WAEC Questions and Answers on Chemistry: In this article, we are happy to give you free access to WAEC chemistry questions from the past. You will know how the WAEC chemistry questions are set up, as well as a lot of other information about the test. All you have to do is pay attention and do what I tell you.
WAEC Questions and Answers in Chemistry 2023
The West African Examinations Council is in charge of running the West African Senior School Certificate Examination (WAEC), In one year, more than three million people signed up for the tests that WAEC ran.
Keep refreshing this page, as we will definitely update this page as soon as the Latest 2023 WAEC Chemistry Questions and Answers are out…
In the meantime, go through these past questions and Answers for the previous years because they are likely questions for WAEC Chemistry 2023.
WAEC Past Questions and Answers in Chemistry
You can learn more about the type of test and the questions you will be asked if you look at the questions you were asked in the past.
SECTION A
1. Make up A is made up of only carbon and hydrogen. 80% of the mass of the compound was found to be carbon.
(a) Use the information above to figure out the empirical formula for compound A.
b) It was found that compound A has a relative molecular mass of 30.
You can figure out the molecular formula of compound A by using this information.
[H = 1.00 C = 12.00] .00]
a) When calcium oxide and coke are heated in an electric furnace, carbon (ii) oxide and calcium carbide (CaC2) are made. Write the equation for this reaction.
b)When calcium carbide is mixed with water, calcium hydroxide and ethyne are made. Write the equation that shows how ethyne is made.
3. Figure out the percentage of silicon tetrachloride by mass. [2 marks] 4. The hydrides of the first two elements in Group 5 are ammonia (NH3) and phosphine (Ph3).
(a) Make a dot-and-cross diagram of the ammonia molecule. [2 marks] b) Draw a picture of the ammonia molecule and describe its shape. [3 marks]
5. The first energy that chlorine needs to become an ion is +1260KJmol-1.
(a) Explain what “first ionization energy” means.
(b) Describe the general trend in the first ionization energy values of the elements from sodium to argon in the periodic table.
6. The pH of a water-based solution is 4.0.
(a)(i) How many hydrogen ions does the solution have?
ii. What will it do to the litmus paper?
Which of the following salt solutions would make litmus react the same way? Explain why your answer is what it is. NH4Cl(aq); NaCl(aq) ; CH3OON (aq).
(b)(i) Tell the difference between a fine chemical and a heavy chemical.
(ii) Name two things that make the air dirty.
iii. Suggest one way to clean up the air in cities.
SAMPLE QUESTIONS PAPER 1 (OBJECTIVE TEST)
1. All of an element’s isotopes have the same number of
A. Nucleons, electrons, and protons.
B. There are protons and neutrons, but the number of electrons is different.
C. Neutrons have different numbers of protons and electrons.
D. Neutrons and electrons, but the number of protons is different.
2. When electrons move from one atom to another, what kind of chemical bond is formed?
A. Covalent
B. Direct
C. Ionic
D. Metallic
3. The concentration of an aqueous solution is 5 mg dm-3. How many parts per million is this? (ppm).
A. 500 ppm
B. 50 ppm
C. 10 ppm
D. 5 ppm
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4. Think about these species: H, H+, H-. How many electrons are in each of the two types of matter?
A. 1, 0, 2
B. 0, 1, 2
C. 2, 1, 0
D. 1, 2, 0
5. Two electrons with different charges can occupy the same orbital.
A. Angular momentum quantum numbers.
B. Magnetic quantum numbers.
C. Principal quantum numbers.
D. Quantum numbers with a spin.
6. How much NaOH is needed to make 250 cm3 of a solution with a concentration of 0.10mol/dm-3? [Na = 23, O = 16, H = 1]
A. 1 g
B. 4 g
C. 8 g
D. 1 6 g
7. Which of the following is not a hydrocarbon?
A. Benzene
B. Butane
C. Ethyne
Ethanamide D.
8. A substance that turns into only hydroxonium ions when it is ionized is a
Acid that is strong.
B. Strong base.
C. Not strong.
D. Weak base.
9. Small amounts of an acid or a base do not change the pH of which of the following solutions?
A. Solution for buffer
B. Neutral solution
C. Solution that is full
D. Solution that is too full
10. Protein is a long chain of molecules that are linked together.
A. amino acid molecules.
B. the molecules of fatty acids.
C. Glucose units.
D. Monosaccharides.
11. The bond that is made between H2OH2O and H+H+ to make H3O+H3O+ is
A) Present
B) Covalent
C) Electrovalent
D) Ionic
12. The minimum amount of energy that particles need to hit each other effectively is called
A) Making energy work
B) Bond energy
C) Energy in motion
D) Potential energy
13. The oxides of an element XX are X2O, XOX2O, XO, and XO2.XO2. This event shows how the law of _____ works.
A) Mass stays the same
B) Definite proportion
C) Action by many
D) Multiple proportions
14. 1.20410241.2041024 molecules would be equal to how many moles of oxygen?
NB: Avogadro’s constant (NA) =6.02×1023=6.02×1023
A) 1
B) 2
C) 3
D) 4
15. Which one of the following is true about solids?
A) Particles in a solid are not as neat as those in a liquid.
B) Liquids are less dense than solids.
C) The kinetic energies of solids are higher than those of liquids.
D) Solid things can’t be squished easily.
16. Which of the following tools can be used to accurately measure a certain amount of liquid?
A) Beaker
B) cone-shaped flask
C) Cylinder for measuring
D) Pipette
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17. The general equation for gases, PVT=KPVT=K, is a mix of
A) The laws of Boyle and Charles
B) The Boyle law and the Graham law
C) The laws made by Charles and Graham
D) The laws of Dalton and Graham
18. A flower’s scent spreading through a garden is an example of .
Brownian movement
B) Diffusion
C) Osmosis
D) Tyndal effect
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19. Propane and carbon (IV) oxide move at the same rate because [H = 1, C = 12, O = 16]. .0]
A) Both of them are gases
B) Carbon is part of their molecules
C) They both have the same amount of molecules.
D) Neither is lighter than air.
20. The energy that is added to an isolated gaseous atom when an electron is added is
A) Making atoms
B) Negative charge
C) Attraction of electrons
D) Ionization
TAKE NOTE: These aren’t real WAEC GCE chemistry questions, but they may be questions that have been asked over the years to help students understand how their tests work. Make sure to write down each question on this page.