NECO Chemistry Practical Questions and Answers 2022/2023 (Complete Solution)

NECO Chemistry Practical Questions and Answers 2022/2023 (Complete Solution)

2022 NECO Chemistry Practical Because they don’t comprehend the questions, many NECO applicants have trouble answering the NECO Practical Chemistry Alternatives A and B properly. I’ll demonstrate to you how to successfully complete the 2022 NECO Chemistry Practical problems and achieve a high score on your Chemistry exam.NECO Chemistry Questions and Answers 2022/2023 (Essay and Objectives)

Before tackling any questions, it is important to grasp the NECO Chemistry Practical marking scheme in order to present your answers in a style that will appeal to the examiner and help you receive high points.

Keep in mind that each process receives a grade. Therefore, be sure to follow all the steps in order to report and present your actual results.NECO Accounting Questions and Answers 2022/2023 (Essay and Objectives)

There will be two sessions on the Chemistry Practical Exam.general Chemistry inquiries, specifically:

Quantitative Analysis
Qualitative Analysis

Titration and ion test procedures are included. It will be required of you to conduct an experiment and to present your findings. What you observe will be very similar to the NECO Chemistry Specimen that was provided to your school.neco-chemistry-practical/

Note: Your chemistry teacher will provide you with your titration endpoint. Though not uniform across all schools, it falls within a range.

Use the endpoint elsewhere, please. Although it can differ from your center endpoint, you can still use the mathematical methods.

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NECO Chemistry Specimen 2020
CHEMISTRY PRACTICAL SPECIMEN:

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.

2. 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.
3. 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.

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

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.