NECO CHEMISTRY PRACTICAL ANSWERS 2021
Here is the neco chemistry practical answers for 2021. More answers will be posted, check back in few minutes and refresh.
Chemistry practical answers 2021
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|
Average volume of Acid used=23.40+23.50+23.60/3 =70.5/3=23.50cm3
This is because it is a reaction between a weak acid and strong base
A funnel should be used while transferring the acid into the burette.
Conc of A in mol|dm³ =?
Conc of A in g|dm³ = 12.75g|dm³
Molar mass of A, NaHSO⁴ = 23+1+32+64
Conc(mol/dm³) = conc(g/dm³)/molar mass
Con of B in mol/dm³ =?
Ca =0.106, Cb =? Va =23.50cm³, Vb =25.00cm³
na=1 , nb=1
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
Mass of salt formed =?
Recall mole of NaHSO⁴=?
From; mole =con(mol/dm³)*vol(cm³)/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)
Recall; mole =mole/molar mass
Mass =mole * molar mass
Mass =0.36g of Na²SO⁴
C + 5cm³ of distilled water
It dissolve completely
C is a soluble salt
Solution + NaOH + Heat
Effervescence occurs in which a colourless gas with pungent smell and turns red litmus paper to blue is given off.
NH³ gas from NH⁴+ is present
Stirring rod of HCL + gas given off
a gas which gives a pop sound is given off
H² is present
Solution C + drops of BaCL²
a white precipitate is formed
CO²^-3, SO²^-4, SO²^-3, May be present.
Solution in C(i) + dil HCL
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
CO² gas from CO²^3- confirmed
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.
A strong acid is defined as a type of acid that ionize completely in a solution
Activated charcoal is used as an adsorbent material
(i)Reddish – Brown
(ii) I – red, II – brown.