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*2020 WAEC CHEMISTRY ANSWER*
1ai) Faraday's First Law of Electrolysis states that the chemical deposition due to the flow of current through an electrolyte is directly proportional to the quantity of electricity (coulombs) passed through it.
1aii) Strong electrolytes ionize completely (100%), while weak electrolytes ionize only partially
1b) Properties of Ethyne (choose one)
Ethyne is a colorless gas with a sweet smell when pure.
It is slightly less dense than air
It is almost insoluble in water.
It burns with a sooty flame due to high proportion of unburnt carbon.
1c) Unsaturated hydrocarbons are hydrocarbons that have double or triple covalent bonds between adjacent carbon atoms. ..
CH3COOH + CH3OH-->CH3COOCH3 + H2O
By removing the main product continuously.
Mzn = 3.75g
Mzn = 65.0g/mol
nH² =0.0577mole because the mole ratio is the same
Zinc (from + 2 to + 4)
(i)Each spectral line is caused by one electron
(ii)Electron can exist only in circular orbit of definite quantum energy.
It could not account for the spectrum at note complicated atoms
(i)Temperature of the reacting system
(ii)Pressure of the reacting system
(iii)Concentration of the reacting system
Both liberate carbon(iv) oxide
One produce a chloride salt , the other produce an ethronate salt
*Evaporation* is a normal process that occurs when the liquid form changes Into the gaseous form; while causing an increase in the pressure or temperature. *Boiling* is an unnatural process where the liquid gets heated up and vaporized due to continuous heating of the liquid
A = trans 1,2 dichloroethane
B=Cis 1,2 dichloroethane
Because they are isomers. Isomers have same chemical properties but different physical properties.
(i) Destroying gaseous emissions.
(ii) Boiling is the rapid vaporization of a liquid
WHEN NACL IS ADDED: The more salt (or any solute) added to water, the more you raise the boiling point. Reduction of atmospheric pressure lowering the atmospheric pressure will lower the boiling point of the liquid.
A saturated solution contains the maximum amount of solute that will dissolve at that temperature. Any further addition of solute will result in undissolved solid on the bottom of the container. An unsaturated solution contains less than the maximum amount of solute that can be dissolved at that temperature.
Add solute to a liquid until no more will dissolve. Solubility often increases with temperature, so you may be able to get more solute into a hot solvent than you would if Increase in pressure
Temperature and Pressure
(★) Temperature affects the solubility of both solids and gases,
(★) Pressure only affects the solubility of gases
Isotopy is simply a phenomenon whereby elements exist in various forms that have the exact same chemical properties but different atomic mass.
-Negatively charged electrons,
-Positively charged protons and
-Neutrons which have a neutral charge
sulfur dioxide (Choose any 2)
5aii) The aim of the fountain experiment is to prove that HCI is highly soluble in water.
5aiii) The experiment consists of introducing water through an inlet to a container filled with ammonia gas.... Ammonia dissolves into the water and the pressure in the container drops. As a result, more water is forced into the container from another inlet creating a fountain effect
5b) Fumman Chemicals
-Cormart Nigeria Limited
5bii) The magnitude of the emitted to the air dusts and gases, liquid and solid wastes disposal produced by chemical industry is presented
-.. Some hazardous agents, occurring in the work environment, morbidity and sickness absenteeism rates, noted among employees in chemical industry, are considered.
coal tar ammonia liquor
5cii) COKE=>It is used to reduce iron oxide to produce iron.
Coal gas=>is used in lighting
Coal tar=>It may be applied to the affected area to treat psoriasis and seborrheic dermatitis (dandruff).
- precipitation methods
Calcium ions in the water are good for children's teeth and bones.
-Limescale (a hard crust) forms inside kettles.
-This wastes energy whenever you boil a kettle. It helps to reduce heart disease.
*CRS QUESTIONS ANSWERS*
1a) Genesis 1 vs 2.
2Now the earth was  formless and empty, darkness was over the surface of the deep, and the Spirit of God was hovering over the waters.
3And God said, "Let there be light," and there was light.
4God saw that the light was good, and he separated the light from the darkness.
5God called the light "day," and the darkness he called "night." And there was evening, and there was morning--the first day.
6And God said, "Let there be an expanse between the waters to separate water from water."
7So God made the expanse and separated the water under the expanse from the water above it. And it was so.8God called the expanse "sky." And there was evening, and there was morning--the second day.
9And God said, "Let the water under the sky be gathered to one place, and let dry ground appear." And it was so.
10God called the dry ground "land," and the gathered waters he called "seas." And God saw that it was good.
11Then God said, "Let the land produce vegetation: seed-bearing plants and trees on the land that bear fruit with seed in it, according to their various kinds." And it was so.
12The land produced vegetation: plants bearing seed according to their kinds and trees bearing fruit with seed in it according to their kinds. And God saw that it was good.
13And there was evening, and there was morning--the third day.
14And God said, "Let there be lights in the expanse of the sky to separate the day from the night, and let them serve as signs to mark seasons and days and years,
15and let them be lights in the expanse of the sky to give light on the earth." And it was so.
16God made two great lights--the greater light to govern the day and the lesser light to govern the night. He also made the stars.
17God set them in the expanse of the sky to give light on the earth,
18to govern the day and the night, and to separate light from darkness. And God saw that it was good.
19And there was evening, and there was morning--the fourth day
.20And God said, "Let the water teem with living creatures, and let birds fly above the earth across the expanse of the sky."
21So God created the great creatures of the sea and every living and moving thing with which the water teems, according to their kinds, and every winged bird according to its kind. And God saw that it was good.
22God blessed them and said, "Be fruitful and increase in number and fill the water in the seas, and let the birds increase on the earth."
23And there was evening, and there was morning--the fifth day.
24And God said, "Let the land produce living creatures according to their kinds: livestock, creatures that move along the ground, and wild animals, each according to its kind." And it was so.
25God made the wild animals according to their kinds, the livestock according to their kinds, and all the creatures that move along the ground according to their kinds. And God saw that it was good.
26Then God said, "Let us make man in our image, in our likeness, and let them rule over the fish of the sea and the birds of the air, over the livestock, over all the earth,  and over all the creatures that move along the ground."
27So God created man in his own image, in the image of God he created him; male and female he created them.
28God blessed them and said to them, "Be fruitful and increase in number; fill the earth and subdue it. Rule over the fish of the sea and the birds of the air and over every living creature that moves on the ground."
29Then God said, "I give you every seed-bearing plant on the face of the whole earth and every tree that has fruit with seed in it. They will be yours for food.
30And to all the beasts of the earth and all the birds of the air and all the creatures that move on the ground--everything that has the breath of life in it--I give every green plant for food." And it was so.
31God saw all that he had made, and it was very good. And there was evening, and there was morning--the sixth day
The prayer of the righteous is very powerful in its working (or, operation).” James has just exhorted us to “pray for one another, so that you may be healed.” This may refer to healing from illness, especially illness that may be the result of unconfessed sin. Or, it may refer also to spiritual healing, since James has instructed us to confess our sins to one another. But his point is that whether your need is physical or spiritual, prayer is very powerful. But, he qualifies it. In other words if we have been justified by faith, we stand before God with a righteousness that is not our own. If you think that you can approach God through your righteousness, you do not understand the gospel. The gospel shuts us all up under sin, showing that our own righteousness will never satisfy God’s holy.
(Pick any 4)
(i) Deterioration of the environment through depletion of resources such as air, water and soil
(ii) Habitat destruction
(iii) the destruction of the of ecosystem
(iv) extinction of wildlife
After the prayer of Moses to God to appoint a leader to replace him so that a lsrael would not be without a leader. God instructed him to Joshua the son of Nun,a man with the spirit of God and lay his hand upon him. He told Moses to make him stand before Eleazer, the priest and the entire congregation. He should be commissioned before the people and this would make the people to obey himas soon as he becomes a leader.
Prior to the above, Joshua was one of the twelve spies sent out and his courage gave a lot of support to the people . Also, he was a man of faith and through his faith the people actually overcome at the end.
The instructions God gave to Joshua on his assumption of leadership over Israel.
1. God assured Joshua of his victory and success in leadership assignments.
2. The book of the law should not depart from the mouth of Joshua.
3. Joshua should meditate on the book of the law day and night in other to do what is written on it.
4. By doing what is written on the book of the law,he would make his way prosperous Continuation
and success would come to his way.
5. God directed Joshua on how to conquer the city of Jericho and the people were to match against it for seven days.
(i)political leaders are expected to be courageous
(ii)Political leaders are expected to lead the people by the law of God
(iii)Political leaders are expected to be good examples before the people that they are leading.
(Pick any 4)
(a) Increases decision making capacity.
(b) Increases chances of success.
(c) Self-control can help us curtail impulsive behaviors such as lying and binge drinking.
(d) Improves FOCUS.
(e) Promotes Congruence
(4a) solomons prayer at the time of dedication of the jewish temple is.... "Hear our prayer of dedication on this historic day we gathered together in a solemn assembly"
Solomon worshipped and praised the Lord.
He asked for the forgiveness of his sins and those of his subjects.
He prayed for their neighbours, for strangers and even for their enemies.
He also prayed against war, famine, sin, drought and captivity.
And that any time they sin and repent God should forgive and answer them.
(ii)It’s built into our very existence. Because we are created in His image, God’ image, we are to mimic Christ-like behavior.
(ii)Prayer is an avenue to resolution, the path to finding an answer to a problem. It provides insight to our dilemmas and tough decisions.