OBJ (Paper 1)NECO questions and answers for Chemistry 2020.
The chemistry questions and answers for NECO 2020 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).
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
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.
Therefore, 18g of liquid water will produce: (16.0 x 18) KJ of heat = -288KJmol-1
4. Define the following terms:
Heat of fusion
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.
Common Expo for Chemistry exam 2020 (Important terms)
Now that you have gotten some sample NECO chemistry theory and OBJ questions for 2020 to practice with, let me give you a quick and common expo hint for Chemistry exam 2020 (Important terms to note)
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 2020 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.