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That is the reason we are sharing this NECO chemistry expo 2021 with candidates so that they will not be stranded during the exam.
Proper usage of this material will guarantee you sure insights on the kind of NECO questions for chemistry 2021 that you should expect and how to draft expo answers for them.
OBJ (Paper 1)NECO Questions and Answers for Chemistry 2021.
The chemistry questions and answers for NECO 2021 will be in two papers. The first paper (paper 1) is the OBJ (objective) and the second paper is paper 2 (theory, essay, calculations and show working).
So in this aspect, I will supply you with the basic NECO chemistry questions 2021 samples with correct NECO chemistry answers 2021 to the NECO 2021 chemistry questions and answers samples.
Check out the sample solved Questions and Answers below.
Sample OBJ Chemistry Questions and Answers for NECO 2021
1. Who found the Periodic table?
- Period Dickson
- John Dalton
The correct answer is D. Mendeleev
2. Periodic table is arranged in ____and _____
- Lanthanide and Actinide
- Groups and periods
- Groups and electronic configuration
- Atomic number and outer shell
- Transition and atomic shell
The correct answer is B. Groups and periods
3. Which of this is not a constituent of Urine.
The answer is E. Bacteria
4. Bronze is made up of _____ and _____?
- Iron and copper
- Tin and iron
- Copper and tin
- Nickel and iron
- Zinc and copper
The answer is copper and tin
5. Which of the following is not a metalloids
The correct answer is D. Nickel
6. The most reactive non-metal is_____?
The correct answer is A. Fluorine
7. What is the I.U.P.A.C name of CH3CH2OH?
The correct answer is D. Ethanol
8. Which of this is not an aromatic compound
The correct answer is E. Tulane
9. The chemical symbol for Silver is____?
The answer is B. Ag
10. An element with an atomic number of 16 will likely belong to group_____ on the periodic table.
The answer is E.6
11. Group 7 elements are also known as _______?
- Alkali metals
- Transition elements.
- Alkali earth metals.
The correct answer is A. Halogens
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Theory Paper 2, Chemistry Questions and answers 2021 Samples
Practice these questions because they might come up in the exam.
1. a. State Faraday’s first law of electrolysis.
Faraday’s first law of electrolysis states that the mass (m) of a substance liberated at an electrode during electrolysis is directly proportional to the quantity of electricity (Q) passing through the electrolyte.
M > Q
Where quantity of electricity = current (I) x time (t).
i.e Q = It.
ii. Explain an electrolytic cell.
An electrolytic cell consists of a container of electrolyte with two electrodes connected to a suitable direct current supply.
2a. List 4 constituents of Air.
- Carbon (iv) oxide
- Rare gases.
2b. Write the IUPAC name of CH2OH CHOHCHO: Ans. 2, 3-Dihydroxy propanal.
3. When 4.5g of liquid water was formed by burning hydrogen gas in oxygen, -72KJ of heat was given off. Calculate the standard heat of formation of water.
Equation of reaction.
H2(g) + 1/2O2(g) → H2O(l) ∆H©f = ? KJmol-1.
4.5g of liquid water produces -72KJ of heat
1.0g of liquid water produces – 72
= -16.0KJ of heat
Therefore, 18g of liquid water will produce: (16.0 x 18) KJ of heat = -288KJmol-1
4. Define the following terms:
- Bomb calorimeter
- Heat of fusion
- Spontaneous reaction
- Gibbs free energy.
Bomb calorimeter: A bomb calorimeter consists of a strong cylindrical steel vessel lined with enamel to prevent corrosion.
The heat of fusion: This is the heat change when one mole of solid is melted.
Entropy: Entropy is a degree of disorderliness or randomness of a system.
Spontaneous reaction: A spontaneous reaction is a reaction that occurs on its own without the assistance of an external agent.
Gibbs free energy: The free energy (G), of a chemical system is the energy that is available for doing work.
NECO Expo for Chemistry exam 2021 (Important terms)
IUPAC: IUPAC means, International Union of Pure and Applied Chemistry.
Nucleus: The Nucleus is made up of Proton and neutron.
Laws of Chemical combination includes;
- Law of conservation of mass
- The law of definite proportions or constant composition.
- Law of multiple proportions.
Chemical symbol: A chemical symbol of an element represents an atom of the element.
Radicals: Radicals are groups of an atom carrying charges that keep their identity and react as a single unit.
Empirical formula: Empirical formula is the simplest possible formula giving the ratio of atoms in a molecule of the compound.
Mole: A mole is the amount of substance that contains as many elementary entities as that in a 12g of carbon.
Isotope: An isotope occurs in elements with the same atomic number (Number of protons) but different mass numbers (because of varying numbers of neutrons).
- The Avogadro’s Number (NA) is 6.02×1023
PH scale: the PH scale is numbered from 0 – 14. From 0 to 6 indicates the degree of acidity, 7 is neutral while, above 7 to 14 indicates the degree of alkalinity.
I am sure this NECO Chemistry Questions and answers 2021 material will help you to perform better in this exam.
Please, treat the above questions as sample questions and not as the main exam questions.