Latest Chemistry Practical NECO 2022 Questions And Answers

Are you preparing for the Chemistry Practical NECO 2022 exam? Look no further! In this comprehensive guide, we will provide you with all the essential information and tips to help you excel in this important examination.

Chemistry Practical NECO 2022 Questions & Answers Exam

The Chemistry Practical NECO 2022 exam is a crucial part of the NECO (National Examination Council) Senior Secondary Certificate Examination (SSCE) for students in Nigeria. This practical test assesses your understanding of various chemistry concepts and your ability to perform experiments accurately.

Requirements:
(a) One burette (50cm³)
(b) One pippete (20cm³/25cm³). However, all
participating students in a center must use pipettes of the
same volume.
(c) The usual apparatus and reagents for
qualitative work including:
(i) Dilute sodium hydroxide solution
(ii) Dilute ammonia solution
(iii) Dilute hydrochloric acid
(iv) Barium chloride solution
(v) Distilled water
(vi) Red and Blue litmus paper
(vii) Phenolphtalein
(d) Methyl orange
(e) One boiling tube
(f) Five test tubes
(g) Filtration apparatus
(h) Source of heat
Each candidate should be provided with the following: Labelled An, Bn, Cn, where ‘n’ represents
candidate’s serial number.
(a) 150cm³ of chloride acid solution in a bottle
labelled “An”. The acid solution which should
be the same for all candidates will contain
3.4cm³ of the concentrated hydrochloric acid
per dm³ solution.
(b) 150cm³ of sodium hydroxide solution in a
bottle labelled “Bn”. The solution which should
be the same for all candidates will contain
4.0g of sodium hydroxide per dm³ of solution.
(c) One spatulaful of copper (ii)
tetraoxosulphate (vi) salt in a specimen bottle
labelled “Cn”.

The following exam questions are only for preparation and not for the 2021 Chemistry Expo.

The size of your pipette and all of your burette readings, both initial and final, must be recorded, but no detailed description of the experimentation process is necessary. You must complete all calculations in your booklet.

A is O.200 moldm3 of HCI. C is a solution containing 14/3g of Na2CO3. x H2O in 500 cm3 of solution. (a) Put A into the burette and titrate it against 20.0 cm3 or 25.0 cm3 portions of C using methyl orange as indicator. Repeat the titration to obtain Consistent titre values. Tabulate your results and calculate the average volume of A used. The equation for the reaction is: Na2CO3 x H2O + 2HCL(aq) → 2NaCI(aq) + CO2(g) + (x+1) H2O(I).
(b) From your results and the information provided. Calculate the: (i) concentration of C in moldm-3; (ii) concentration of C in gdm-3; (iii) molar mass of Na2CO3, xH2O; (iv) the value of x in Na2CO3 xH2O. [H = 1.0; C=12.0; O = 16.0; Na =23.0]

Strict obedience to the instructions, accurately recorded observations, and reliable inferences will all result in credit. The booklet must be filled out in full, in ink, at the time of each test, observation, and influence.

  1. F is a mixture to two inorganic salts. Carry out the following exercise on F. record your observation and identify any gas(s) evolved. Mention the conclusions you draw from the result of each test. (a) Put all of F in a beaker and add about 10cm3 of distilled water. Stir well and filter. Keep the filtrate and the residue. (b)(i) To about 2cm3 of the filtrate, add NaOH(aq) in drops and then in excess (ii) To another 2cm3 portion of the solution, add a few drops of NHO3(aq)followed by few drops of AgNO3(aq). (d)(i) Put all the residue into a clean test-tube and add NHO3(aq) followed by few solution from 2(d)(i) add NaOH(aq) in drops and then in excess.
  2. List the findings that would result from the following laboratory experiments: (i)adding methyl orange to a solution of lime juice (ii) A solution of iron (III) chloride is bubbled through with hydrogen sulfide gas; (iii) an acidified solution of KMnO4 is bubbled through with sulphur (IV) oxide gas; and (iv) a solution of K2CO3 is added with ethanoic acid.

Free Neco 2023 Chemistry Expo

CHEMISTRY PRACTICALS ANSWERS

Indicator                                 =          Methyl Orange
Volume of the base used        =          25.00cm3

Titration Rough Titre 1st Titre 2nd Titre 3rd Titre
Final Burette readings cm3 24.70 24.80 24.70 24.90
Initial Burette reading cm3 0.00 0.00 0.00 0.00
Volume of acid used cm3 24.70 24.80 24.90 24.90
Average Titre  value           =          1st + 2nd + 3rd/3

=          24.80 + 24.70 + 24.90/3

=          24.80cm3

Alternatively 2 concordant titres can be used to calculate average titre.

Equation of the reaction: Na2CO3 XH2O + 2HCI(aq) → 2NacI(aq) + CO2(aq) + (x+1)H2O(I)

CAVA/CBVB     =  nA/nB

CA = Molar concentration of HCI(aq) in moldm3

VA = Volume of acid used in cm3 = 24.80cm3

CB = Molar concentration of Na2Cu3 xH2O in moldm3

nA = 2

nB = 1

(b)(i) concentration of C in moldm-3 = ? From the equation of reaction:

CAVA/CBVB     =  nA/nB

CA = 0.200 moldm3     VA = 24.80cm3

CB = ?                          VB = 25.00cm3

Substitution of known values

0.200 x 24.80/ CB x 25.00 = 2/1

CB = 1×0.200×24.80/2×25.00

CB­ = 0.0992 moldm-3

(ii) Concentration of C in g dm-3 = ?

500cm2 → 14.3 g

1000cm3 →14.3/500 x 10002 g

= 28.6 g dm-3

(iii) Molar mass of Na2CO3 xH2O

Molar concentration in moldm-3 = concentration in g dm-3 / molar mass

Therefore: Molar mass g mol-1 = conc in g dm-3 / molar concentration in moldm-3

= 28.6 g dm-3/0.0992 moldm-3

= 288.3065

Approximately 288 g mol-1

(iv) Value of x in Na2CO3 xH2O?

[H = 1.0, C = 12.0, O = 16.0, Na = 23.0] Na2CO3 xH2O = 288

 

2(23) + 12 + 3 (16) + x (2(I) + 16) = 288

46 + 12 + 48 + 18x  = 288

106 + 18x        = 288

18x      = 288

18x      = 182

x       = 182/18

x       = 10.11

x approximately 10

Chemistry Practical NECO 2022
Chemistry Practical NECO 2022 question one
Chemistry Practical NECO 2022

2. Test Observation inference
(a) F + distill water + stir + filter
After filtration, a colorless and odorless gas called effervescence (bubbling) is produced, along with a pale blue or colorless filtrate and green residue.
(b)(i) Filtrate + NaOH(aq) in drops then in excess White precipitate formed   Precipitate insoluble in excess NaOH(aq) Ca2+/Pb2+   Ca2+ present
(b)(ii) Filtrate + NH3(aq) in drops then in excess No visible reaction   No visible reaction OR Ca2+ present   Ca2+ confirmed
(b)(i) Filtrate + NaOH(aq) in drops then in excess Blue gelatinous precipitate formed   Precipitate insoluble in excess     Cu2+  is present
(b)(ii) Filtrate + NH3(aq) in drops then in excess Pale (light) blue gelatinous precipitate formed   Precipitate dissolves to form a deep blue solution Cu2+     Cu2+  is confirmed
(c) Filtrate + NHO3(aq) + AgNO3(aq) No visible reaction No gas involved White precipitate formed CuI-  is present
(d)(i) Residue + HNO3(aq) Effervescence occurs, colourless and odourless gas evolves that turns blue litmus paper to red and turns lime water milky CO2(g) CO32- present
(d)(ii) Solution from 2(d)(i) + NaOH(aq) in drops then in excess Blue precipitate formed   Precipitate insoluble in excess NaOH(aq) Cu2+    Cu2+   present

3 (a)(i) Solution of lime juice turns to pink or red. (ii) The FeCI3 solution changes colour from brown to green and a yellow deposit. (iii) The purple colour of the KMnO4 solution turns colourless or decolourised. (iv) The solution of K2CO3 reacts with the addition of ethanoic acid to evolve a colourless, odourless gas with bubbling of effervescence.

Tips for Success

1. Familiarize Yourself with the Lab Equipment

Before the exam, make sure you are well-acquainted with the laboratory equipment you’ll be using. Practice using them to ensure you can handle them confidently during the practical.

2. Review the Experiment Procedures

Carefully go through the experiment procedures provided in your syllabus. Understanding each step is essential for accurate execution during the exam.

3. Safety First

Always prioritize safety in the laboratory. Familiarize yourself with safety guidelines and procedures to prevent accidents.

4. Practice, Practice, Practice

The key to success in the Chemistry Practical NECO 2022 exam is practice. Repeatedly perform the experiments to build your confidence and accuracy.

Frequently Asked Questions (FAQs)

Q1: What should I do if I encounter an unexpected result during the experiment? A1: If you encounter unexpected results, don’t panic. Analyze the situation, check your procedure, and make adjustments as necessary. Document any deviations in your observations.

Q2: Are there any specific safety precautions I should be aware of? A2: Yes, there are several safety precautions you should follow in the laboratory. Always wear appropriate safety gear, handle chemicals with care, and follow established safety guidelines.

Q3: How should I present my results in the practical report? A3: Your practical report should be clear and well-structured. Include a title, purpose, procedure, observations, calculations, and conclusions.

Conclusion

Success in the Chemistry Practical NECO 2022 exam is achievable with the right preparation and mindset. Make sure to practice extensively, prioritize safety, and familiarize yourself with the exam format and procedures. With dedication and hard work, you can excel in this important examination.

Leave a Comment