NABTEB GCE 2017 CHEMISTRY Practical Questions and Answers – Nov/Dec Expo

NABTEB GCE 2017  CHEMISTRY PRACTICAL QUESTIONS AND ANSWERS SOLUTIONS Nov/Dec Expo

 

Exam Time: Wed 15th Nov 2017
Chemistry(Alternative to practical)
9.00am-11.00am

=-=-=-=-=-=-=-=-=-=-==-=-=-=-=-=-

 

NOTE: OUR ANSWERS ARE 100% CORRECT AND LEGIT,SUBSCRIBE AND GET UR ANSWERS… DONT COME FOR FREE ANSWERS.. PAY AND ENJOY…

OUR 2018 JAMB EXPO SUBSCRIPTIONS HAS STARTED.. EARLY PAYMENT ATTRACTS GOOD GRADES…TELL UR FRIENDS… 

 

 

NABTEB GCE PRACTICAL CHEMISTRY ANSWERS FROM EXAMHOT.COM
–=-=-=-=-=-=-=-=-=-=-==-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

 

 

PRACTICAL CHEMISTRY THEORY:
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

1a )
i ) burette
ii) pipette
iii ) conical flask
iv ) beaker

1bi )
i ) application of 2 to 3 drops of indicator to the base
ii) titration( rush) of acid into base sonutaneously and swirled ( shaked )

1bii)
weak acid vs strong base = phenophthalein

1ci )
molarity of B = mass concentration / molar mass = 2. 20/ 0. 25/ 40
molarity of B = 8.8 / 40
molarity of B = 0.220 moldm ^ -3

1cii )
CaVa / CbVb = Ca = CbVbna / Vanb = Ca = 0. 22* 25 * 1/ 24 .60 * 2= 5. 5/ 49. 2
Ca = 0 .11178
Ca = 0 .112 mold ^ -3

1ciii )
molar mass = mass concentration / molar concentration = 3. 90/ 0. 112
molar mass of H 2X = 35gmol ^ – 1
hence H 2X = 35 = 2 + X = 35
X = 35- 2
K = 33
R . A. Mx = 33 gmol ^ – 1

 

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

2ai )
the ethanedioic acid turns pink or red on adding methyl organe to it

2aii )
the hydrated form is efflorescence- when expsosed to air it effloresces and turns yellow due to atmospheric oxidation to basic iron ( iii ) teltraoxosulphate ( iv )

2aiii )
Pb ( No 3) ( aq ) +H 2SO 4( aq ) – — – -> PbSO 4( aq ) +2HNO 3
lead ( ii) tetraoxosulphate ( vi ) is formed which is insoluble in water

2aiv )
Zn( s ) + CUSO 4( aq ) — – — > ZnSO 4( aq ) + CH ( s )
copper metal is deposited as zinc displaced copper

2bi )
CaC 2( s ) + 2H 2O ( s ) – — – — > C 2H 2( g) + Ca ( OH ) 2 ( aq )

2bii)
the reaction is exothermic and hence it should be performed on a leap of sand inside the flask to prevent the flask from cracking

2biii )
Impurities – Phospine ( PH 2) hydrogen sulphide ( H 2S ) and ammonica ( NH3)
Reagent : Copper ( II ) tetraoxosulphate ( vi ) solution

2biv )
i ) because it is slightly less dense than air
ii) because it is unstable and may explode on compression to a liquid

2bv)
the reaction with sliver trioxonitrate( v) dissolved in alcohol may be used to distinguish alkenes from alkyness as no reaction in alkene . While terminal alkynes form a white precipitate

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

3ai )
i ) it is not used because it react with the gas as thus 2NH3( aq ) + H 2SO 4( aq ) — – — > ( NH4) 2SO 4( s )

3aii )
ammonia is very soluble in water at s .t . p due to readness with which forms hydrogen bond with water ( NH3. H 20)

3aiii )
this is to prevent trickling back of gas and mixture of gas with water formed during reaction

3b)
i ) by grinding to powder to increase surface area of contact
ii) by increasing the temperature of liquid in some cases or lower the temperature as the case may be

3ci )
FbC 03( s ) Heat – — – > Pbo ( s ) + Co 2( g)
Pb ( N 03) 2( s ) Heat – – -> pb( s ) + 2N 02 ( g) + 02( g)

3cii )
NH4Cl turns moist red litmus blue
NaCl Neutral to litmus paper
( No Reaction is observed )

3d)
y= FeSo 4- -> Fe ^ 2+ + So 4 ^ 2-
Anions: So 4^ 2 – , So ^ 3 – , S ^ 2-

3ei )
F = Wire Gauze
E= drying agent e ,g silical gel , calcium oxide, phosphorus ( v) oxide amnonia,fused calcium chloride

3eii )
it is used in keeping and drying solids in an atmosphere that is dry and free of dust
3eiii )
it is always greased in order to make it air tight and hence exclude atmospheric moisture.

 

 

 

Mr Hillz cares

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

COMPLETED..

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

About Mr Hillz 961 Articles
Am a simple guy who has the good of students at heart... Without trust we can't move together