Today's examination papers
Tuesday 31st May.
Paper I: Practical Chemistry 10:00am – 12pm
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(A) ONE BURETTE (50cm³)
(B) ONE PIPETTE (20cm³) OR
25cm³)
NOTE:ALL CANDIDATES IN A
CENTRE MUST USE PIPETTES OF
THE SAME VOLUME.
(C) THE USUAL OF THE SAME FOR
FILTRATION
(D) THE USUAL APPARATUS AND
REAGENTS FOR QUALITATIVE
WORK INCLUDING:
(i) RED AND BLUE LITMUS PAPER
(ii) AQUEOUS AMMONIA
(iii) DILUTE HNO³-
(iv) DILUTE SILVER
TRIOXONITRATE (V)
SOLUTION
(v) AQUEOUS SODIUM
HYDROXIDE
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(vi) DILUTE HCI
(vii) POTASSIUM THIOCYNATE
SOLUTION
(viii) POTASSIUM
HEPTAOXOCHROMATE
(VII)
SOLUTION
(ix) BARIUM CHLORIDE
SOLUTION
(E) SPATULA
(F) FILTRATION APPARATUS
(G) ONE BEAKER
(H) ONE BOILING TUBE
(I) FOUR TEST TUBE
(J) PHENOLPHTHALEIN
INDICATOR
(K) METHYL ORANGE INDICATOR
(I) MATHEMATICAL TABLE/
CALCULATOR
(M) WASH BOTTLE CONTAINING
DISTILLED/ DEIONIZER WATER
Tuesday 31st may 2016
CHEMISTRY PRACTICAL 10:00am-12:00pm
+++++++++++++++++++++++++++++++++++
1)
TABULATE
Burette reading(cm^3):Final reading(cm^3),Initial reading(cm^3),Volume of acid used(cm^3)
Rough:26.00,2.00,24.00
1st reading:25.50,1.00,24.50
2nd reading:24.50,0.00,24.50
3rd reading:24.50,0.00,24.50
Average volume of acid used
=1st+2nd+3rd/3
=24.50+24.50+24.50/3
=24.50cm^3
Concentration of A mol/dm^3=Conc g/dm^3/molar mass
Molar mass of H2SO4 =2(1)+32+4(16)
=98g/dm^3
Concentration mol/dm^3=4.90/98
=0.05mol/dm^3
i)Using CaVa/CbVb=na/nb
(0.05*24.50)/Cb*25)=1/2
Cb=(0.05*24.50*2)/25
=0.098mol/dm^3
ii)Concentration of B in g/dm^3=Conc in mol/dm^3*molar mass
Molar mass of NaOH=26+16+1=40g/mol
=0.098mol/dm^3*40g/mol
=3.92g/dm^3
iii)percentage purity of B=Concentration of pure/concentration of impure *100%
=3.92/4*100%
=98%
Therefore percentage of impurity of B =100-98%
=2%
1)
volume of pipette used =25.0cm^3
indicator used =methyl orange
burette reading|rough| 21.50|0.00|21.50|
final burette readings (cm^3)|1st|21.20| 0.00. 21.20|
initial burette reading(cm^3)|2nd|31.20|10.00| 21.20|
volume of a used (cm^3)|3rd|41.20|20.00|21.20|
average volume of a used =(21.20+21.20+21.20)cm^3/3
=63.60cm^3/3
=21.20cm^3
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equation of the reaction
H2SO4(aq) + 2NaoH(aq)+2H2O(s)
nA=1,nB=2
A=4.90gldm^3 H2SO4
molar mass H2SO4
=(1*2)+32+(16*4)
=2+32+64
=98gmol^-1
molar conc A=mass con A/molar mass A
=4.90gldm^3/98glmol
=0.05moldm^3
CAVA/CBVB=nA/nB
0.05moldm^3*21.20cm^3/CB*25.0cm^3=1/2
0.05moldm^3*21.20*2=CB*25.0
CB=0.05molldm^3*21.20*2/25.0
CB=0.0848moldm^3
in mass conc B =Molar B*MolarBmass
B=NaoH
=23+16+1
=40gmol-^3
mass conc B =0.0848moldm^3 * 40gmol
mass con B = 3.392gldm^3
% mass of impusx 100%/total mass of implusty
mass of implus =(4.0-3.392)gldm^3
=0.608gldm^3
%impurity =0.608gldm^3*100%/4.0gldm^3
=15.2%
3ai)
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Drawing lebel
-lid
-sticky tape(to hold paper)
-choroatographic paper
-gas jar
-applied spot of solute mixture
-ion
3aii)
principle of dillution, C1 V1=C2 V2
2.0molldm^3*40
3bi)
ethanol—->ethanoic (acid)—->trioxonotrate(v) (acid)
3bii)
indicators are used to determine the end point of the reaction and to test the acidity or alkalinity of a solution
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CHEMISTRY PRACTICAL ANSWERS...
2ai)
Observation:The salt sample dissolves completely
Inference:C is a mixture of soluble salts
2aii)
Observation:White precipitate insoluble in excess NaOH(aq)
Inference:Ca^2+ present
2aiii)
Observation:No visible reaction
Inference:Ca^2+ is present
2aiv)
Observation:Brownish fume is produced
Inference:NO2(g) form, NO3^- present
2av)
Observation:Formation of brown gas which forms a ring junction with FeSO4
Inference:NO2 form, NO3^- confirmed
2bi)
Observation:D dissolves completely. Formation of dirty green precipitate insoluble in excess NaOH(aq)
Inference:D is soluble in salt, Fe^2+ present
2bii)
Observation:Formation of a white precipitate.precipitate remains insoluble in HCl(aq)
Inference:SO3^2-,CO3^2-,SO4^2- present,SO4^2- confirmed
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(3ai)
Drawing lebel
-lid
-sticky tape(to hold paper)
-choroatographic paper
-gas jar
-applied spot of solute mixture
-ion
3aii)
principle of dillution, C1 V1=C2 V2
2.0molldm^3*40
3bi)
ethanol---->ethanoic (acid)---->trioxonotrate(v) (acid)
3bii)
indicators are used to determine the end point of the reaction and to test the acidity or alkalinity of a solution
1)
volume of pipette used =25.0cm^3
indicator used =methyl orange
burette reading|rough| 21.50|0.00|21.50|
final burette readings (cm^3)|1st|21.20| 0.00. 21.20|
initial burette reading(cm^3)|2nd|31.20|10.00| 21.20|
volume of a used (cm^3)|3rd|41.20|20.00|21.20|
average volume of a used =(21.20+21.20+21.20)cm^3/3
=63.60cm^3/3
=21.20cm^3
equation of the reaction
H2SO4(aq) + 2NaoH(aq)+2H2O(s)
nA=1,nB=2
A=4.90gldm^3 H2SO4
molar mass H2SO4
=(1*2)+32+(16*4)
=2+32+64
=98gmol^-1
molar conc A=mass con A/molar mass A
=4.90gldm^3/98glmol
=0.05moldm^3
CAVA/CBVB=nA/nB
0.05moldm^3*21.20cm^3/CB*25.0cm^3=1/2
0.05moldm^3*21.20*2=CB*25.0
CB=0.05molldm^3*21.20*2/25.0
CB=0.0848moldm^3
in mass conc B =Molar B*MolarBmass
B=NaoH
=23+16+1
=40gmol-^3
mass conc B =0.0848moldm^3 * 40gmol
mass con B = 3.392gldm^3
% mass of impusx 100%/total mass of implusty
mass of implus =(4.0-3.392)gldm^3
=0.608gldm^3
%impurity =0.608gldm^3*100%/4.0gldm^3
=15.2%
*note your school will give a value(end point). Your value should not be more or less than +/- 0.2 to what is being given*
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Tuesday 31st May.
Paper I: Practical Chemistry 10:00am – 12pm
Content will be available after 10 minutes, so re- visits this page
At Naijacomms.com
Content (protected)
This is for paid package
How to subscribe
Direct Mobile: N700 MTN CARD.
Or Pay a one-time fees of N3000 for all subjects To Our bank Account below
Forward Your Name, MTN PIN, Subject Name, Phone number to: 07061837436
we will send the Obj & Essay directly to your submitted phone numbers 9hours before the exam day
Note that for those who can't afford to pay you are advice to go for the free packages, Answers are pasted here 10 minutes after the exam begins,
For content: Practical Chemistry
Questions & Answers to appear, you have to share this page to 10 friends on WhatsApp, using the WhatsApp button below this post, and share to Facebook just once using the Facebook button below this post. After doing this the Practical Chemistry Questions & Answers would automatically appear.
(A) ONE BURETTE (50cm³)
(B) ONE PIPETTE (20cm³) OR
25cm³)
NOTE:ALL CANDIDATES IN A
CENTRE MUST USE PIPETTES OF
THE SAME VOLUME.
(C) THE USUAL OF THE SAME FOR
FILTRATION
(D) THE USUAL APPARATUS AND
REAGENTS FOR QUALITATIVE
WORK INCLUDING:
(i) RED AND BLUE LITMUS PAPER
(ii) AQUEOUS AMMONIA
(iii) DILUTE HNO³-
(iv) DILUTE SILVER
TRIOXONITRATE (V)
SOLUTION
(v) AQUEOUS SODIUM
HYDROXIDE
www.naijacomms.com
(vi) DILUTE HCI
(vii) POTASSIUM THIOCYNATE
SOLUTION
(viii) POTASSIUM
HEPTAOXOCHROMATE
(VII)
SOLUTION
(ix) BARIUM CHLORIDE
SOLUTION
(E) SPATULA
(F) FILTRATION APPARATUS
(G) ONE BEAKER
(H) ONE BOILING TUBE
(I) FOUR TEST TUBE
(J) PHENOLPHTHALEIN
INDICATOR
(K) METHYL ORANGE INDICATOR
(I) MATHEMATICAL TABLE/
CALCULATOR
(M) WASH BOTTLE CONTAINING
DISTILLED/ DEIONIZER WATER
Tuesday 31st may 2016
CHEMISTRY PRACTICAL 10:00am-12:00pm
+++++++++++++++++++++++++++++++++++
1)
TABULATE
Burette reading(cm^3):Final reading(cm^3),Initial reading(cm^3),Volume of acid used(cm^3)
Rough:26.00,2.00,24.00
1st reading:25.50,1.00,24.50
2nd reading:24.50,0.00,24.50
3rd reading:24.50,0.00,24.50
Average volume of acid used
=1st+2nd+3rd/3
=24.50+24.50+24.50/3
=24.50cm^3
Concentration of A mol/dm^3=Conc g/dm^3/molar mass
Molar mass of H2SO4 =2(1)+32+4(16)
=98g/dm^3
Concentration mol/dm^3=4.90/98
=0.05mol/dm^3
i)Using CaVa/CbVb=na/nb
(0.05*24.50)/Cb*25)=1/2
Cb=(0.05*24.50*2)/25
=0.098mol/dm^3
ii)Concentration of B in g/dm^3=Conc in mol/dm^3*molar mass
Molar mass of NaOH=26+16+1=40g/mol
=0.098mol/dm^3*40g/mol
=3.92g/dm^3
iii)percentage purity of B=Concentration of pure/concentration of impure *100%
=3.92/4*100%
=98%
Therefore percentage of impurity of B =100-98%
=2%
1)
volume of pipette used =25.0cm^3
indicator used =methyl orange
burette reading|rough| 21.50|0.00|21.50|
final burette readings (cm^3)|1st|21.20| 0.00. 21.20|
initial burette reading(cm^3)|2nd|31.20|10.00| 21.20|
volume of a used (cm^3)|3rd|41.20|20.00|21.20|
average volume of a used =(21.20+21.20+21.20)cm^3/3
=63.60cm^3/3
=21.20cm^3
www.naijacomms.com
H2SO4(aq) + 2NaoH(aq)+2H2O(s)
nA=1,nB=2
A=4.90gldm^3 H2SO4
molar mass H2SO4
=(1*2)+32+(16*4)
=2+32+64
=98gmol^-1
molar conc A=mass con A/molar mass A
=4.90gldm^3/98glmol
=0.05moldm^3
CAVA/CBVB=nA/nB
0.05moldm^3*21.20cm^3/CB*25.0cm^3=1/2
0.05moldm^3*21.20*2=CB*25.0
CB=0.05molldm^3*21.20*2/25.0
CB=0.0848moldm^3
in mass conc B =Molar B*MolarBmass
B=NaoH
=23+16+1
=40gmol-^3
mass conc B =0.0848moldm^3 * 40gmol
mass con B = 3.392gldm^3
% mass of impusx 100%/total mass of implusty
mass of implus =(4.0-3.392)gldm^3
=0.608gldm^3
%impurity =0.608gldm^3*100%/4.0gldm^3
=15.2%
3ai)
www.naijacomms.com
-lid
-sticky tape(to hold paper)
-choroatographic paper
-gas jar
-applied spot of solute mixture
-ion
3aii)
principle of dillution, C1 V1=C2 V2
2.0molldm^3*40
3bi)
ethanol—->ethanoic (acid)—->trioxonotrate(v) (acid)
3bii)
indicators are used to determine the end point of the reaction and to test the acidity or alkalinity of a solution
www.naijacomms.com
CHEMISTRY PRACTICAL ANSWERS...
2ai)
Observation:The salt sample dissolves completely
Inference:C is a mixture of soluble salts
2aii)
Observation:White precipitate insoluble in excess NaOH(aq)
Inference:Ca^2+ present
2aiii)
Observation:No visible reaction
Inference:Ca^2+ is present
2aiv)
Observation:Brownish fume is produced
Inference:NO2(g) form, NO3^- present
2av)
Observation:Formation of brown gas which forms a ring junction with FeSO4
Inference:NO2 form, NO3^- confirmed
2bi)
Observation:D dissolves completely. Formation of dirty green precipitate insoluble in excess NaOH(aq)
Inference:D is soluble in salt, Fe^2+ present
2bii)
Observation:Formation of a white precipitate.precipitate remains insoluble in HCl(aq)
Inference:SO3^2-,CO3^2-,SO4^2- present,SO4^2- confirmed
www.naijacomms.com
(3ai)
Drawing lebel
-lid
-sticky tape(to hold paper)
-choroatographic paper
-gas jar
-applied spot of solute mixture
-ion
3aii)
principle of dillution, C1 V1=C2 V2
2.0molldm^3*40
3bi)
ethanol---->ethanoic (acid)---->trioxonotrate(v) (acid)
3bii)
indicators are used to determine the end point of the reaction and to test the acidity or alkalinity of a solution
1)
volume of pipette used =25.0cm^3
indicator used =methyl orange
burette reading|rough| 21.50|0.00|21.50|
final burette readings (cm^3)|1st|21.20| 0.00. 21.20|
initial burette reading(cm^3)|2nd|31.20|10.00| 21.20|
volume of a used (cm^3)|3rd|41.20|20.00|21.20|
average volume of a used =(21.20+21.20+21.20)cm^3/3
=63.60cm^3/3
=21.20cm^3
equation of the reaction
H2SO4(aq) + 2NaoH(aq)+2H2O(s)
nA=1,nB=2
A=4.90gldm^3 H2SO4
molar mass H2SO4
=(1*2)+32+(16*4)
=2+32+64
=98gmol^-1
molar conc A=mass con A/molar mass A
=4.90gldm^3/98glmol
=0.05moldm^3
CAVA/CBVB=nA/nB
0.05moldm^3*21.20cm^3/CB*25.0cm^3=1/2
0.05moldm^3*21.20*2=CB*25.0
CB=0.05molldm^3*21.20*2/25.0
CB=0.0848moldm^3
in mass conc B =Molar B*MolarBmass
B=NaoH
=23+16+1
=40gmol-^3
mass conc B =0.0848moldm^3 * 40gmol
mass con B = 3.392gldm^3
% mass of impusx 100%/total mass of implusty
mass of implus =(4.0-3.392)gldm^3
=0.608gldm^3
%impurity =0.608gldm^3*100%/4.0gldm^3
=15.2%
*note your school will give a value(end point). Your value should not be more or less than +/- 0.2 to what is being given*
Keep Refreshing This Page
Loading.... Check back after 2 minutes
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Pls be patient..
Smart tags: Complete 2016 NECO expo questions and answers, free 2016 NECO expo run runz for CIVIC EDUCATION (OBJ & ESSAY PHYSICS PRACTICALLITERATURE IN ENGLISH (OBJ ) LITERATURE IN ENGLISH (PROSE ) GEOGRAPHY (OBJ & ESSAY )PHYSICS (OBJ & ESSAY) GEOGRAPHY 3 ( PRACTICAL and PHYSICAL GEOGRAPHY )CHEMISTRY PRACTICALGOVERNMENT (OBJ & ESSAY )ENGLISH LANGUAGE (ESSAY)ENGLISH LANGUAGE (OBJ) ENGLISH LANGUAGE (TEST OF ORAL )CHRISTIAN RELIGIOUS STUDIES ( OBJ & ESSAY) 9ISLAMIC STUDIES ( OBJ & ESSAY ) CHEMISTRY(OBJ & ESSAY)FINACIAL ACCOUNTING ( OBJ & ESSAY) BIOLOGY (OBJ & ESSAY )AGRIC PRACTICAL GENERAL MATHEMATICS (ESSAY) MATHEMATICS (OBJ) ECONOMIES (OBJ & ESSAY) BOOK KEEPING PAPER III&II (OBJ & ESSAY) BIOLOGY PRATICALLITERATURE IN ENGLISH (DRAMA& POETRY) OFFICE PRACTICE ( EASSY & OBJ ) AGRICULTURAL SCIENCE ( OBJ & ESSAY ) COMMERCE (OBJ & ESSAY)MARKETING FURTHER MATHEMATICS ( ESSAY ) ( OBJ )
INCOMING SEARCHES: 2016 NECO Practical Chemistry (Obj and Essay) answer, 2016 free Nabteb Practical Chemistry (Obj and Essay) answer, NECO Practical Chemistry (Obj and Essay) answer, 100% 2016 NECO Practical Chemistry (Obj and Essay) free expo/runz, 2016 NECO Practical Chemistry free answer, NECO Practical Chemistry 2016 expo, NECO Practical Chemistry 2016 expo NECO Practical Chemistry (Obj and Essay) answer, live 2016 NECO Practical Chemistry answer now available, how to get 2016 NECO Practical Chemistry (Obj and Essay) OBJECTIVES & ESSAY question and answer, 2016/2017 NECO Practical Chemistry (Obj and Essay) NECO Practical Chemistry question and answers. Download 2016 NECO Practical Chemistry (Obj and Essay) OBJECTIVES & ESSAY answer.. NECO Practical Chemistry expo, waec 2016 civic expo, Civic Education (Obj and Essay) & ESSAY runz/expo, 2016 NECO Practical Chemistry (Obj and Essay) & ESSAY expo now available, 2016 NECO Practical Chemistry (Obj and Essay) obj and theory answer Correct Real NECO Practical Chemistry (Obj and Essay) OBJECTIVES & ESSAY Prose And Objective CORRECT: 2016/2017 NECO Practical Chemistry (Obj and Essay) Prose OBJ Essay Questions And Answer Expo/Runs.
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