WAEC 2019 Chemistry Obj And Essay Answer – May/June Expo

WELCOME TO AYOSTUFFS WAEC 2019



invite your friends and family to ayostuffs.blogspot.com we post sure answer..


===≠=======================
KEEP REFRESHING IN EVERY 5MIN 
============================

Chemistry OBJ:
1DAABADACBD
11AABCACDADD
21CCABBDDBAA
31AABDBCDBCB
41BACBCCBDDD

(1a)
-High temperature is required 
-High pressure 
-The presence of Catalyst 

(1b)
(i) To avoid corrosion
(ii) To avoid rusting

(1ci)
Calcium oxide (CaO)  is alkaline and Hcl is acidic. The two react to form calcium chloride and water; instead of dry Hcl, after that, it will end up with wet calcium chloride.

(1cii)
Concentrated H2SO4(aq)

(1d)
Conc HNO#(aq) reacts with a solution of FeSO4(aq). The Fe2+ was oxidised to yellow Fe3+ and brown NO2(g) was given off.
ie 2HNO3(aq) + 2FeSO4(aq) + H2SO4 -> Fe2(SO4)3 + 2NO2(g) + 2H2O

(1ei)
(I) ZnO(s) + H2SO4(aq) ---> ZnSO4(aq) + H2O(l) 
(II) ZnO(s) + NaOH(aq) ---> Na2ZnO2(s) + H2O(l)

(1eii)
(III) Amphoteric property

(1f) 
(i) They have the same number of atoms 
(ii) They have different neutron number which makes their mass number to differ

(1g) 
HclO - Oxochlorate(i)acid and Hcl

(1hi) 
H2S is undergoing oxidation to S(s)

(1hii) 
SO2

(1i)
Carbon-12 scale is the standard from which atomiv masses of all nucleids are measured. It is used to ascertain mole of a substance as the amount of substance which contains as many elementry entities as there are atoms in 12 grams of carbon-12. 

(1j)
(i) The concentration of thereactants and products are equal
(ii) The rate of the forward reaction is same as rate of the backward reaction
=======≠======================
(2ai)
C10H22----->(cracking)---->C6H14 + C4H8
P is C4H8
(2aii)
H H H H
| | | |
H-C=C-C-C-H
| |
H H
H CH3 H
| | |
H-C= C- C-H
|
H
(2aiii)
P would be polymerized because it contain double bond
(2b)
Hundi's rule: Electrons occupy each orbital singly first before pairing takes place in a degenerated orbital
Aufbau's principle: Electrons enter into orbitals in order of increasing energy
(2ci)
- NaH ---> ionic
- H2 --> Covalent
- H2S --> Covalent
- NH4Cl -- Vander waals
(2cii)
- NaH ---> soluble (dissolve)
- H2 --> Insoluble
- H2S --> Moderately soluble
- NH4Cl -- soluble
(2ciii)
- H2S(g) + H2O(l) ---> H3O^+(aq) + HS(aq)
- HS(aq) + H2O(l) ---> H3O^+(aq) + S^2-(aq)
(2d)
(i)Number of unpaired electrons=zero
(ii)J would be a good reducing agent
(iii)It is found in group 2. It is a metal. Metals are good reducing agent
============================
(5ai)
DRAW THE DIAGRAM: CLICK HERE FOR THE IMAGE
(5aii)
(i)It is used in the sterilization of water for domestic and industrial use and in the treatment of sewage
(ii)It is used as a bleaching agent for cotton linen and wood-pulp
(5b)
Preparation of hydrogen from water gas:
This is called Bosch process: In this process large quantities of hydrogen are produced from cheap raw materials namely water and coke when steam is passed over red hot coke (carbon) at about 1200C, a mixture of carbon(II) oxide and hydrogen ion and water gas is produced .Excess steam is then mixed with the water gas and passed over a catalyst iron(III)oxide at 450C.As a result the carbon(II)oxide in the water gas is converted by CO2 with a further yield of hydrogen
Endothermic reaction
H2O(g) + C(s)---> CO(g)
(5ci)
The chief ore of aluminium is bauxite
(5cii)
The ore of aluminium is purified by electrolysis to remove the impurities present
(5ciii)
Carbon or platinum electrodes
(5civ)
Cryolite is added to remove the impurities present
(5d)
Coal, coal tar, ammoniacal liquor

COMPLETED

Comments

Post a Comment

Popular posts from this blog

WAEC GCE 2019 CRS/IRS Obj And Essay Answer – August/September Expo

Image
WAEC GCE CRS/IRS Obj And Essay/Theory Solution Questions and Answer –  AUGUST/SEPTEMBER 2019 Expo Runz. If you want to Get the Answers Direct To Your Phone As Sms, Kindly Send MTN Recharge Card worth of N800 Please always use MTN Number to subscribe for Direct Mobile for fast delivery of the answer Or If you want to Get the Answers Online Via Our Password/Link Kindly Send MTN Recharge Card worth of N500 How to Subscribe for the answer: Send The card pin, Subject name(CRS/IRS obj and essay/theory) and your phone number via SMS to 07060807249 Subscription Will End 1 hours Before Each Exam Starts NOTE :- Direct Mobile Candidates Gets Answers on their Phone number as SMS before Exam start. NOTE :- Please Do Not Call Our Number, Just Send Message, All SMS Sent To The Above Number Are Attended To, Our Phone Number Might Be Diverted To Avoid Distraction. Always Send Us SMS Of Your Complaint we will reply to your message immediately. WE DON’T TALK MUCH PLEASE Note -Each subject cost N800 f...
Read more

WAEC 2024 Civic Education Obj And Essay Answer – May/June Expo

Image
WELCOME TO AYOSTUFFS BEST EXAM EVER ================================== KEEP REFRESH THIS PAGE IN EVERY 5MIN ================================== CIVIC EDUCATION OBJ 1-10 ABABDBABAB 11-20 BDABDDCDCC 21-30 DABBBCBCBA 31-40 CCBABBBACC 41-50 DBBCDBDBBC COMPLETED!!! ================================== CIVIC EDUCATION SECTION A (1a)  (i) Tradition: Authority based on customs, traditions, and historical practices. (ii) Rational-Legal: Authority based on laws, rules, and regulations. (iii) Charisma: Authority based on an individual's exceptional qualities, personality, or leadership abilities. (1b) (i) Cultural Preservation: Traditional leaders play a vital role in preserving and promoting cultural heritage, traditions, and values. They help maintain cultural identity and pass it down to future generations. (ii) Conflict Resolution: Traditional leaders often serve as mediators and arbitrators, resolving conflicts within their communities. Their authority and wisdom help to settle disputes and...
Read more

WAEC 2019 mathematics Obj And Essay Answer – May/June Expo «

Image
WELCOME TO AYOSTUFFS WAEC 2019 INVITE YOUR FRIEND AND FAMILY TO AYOSTUFFS.BLOGSPOT.COM WE POST SURE ANSWER ===========≠===================== MATHS OBJ 1-10: CABDBACCBC 11-20: BCBCBBDACD 21-30:ACCBCCABBA 31-40:AADDDCBBCC 41-50: BBCDCCACCD COMPLETED ================================= MATHEMATICS THEORY ANSWER =============================== (1a)  110x = 40s Converting both sides to base 10, we have;  (1xX²)+(1xX¹)+(0×X^0) = (4×5¹) + (0×5^0) X² + X + 0 = 20 + 0 X² + X - 20 = 0 X² + 5x - 4x - 20 = 0 X(x+5)-4(x+5) = 0 (x-4)(x+5) = 0 Since X must be positive  X - 4 = 0 X = 4 (1b)  15/√75 + √108 + √432 = 15/√25×3 + √36×3 + √144×3 =15/5√3 + 6√3 + 12√3 = 3/√3 + 18√3 =3√3/3 + 18√3 = √3 + 18√3 = 19√3 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-==-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- (2a) The equation of the line through the points A(-2,7) and B(2,-3) Using the equation Y=mx+b Where m=slope of the gradient, b=the intercept at the vertical axis Hence slope=Change in Y/Chang...
Read more