of moles
= 85 × 0.0242
=2.057grams
=================================
(2a)
TEST
C + burning splint

OBSERVATION
Sample C bursts into flame
It burns with non-smoking blue flame, without soot.
Colourless gas that turns wet with blue litmus paper faint red and turns lime water milky is present

INFERENCE
C is volatile and flammable. The gas is CO2 from combustion of a saturated organic compound.

(2bi)
TEST
C + distilled water + Shake

OBSERVATION
Clear or colourless solution is observed

INFERENCE
C is miscible with water

(2bii)
TEST
C + Acidified K2Cr2O7

OBSERVATION
Orange color of K2Cr2O7 Solution turns pale green and eventually pale blue on cooling

INFERENCE
C is a reducing agent

(2c)
TEST
D + C + 10% NaOH + Shake

OBSERVATION
D dissolve slowly in C and produces reddish brown solution

Reddish brown solution turns yellow precipitate. The precipitate has an antiseptic odour

INFERENCE
D is soluble in organic solvents

Ethanol, ethanal or a secondary alkanol is present

(2d)
Compound belongs to the class of secondary alkanol
=================================
(3ai)
Zinc nitrate

(3aii)
2 Zn(NO 3 )2 —–>2 ZnO + 4 NO 2 + O 2

(3aiii)
It turns white when cold from it yellow colour when it was hot

(3b)
Pipette / measure 50.0cm3 of the stock solution into a 250
cm3 volumetric flask (containing some distilled water). Shake / swirl and add more distilled water until the mark is reached.

(3c)
Al2(SO4)3 – turns blue litmus red
=================================
Completed!!!!!!!

Post Views: 603

RECOMMENDED POST FOR YOU

» NABTEB GCE 2021/2022 QUESTION, SOLUTION & EXPO ANSWER » Neco 2020 English Language Objective, Essay, Oral Questions & Answers Now Available » NSUK Postgraduate Admission List, 2019/2020 Out » LASU Acceptance Fee Payment For 2019/2020 Session Has Commenced » FUGashua Supplementary Post-UTME 2019: Cut-off mark, Eligibility and Registration Details

OR


CLICK TO DROP YOUR COMMENT

Share this post with your Friends on



3 Comments

  1. I like this grouo

    by Prince mathew on Aug 31, 2020 at Reply

  2. chemistry practical question and answer

    by onu agwu olughu on Aug 18, 2020 at Reply

  3. waec answers

    by adams magaji on Aug 17, 2020 at Reply

Leave a Reply

Your Name:

Your Message:





Go Back To The Top


« | »


Looking for something? Search below






LIKE US ON FACEBOOK