Neco 2021 Chemistry Practical Questions and Answers, Neco Gce 2021 Chemistry Practical Answers, Neco Chemistry Practical Answers 2021 NECO CHEMISTRY PRACTICAL EXPO IS DONE AND DUSTED FOR MY SUBSCRIBERS ✅✅💯 DM ME NOW IF YOU ARE INTERESTED IN IT I REMAIN THE BEST ✅✅💯 Neco Chemistry Practical Specimen 2021 Neco Chemistry Practical 2022 Neco Chemistry Practical 2021 Date Neco Chemistry Question 2021 Neco Physics Practical 2021 Neco Timetable 2021 Wednesday 14th July 2021 Paper I: Practical – Chemistry 10:00am – 12:00noon ============================ CHEMISTRY PRACTICAL CHEMISTRY-PRACTICAL (1a) Tabulate Volume of pipette used=25cm3. Indicator used= Methyl orange Under Titration, Rough, 1st, 2nd, 3rd, Final burette reading; |25.00| |23.40| |23.50| 23.60| Initial burette reading; |0.00| |0.00| |0.00| |0.00| Volume of A used; |25.00| |23.40| |23.50| |23.60| (1ai) Average volume of Acid used=23.40+23.50+23.60/3 =70.5/3=23.50cm3 (1aii) This is because it is a reaction between a weak acid and strong base (1aiii) A funnel should be used while transferring the acid into the burette. (1bi) Conc of A in mol|dm³ =? Conc of A in g|dm³ = 12.75g|dm³ Molar mass of A, NaHSO⁴ = 23+1+32+64 =120g|dm³ From. Conc(mol/dm³) = conc(g/dm³)/molar mass Conc =12.75/120 Conc =0.106mol/dm³ (1bii) Con of B in mol/dm³ =? Ca =0.106, Cb =? Va =23.50cm³, Vb =25.00cm³ na=1 , nb=1 From; CaVa/CbVb=na/nb Cb=CaVanb/Vbna Cb=0.106*23*50*1/25.00*1 Cb=2.5/25 Cb=0.1mol/dm³ (1biii) Conc of B in g/dm³=? Molar mass of B , NaOH=23+16+1=40g/mol From; conc(g/dm³)=conc(mol/dm³)*molar mass =0.1*40 =4.0g/dm³ (1biv) Mass of salt formed =? Recall mole of NaHSO⁴=? From; mole =con(mol/dm³)*vol(cm³)/1000 Mole=0.106*23.50/1000 Mole=0.0025mol of NaHSO⁴ By proportion 1mol of NaHSO⁴ produce 1mol of Na²SO⁴ 0.0025mol of NaHSO⁴ will produce X mol of Na²SO⁴ X=0.0025*1=0.0025mol of NaSO⁴ Molar mass of Na²SO⁴=(23*2) + 32 + (16*4) =46+32+64 =142g/mol Recall; mole =mole/molar mass Mass =mole * molar mass Mass =0.0025*142 Mass =0.36g of Na²SO⁴ ==================================== (2a) TEST C + 5cm³ of distilled water OBSERVATION It dissolve completely INTERFERENCE C is a soluble salt (2bi) TEST Solution + NaOH + Heat OBSERVATION Effervescence occurs in which a colourless gas with pungent smell and turns red litmus paper to blue is given off. INFERENCES NH³ gas from NH⁴+ is present (2bii) TEST Stirring rod of HCL + gas given off OBSERVATION a gas which gives a pop sound is given off INFERENCES H² is present (2ci) TEST Solution C + drops of BaCL² OBSERVATION a white precipitate is formed INFERENCES CO²^-3, SO²^-4, SO²^-3, May be present. (2cii) TEST Solution in C(i) + dil HCL OBSERVATION the white precipitate dissolve is dil HCL and effervescence occurs in which a colourless and odourless gas which turns blue litmus red and lime water milky is given off INTERFERENCE CO² gas from CO²^3- confirmed ==================================== (3a) (i)Ca²+ (ii)Pb²+ (3bi) concentrated acid can be defined as an acid formed when a large quantity of an acid dissolve in a small or little volume of water. (3bii) A strong acid is defined as a type of acid that ionize completely in a solution (3c) Activated charcoal is used as an adsorbent material (3d) (i)Reddish – Brown (ii) I – red, II – brown. ==================================== Completed!. Promise Fulfilled.