Tuesday, 12th December, 2023
Chemistry 1 (Objective) – 11:30am – 12:30pm
Chemistry 3 (Alternative to Practical Work) – 30mins 2:00pm – 3:30pm
A. 2023 WAEC GCE CHEMISTRY ESSAY (THEORY) ANSWERS | 12TH DECEMBER, 2023
(1d)
(i) Ensure that both copper(II) oxide and dilute trioxonitrate(V) acid used in the reaction are of high purity.
(ii) Ensure that the beakers and stirring rods used are clean and dry.
OR
VERSION 2 (OTHER SOURCE)
2.
(4ai)
Air is a mixture of gases, primarily composed of nitrogen, oxygen, carbon dioxide, and trace amounts of other gases.
(4aii)
Nitrogen
(4aiii)
A noble gas is an element from Group 18 of the periodic table, characterized by its stable and inert nature.
(4aiv)
(i) They are chemically inert
(ii) They have a full outer electron shell
(iii ) They exist as colorless, odorless gases at room temperature.
(4bi)
(PICK ANY TWO)
(i) Calcium chloride
(ii) Sodium sulfate
(iii) Potassium hydroxide
(iv) Anhydrous calcium sulfate
(4bii)
N2 + 3H2 ----> 2NH3
(4biii)
It is often done through upward displacement of air or downward delivery into a container.
(4biv)
Differences
in the method of collection of gases depend on factors such as the
gas's density, solubility, and reactivity with atmospheric components.
(4ei)
-Haematite undergoes reduction
-Coke acts as a reducing agent and provides heat.
-Limestone undergoes decomposition to form calcium oxide.
(4eii)
Cast
iron is brittle and contains a higher percentage of carbon compared to
wrought iron, which is malleable and has a lower carbon content.
(4eiii)
Conditions
favoring the conversion of sulfur (IV) oxide to sulfur (VI) oxide
include low temperature, high pressure, and the presence of a catalyst.
(4di)
Both
diamond and graphite have high melting points due to the strong
covalent bonds between carbon atoms in their structures. In diamond,
each carbon atom forms four strong covalent bonds in a tetrahedral
structure, while in graphite, carbon atoms are arranged in layers held
together by weak van der Waals forces.
(4dii)
(I) Copper would react with silver trioxonitrate (V) but not with zinc trioxonitrate (V).
(II) The solution would change color, and silver metal would be observed as a solid precipitate.
Soap is manufactured through a process called saponification. In this process, pellets of sodium hydroxide (NaOH) and vegetable oil are used as the main ingredients. First, the vegetable oil is heated, and then the heated vegetable oil is mixed with sodium hydroxide pellets. This mixture is stirred continuously until a thick, creamy consistency is achieved. This mixture is then left to cool and solidify into soap bars. The sodium hydroxide reacts with the fatty acids present in the vegetable oil, resulting in the formation of soap molecules.
(5bi)
The industrial preparation of oxygen from air involves a process called fractional distillation. Air is first compressed and cooled, causing it to liquefy. This liquefied air is then subjected to fractional distillation, a process that separates the different components of air based on their boiling points. Oxygen, which has a lower boiling point than nitrogen, is separated and collected as a pure gas.
(5bii)
(i) oxygen: Oxygen supports combustion and is necessary for a flame to burn.
(ii) Hydrogen: hydrogen is highly flammable and can readily ignite.
(5ci)
(i) Calcium hydroxide: It helps to neutralize any acidic components and improve the overall quality of the water.
(ii) Calcium: is an essential nutrient for human health and is important for the development and maintenance of strong bones and teeth.
(5cii)
(i) Natural sources
(ii) Fossil fuel extraction and combustion
(5ciii)
When sulfur reacts with iron, iron sulfide (FeS) is formed. This reaction can be represented by the equation:
Fe + S -> FeS
(5di)
The term hardness of water refers to the concentrationof dissolved minerals, particularly calcium and magnesium ions. Hard water can cause build-up and scaling in pipes and appliances, reduce the effectiveness of soaps and detergents, and can also affect the taste and odor of water.
(5dii)
2H2SO4 + 2NaCl –>> 2HCl + Na2SO4
(5diii)
Fe2O3 + 3CO –>> 2Fe + 3CO2
B. 2023 WAEC GCE CHEMISTRY OBJECTIVES (OBJ) ANSWERS | 12TH DECEMBER, 2023
1-10: ACBBABACBA11-20: ABBBADBBAB
21-30: CACBDCABCC
31-40: BDBDBBBADA
41-50: DAADBDBADD
C. 2023 WAEC GCE CHEMISTRY PRACTICAL ANSWERS | 12TH DECEMBER, 2023
Answers Loading...................................................
- JUST GO OUT AND BUY MTN CARDS OF N600 (500 + 100 = 600)
- GO TO YOUR MESSAGE, TYPE THE MTN CARD PINS CORRECTLY AND SEND TO 08107431933.
- DON'T CALL THE NUMBER, JUST TEXT, IF THE CARDS PINS ARE VALID, A REPLY WILL BE SENT TO YOU CONFIRMING THAT YOU HAVE BEEN SUBSCRIBED.
- DO
NOT TRY TO LOAD THE CARD AFTER SENDING AND NO REPLY WAS SENT
IMMEDIATELY, BE PATIENT AS WE ATTEND TO MESSAGES IN ASCENDING ORDER
- RELAX AND WAIT FOR YOUR ANSWERS 45 MINUTES AFTER EXAM STARTS.
- NB: DO NOT SEND USED CARD PINS OR YOUR NUMBER WILL BE BLOCKED IMMEDIATELY.
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2 Comments
Thank you sir!!
ReplyDeleteWeldone for supplying answers for students. They dont need to read again because of your heroics. Is that how they will become reat leaders. Gid is watching
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