Waec 2018 Chemistry Practical Expo 2018 Waec Chemistry Practical Questions And Answers Runz

Waec 2018 Chemistry Practical Expo

Here Is The Verified And Correct Waec 2018 Chemistry Practical Questions And Answers Expo / WASSCE 2018 Chemistry 3 (Practical) (Alternative A) Answers

Chemistry Practical Tuesday, 3rd April, 2018

Waec 2018 Chemistry Practical Expo

This Is How To Subscribe And Get Waec 2018 Chemistry Practical Questions And Answers Expo Before Exam Starts.

Where To Get Free Waec 2018 Chemistry Practical Questions And Answers Expo, Correct Waec Chemistry Practical Questions And Answers Runz.

(1a)
Volume of pipette used=25.0cm^3
TABULATE
Reading: Rough|1st|2nd|3rd
Final reading: 16.00|15.40|17.20|15.30
Initial reading: 0.00|0.00 |2.00 |0.00
Vol of acid used: 16.00|15.40|15.20|15.30

B contains 4.80g/250cm³
Hence x8 = 1000cm³
X = 4.80 × 1000/250 = 4.80 × 4 = 19.2gdm³

(1bi)
Hence molar concentration of B in moldm3
Mass Conc(8dm³) = molar Conc × molar mass
Molar Conc of B = mass conc/molar mass = 19.2gdm³/127gmol
Cb = 0.151moldm3

(1bii)
Concentration of A in moldm-³, CA is given by CAVA/CBVB = na/nb
Where CA = ?
VA = 15.30cm³,
na = 1
CB = 1.51moldm-³, VB = 25.0cm³, nb = 5
CA × 15.30/0.151 × 250= 1/5
Therefore CA = 0.151×25×1/15.30×5 = 3.775/76.50 = 0.049moldm-³
Hence Conc. Of A in moldm-³ = 0.049moldm-³

(1biii)
No of moles of Fe²+ in the volume of B pipetted
n= cv/1000 =
0.151×25.0/1000 =
3.775/1000
= 0.003775moles of Fe²+

2a)
-Observation-
part of the C dissolves,colourless filtrate salt

-Inference-
C is a mixture of soluble salt

2bi)
-observation-
white precipitate formed

-Inference-
Cl is present

2bii)
-Observation-
precipitate dissolves

-Inference-
Cl confirmed

2biii)
-Observation-
colourless gas evolved with characteristic choking smell, turns litimus paper blue

-Inference-
Gas is NH3

2c)
-Observation-
Residue dissolves liberating a colourless gas which turns lime water milky

-Inference-
gas is CO2
CO^2-3 present

3i)
A white precipitate of barium sulphate will be formed by the instant reaction between barium chloride and sulphuric acid.
BaCl2 + H2SO4 = BaSO4 + 2HCl

3b)
Iron sulfide reacts with hydrochloric acid, releasing the malodorous (rotten egg smell) and very toxic gas,hydrogen sulphide. FeS + 2 HCl → FeCl2+ H2S

3c)
The iron dissolves, releasing hydrogen and making an iron chloride solution:
Fe + 2HCl → FeCl₂ + H₂

Thanks For Visit Our Website, The Number One Exam Expo Runz Online Website 2018, Waec 2018, We Also Do Jamb-CBT Runz.