WAEC Chemistry Questions and Answers 2023: OBJ/Essay
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The West African Examination Council (WAEC) conducts the West African Senior School Certificate Examination (WASSCE) for Chemistry. This examination tests students’ knowledge and skills in the subject, preparing them for higher education and career opportunities. In this comprehensive guide, we provide you with essential information, sample questions, and answers to help you excel in the Objectives and Essay sections of the WAEC Chemistry exam in 2023.
Overview of WAEC Chemistry Examination
The WAEC Chemistry examination consists of two main sections: Objectives and Essay. The Objectives section contains multiple-choice questions that test students’ basic understanding of Chemistry concepts. On the other hand, the Essay section requires students to provide detailed explanations and solutions to various Chemistry problems.
To excel in the WAEC Chemistry examination, you need to have a solid understanding of the subject matter. This guide will provide you with valuable insights and sample questions, covering both the Objectives and Essay sections of the exam.
WAEC Chemistry Objectives
The Objectives section consists of multiple-choice questions, which test your basic understanding of Chemistry concepts. In this section, we provide you with some sample questions and answers to help you prepare for the 2023 WAEC Chemistry Objectives.
Sample Objective Questions
- Which of the following elements will burn in excess oxygen to form a product that is neutral to litmus?
A. Carbon B. Hydrogen C. Sulphur D. Sodium
Answer: B. Hydrogen
- A solution of salt formed from HCl and NH3 solutions is:
A. Acidic B. Basic C. Complex D. Neutral
Answer: D. Neutral
- The boiling points of water, ethanol, methylbenzene, and butan-2-ol are 373.0K, 351.3K, 383.6K, and 372.5K respectively. Which liquid has the highest vapor pressure at 323.0K?
A. Water B. Methylbenzene C. Ethanol D. Butan-2-ol
Answer: C. Ethanol
WAEC Chemistry Essay
The Essay section requires students to provide detailed explanations and solutions to various Chemistry problems. In this section, we provide you with a comprehensive list of sample essay questions and answers to help you prepare for the 2023 WAEC Chemistry Essay.
Sample Essay Questions and Answers
- (a) Define the following terms:
(i) Atomicity (ii) Isotopes
(b) Elements P, Q, and R have atomic numbers 9, 16, and 20, respectively. Which of these elements would gain electron(s) during ionic bonding?
(c) Write the electron configuration of the following elements:
(i) 9F (ii) 20Ca
(a) (i) Atomicity refers to the number of atoms present in a molecule of an element or compound. For example, the atomicity of oxygen (O2) is 2, and that of ozone (O3) is 3.
(ii) Isotopes are varieties of an element that have the same atomic number but different mass numbers due to the different number of neutrons in their nuclei. For example, the isotopes of hydrogen are protium (1H), deuterium (2H), and tritium (3H).
(b) Elements with atomic numbers 9 (P) and 16 (Q) would gain electron(s) during ionic bonding because they have fewer than four electrons in their outermost shells.
(c) Electron configuration of:
(i) 9F: 1s² 2s² 2p⁵ (ii) 20Ca: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²
- (a) Define the following terms:
(i) Standard electrode potential (ii) Redox reaction
(b) Balance the following redox equation: MnO₄⁻ + I⁻ + H⁺ → Mn²⁺ + I₂ + H₂O
(a) (i) Standard electrode potential is the potential difference (voltage) between an electrode and its respective half-cell when all the species involved are in their standard states (298 K temperature, 1 atm pressure, and 1 mol/dm³ concentration).
(ii) A redox reaction is a chemical reaction in which the oxidation states of the atoms involved in the reaction change. One species is reduced (gains electrons), and another is oxidized (loses electrons).
(b) The balanced redox equation is: 2MnO₄⁻ + 10I⁻ + 16H⁺ → 2Mn²⁺ + 5I₂ + 8H₂O
Tips for Success in WAEC Chemistry Examination
- Understand the concepts: Develop a strong foundation in Chemistry by thoroughly understanding the basic concepts, principles, and theories.
- Practice regularly: Solve numerous practice questions and problems to improve your problem-solving skills and enhance your understanding of the subject.
- Manage your time effectively: Allocate adequate time for each section of the exam, ensuring you have enough time to read and understand the questions and provide well-thought-out answers.
- Learn from your mistakes: Review your practice questions and identify areas where you may be struggling, then focus on improving in these areas.
- Stay updated: Keep abreast of the latest developments in Chemistry and apply your knowledge to real-life situations.
In conclusion, preparing for the Objectives and Essay sections of the WAEC Chemistry examination requires dedication, persistence, and a strong understanding of the subject matter. By following the tips provided in this guide and practicing with the sample questions and answers, you will be well on your way to achieving success in the 2023 WAEC Chemistry examination.