Keep Subscribing With Us @ Waecupperoom.blogspot.com To
Enjoy Our Service And Get Your Verified
Solution Before the Exam Time.
====================================
NECO-CHEMISTRY- OBJECTIVE AND THEORY -2021-ANSWERS
CHEMISTRY OBJ & ESSAY
10:00AM - 01:00PM
Keep Subscribing With Us @ waecupproom To
Enjoy Our Service And Get Your Verified
Solution Before the Exam Time.
=========================================
NECO-CHEMISTRY-OBJECTIVE-2021-ANSWERS
=========================================
[OBJECTIVES]
01-10: EECBBAEBBB
11-20: DDDBEAEABB
21-30: DBECCDAAAB
31-40: BADCBACDAC
41-50: CECCEADBDC
51-60: CEBEEDDBAE
Completed.........
CHECK BACK BY 04:00AM
=========================================
DON'T SHARE OUT YOUR PIN TO AVOID CASTING
=========================================
=========================================
NECO-CHEMISTRY-ESSAY-2021-ANSWERS
=========================================
[ESSAY]
(1ai)
(i) Base has bitter taste
(ii) Base is soapy to touch
(iii) Base turns red litmus paper blue
(1aii)
(i)Shift conversion
(ii)Removal of carbon (iv) oxide
(iii)Steam reforming
(1aiii)
Cracking is the breaking down or decomposition of a compound by action of heat. It also involves splitting larger molecules into smaller molecules by subjecting them to high temperature and pressures.
(1aiv)
Thermal cracking
(1bi)
P ion = 1s²2s²2p⁶
(1bii)
Formula of chloride is Pcl2
(1biii)
Reducing agent
This is because it undergoes oxidation by losing electrons
(1ci)
Electron affinity is the energy released when a gaseous atom gains an electron to form a gaseous negative ion.
(1cii)
This is because it has lone pairs of electrons
(1di)
(i) By adding a catalyst
(ii) FeS(s) + 2HCl(g) -----> FeCl(g) + H2S(s)
Xg = ?
No. of FeCl2 = 127g/mole
No. of FeS= 88g/mole
Mole = Mass/ No. of Mass = 3.2/127 = 0.025mole of FeCl2
By comparison,
1 mole of FeS = 1 mole of FeCl2
X moles of FeS = 0.025 of FeCl2
X = 0.025mole of FeS
Recall,
Mass = Mole * molar mass
Mass = 0.025*88
Mass = 2.2g of FeS
X = 2.2g
(1dii)
(i)Chlorofluorocarbons
(ii)Ammonia
=====================================
(2ai)
(i) Gas molecules are in constant, rapid, straight motion and collide with one another and with the walls of the container.
(ii) The Force of attraction (cohesive forces) between the gas molecules are negligible.
(iii) Gases consist of molecules widely separated in space. The total volume of the gas molecules is negligible in comparison with the volume of the container.
(2aii)
(i) They both react with akali to give a normal salt.
(ii) They both react with carbon. Carbon reduce carbon(iv)oxide to carbon(ii)oxide and sulphur (iv) oxide to sulphur.
(2aiii)
Copper ----> Iron ----> Aluminum ----> Magnesium.
(2aiv)
Aluminum (Al)
(2bi)
Activation Energy is the minimum amount of energy possess by colliding reactant particles for a chemical reaction to occur.
(2bii)
It lowers the activation energy so that more reactant particles are able to react when they collide.
(2biii)
Nickel (Ni).
(2ci)
(i) Ester Formation: Ethanoic acid reacts reversibly with alkanols to form esters.
(ii)
(2cii)
(i) Cl2(g) + 2KI ----> 2KCl2 + I2
(ii) Zn(s) + Cl(g) ----> ZnCl(s)
(2ciii)
Cl2 + 2NaOH ----> NaCl(aq) + H2O + NaClO(aq)
(2civ)
Covalent Bond.
(2d)
(i) Butane
(ii) Propene
(iii) Ethanol
(iv) Ethyne
=====================================
(4a)
(i) This is the heat evolved when one molecule of the substance is burned completely in oxygen under standard conditions.
(ii) Isomerism is the occurrence of two or more compounds with the same molecular formula but different structures.
(4bi)
Acidic - NO2
Basic - FE2O3
Neutral - CO
Amphoteric -AL2O3
(4bii)
(i) Nitrous oxide
(ii) Carbon (iv) oxide
(4ci)
Fractional distillation of liquid air
(4cii)
2KNO3 —> 2KNO2(s) + O2(g)
(NH4)2 (CO)3 —> 2NH3(g) + CO2(g) + H2O(g)
(4ciii)
No of molecules=4/16 × 6.02 × 10²³
=1.51 × 10²³
(4di)
(i) Sodium.
(ii) Magnesium.
(4dii)
(i) W= CO2 Carbon (iv) oxide
(ii) Carbon Or Coke
(4diii)
(i) Rusting
(ii) Oxidation
=====================================
(5ai)
Gay-Lussac's law states that when gases react, they do so in volumes which are simple ratios to one another and to the volumes of the products, if gaseous, provide that the temperature and pressure remain constant.
(5aii)
2CO + O2 ----> 2CO2
2 1 2
100cm³ 70cm³ 100cm³
Total volume = 100+70+100 = 270cm³
(5bi)
(i)It is used in the production of other chemical substances
(ii)It is used as a drying or dehydrating agent
(5bii)
(i) ZnCO3 -----> ZnO + CO2
->Conditions<-
- High temperature
- High pressure
(ii) ZnO + H2SO4 ----> ZnSO4 + H2
->Conditions<-
- Catalyst
- Surface area
(5biii)
(i) Crystallization method
(ii) By heating the ZnSO4 with an alkali metal carbonate
(5c)
(i) This is due to the presence of extra electrons not used for bonding graphite
(ii) This is because sodium salts are soluble and double decomposition is used for the production of insoluble salts
(iii) It is an alkali substance i.e possesses basic properties
(5di)
(i)Bitumen coal.
(ii)Peat coal.
(5dii)
Fractional distillation.
=========================================
Solutions in Pictures ⬇️⬇️⬇️⬇️⬇️⬇️🔻🔻🔻🔻
.....
Keep Subscribing With Us @ Waecupperoom.blogspot.com To
Enjoy Our Service And Get Your Verified
Solution Before the Exam Time.
=======================================
Waec Upper room Solution
Love you All
Keep Inviting your Friends And Classmates to Waecupperoom 100% Legit.
Tell the world about Waecupperoom.blogspot.com
=================================================================
COMPLETED.....===========================================
CLICK HERE TO CHAT US
Www.waecupoerroom.blogspot.com
We Remain The No1 Best Exam Portal
=====================================
3 Comments