Explore the ultimate guide on WAEC Chemistry free Questions and Answers here to help you succeed. People may wish to have access to WAEC expo/runs in Chemistry, but I tell you, the details on Objectives and theory Chemistry WAEC Questions and Answers provided for you here is going to guarantee your success.
The West African Examination Council (WAEC) Chemistry paper 1 and 11 (Objectives and Essay) schedule is available in the official WAEC Timetable. All the necessary materials will be provided by the management board for the smooth running of the exams. To pass WAEC Chemistry with A1, keep reading fore latest news on correct WAEC Chemistry answers.
WASSCE Chemistry past Questions papers has been provided here to help you get ready for the questions that will be presented to you. Likely WAEC Chemistry expo questions and Answers and how to answer the questions without wasting time are equally provided.
Chemistry Answers to Objectives Questions
There are free WAEC Chemistry Past Questions and Answers for you. Take your time and make good use of it while waiting for the latest update on Likely WAEC Chemistry expo.
The following are Sample WAEC Chemistry Objectives Past Questions and Answers:
1. How many grammes of NaOH(s) would be needed to produce 100.0 cm3 of a 0.20 mol dm-3 NaOH, (aq)? [NaOH = 40.0]
- A. 800.0g
- B. 0.02 g
- C. 20.0 g
- D. 0.80 g
Answer: D (0.80 g)
2.How many moles of copper would be deposited by passing 1 Faraday of electricity through a CuCl2
solution?
- A. 2 moles
- B. 0.5moles
- C. 0.025moles
- D. 1 mole
Answer: B ( 0.5moles)
3. Which of the following gases has the lowest rate of diffusion?
[H=1.0, C=12.0, N = 14.0, O= 16.0]
- A. Nitrogen
- B. methane
- C. Ammonia
- D. Oxygen
Answer: D (Oxygen)
4. The best indicator to use for the titration of ethanoic acid with sodium hydroxide is
- A. methyl orange
- B. phenolphthalein
- C. screened methyl orange
- D. methyl red
Answer: B (phenolphthalein)
5. Thermal cracking of alkanes usually
- A. requires hydrogen
- B. produces only small alkanes
- C. involves decomposition
- D. is an exothermic process
Answer: C (involves decomposition)
6. Petrochemistry is an example of
- A. applied chemistry
- B. Biochemistry
- C. Pure chemistry
- D. Environmental chemistry
Answer: A (applied chemistry)
7, Which of the following elements has its valence electrons in the s-orbital?
- A. Carbon
- B. Phosphorus
- C. Sodium
- D. Aluminum
Answer: C (Sodium)
8, Positive ions in a sea of electrons are found in
- A. dative bonds
- B. metallic bonds
- C. covalent bonds
- D. ionic bonds
Answer: B (metallic bonds)
9. The gas that is less dense than air is
- A. nitrogen
- B. Oxygen
- C. Carbon(IV) oxide
- D. chlorine
Answer: A (nitrogen)
10, One of the laws or theory below cannot be explained by the application of the kinetic theory of gases?
- A. Dalton’s atomic theory
- B. Gay- Lussac’s law
- C. Boyle’s law
- D. Charle’s law
Answer: A (Dalton’s atomic theory)
11.Consider the reaction represented by the following equation:
x Al + yCl2 → z AlCl3
- A. 2, 3 and 2
- B. 2, 2 and 3
- C. 1, 2 and 1
- D. 1, 1 and 1
Answer: A ( 2, 3 and 2)
12.Water pipes are produced from
- A. polyethene
- B. Perspex
- C. polystyrene
- D. poly vinyl chloride
Answer: D ( poly vinyl chloride)
13. The oxidation number of iron, in its free state is
- A. 0
- B. +1
- C. +2
- D. +3
Answer: A (0)
14.How many isomers can be formed from a compound with molecular formula C5H12 ?
- A. One
- B. Two
- C. Three
- D. Four
Answer: C (Three)
15.Tetraoxosulphate (VI) acid is considered as a heavy chemical because
- A. its relative molecular mass is high
- B. a high tonnage is produced every year
- C. it is an inorganic chemical
- D. it is used to manufacture heavy chemicals
Answer: B (a high tonnage is produced every year)
16. Which of the following compounds is formed by the oxidation of ethanol?
- A. C2H4CO2H
- B. C2H5OH
- C. CH3OH
- D. CH3CO2H
Answer: D (CH3CO2H)
17.Which of the following is a monomer of polythene?
- A. Ethanol
- B. Vinyl chloride
- C. Ethene
- D. Ethane
Answer: C (Ethene)
18.The main function of limestone in the blast furnace during the extraction of iron is to
- A. act as catalyst
- B. remove impurities
- C. act as a reducing agent
- D. supply Carbon(IV) oxide
Answer: B (remove impurities)
19.An atom of an element in the ground state contains 8 valence electrons. The element is considered as a
- A. metal
- B. semi-metal
- C. noble gas
- D. halogen
Answer: C ( noble gas)
20.When an element exists in two or more forms in the same physical state, it exhibits
- A. isotopy
- B. allotropy
- C. isobars
- D. isomerism
Answer: B (allotropy)
21.How many covalent bonds are formed by Nitrogen?
- A. 1
- B. 2
- C. 3
- D. 4
Answer: C (3)
22.The metallic bonding in aluminium is strong because of large number of
- A. delocalized electrons
- B. immobile electrons
- C. lone pair electrons
- D. valence electrons
Answer: A (delocalized electrons)
23.The hardest form of carbon is
- A. charcoal
- B. coke
- C. diamond
- D. graphite
Answer: C (diamond)
24.When s and p block elements react, the bond formed is
- A. electrovalent
- B. covalent
- C. metallic
- D. dative-covalent
Answer: A (electrovalent)
25.The electron configuration of 29 Cu is
- A. 1S2 2S2 2P6 3S2 3P6 4S1 3d10
- B. 1S2 2S2 2P6 3S2 3P6 4S3 3d9
- C. 1S2 2S2 2P5 3S2 3P6 4S2 3d10
- D. 1S2 2S2 2P6 3S2 3P2 4S1 3d10
Answer: A (1S2 2S2 2P6 3S2 3P6 4S1 3d10)
26. Pure water contaminated with quicklime will have a pH of
- A. 1
- B. 6
- C. 7
- D. 8
Answer: D (8)
27.Pairs of outermost shell electrons which are not used in bonding are
- A. lone pairs
- B. bonding pairs
- C. valence electrons
- D. electrovalent electrons
Answer: A (lone pairs)
28.The volume of 22g of CO2 at stp is equivalent to [C =12, O =16, molar volume at stp = 22.4 dm3 ]
- A. 22.0 dm3
- B. 22.4 dm3
- C. 11.2 dm3
- D. 5.6 dm3
Answer: C (11.2 dm3)
29.Which of the following conditions are necessary for the preparation of alkanoates from alkanols and alkanoic acid?
- A. Water and NaOH
- B. Conc. H2SO4 and heat
- C. NaOH and heat
- D. water and aqueous HCl
Answer: B (Conc. H2SO4 and heat)
30.A weak acid is one which
- A. is not corrosive
- B. completely ionizes in water
- C. does not produce salt with alkali
- D. slightly ionizes in water
Answer: D (slightly ionizes in water)
31.According to the collision theory of reaction rates, which of the following conditions is not required for two molecules to react? The molecules must
- A. come into contact without loss of energy on colliding with each other
- B. collide with enough energy to overcome the activation energy barrier
- C. collide in an orientation that makes formation of product possible
- D. possess enough speed to overcome intermolecular forces of attraction
Answer: A (come into contact without loss of energy on colliding with each other)
32.The following organic compounds are polymers except
- A. rubber
- B. starch
- C. proteins
- D. fats
Answer: D (fats)
33.A saturated solution at 300C will normally produce crystals at a temperature of
- A. 500C
- B. 400C
- C. 350C
- D. 200C
Answer: D (200C)
34.Catalysts alter reaction rates by
- A. providing an alternative reaction pathway
- B. lowering the energy of reaction
- C. increasing the surface area of reactants
- D. aligning the reactant molecules properly
Answer: A (providing an alternative reaction pathway)
35.The percentage by mass of Oxygen in MgSO4.7H2O is [ Mr of MgSO4.7H2O = 246 ]
- A. 26.0%
- B. 45.5%
- C. 71.5%
- D. 84.0%
Answer: C ( 71.5%)
36.Which of the following household liquids would be effective in treating someone with too much acid in the stomach?
- A. Strong salt solution with pH 7.0
- B. Tomato juice with pH 4.1
- C. Milk of Magnesia with pH 10.5
- D. Black coffee with pH 5.0
Answer: C (Milk of Magnesia with pH 10.5)
37.Isotopes of the same element have similar chemical properties because they have the same number of
- A. nuclides
- B. protons
- C. neutrons
- D. atoms
Answer: B (protons)
38.The number of shared pair of electrons in a molecule of methane is
- A. 2
- B. 4
- C. 6
- D. 8
Answer: B (4)
39.Naturally occurring Boron is made up of 19.9% 10B and 80.1% 11B. The relative atomic mass of Boron is
- A. 21.0
- B. 10.8
- C. 10.5
- D. 10.0
Answer: B (10.8)
40.Which of the following arrangements of elements is in order of increasing ionization energy?
- A. Si, Al, S, P
- B. S, P, Si, Al
- C. Al, Si, P, S
- D. P, Si, S, Al
Answer: C (Al, Si, P, S)
WAEC Essay Chemistry Questions
Q1a(i) Write the chemical formula of alumina.
(ii) In the extraction of aluminium, state one compound that is used;
I. to obtain alumina from Bauxite
II. as solvent for alumina.
(iii) Name the electrodes used in the extraction of aluminium.
(iv) Give one reason why the extraction of aluminium is expensive.
(v) In the extraction of aluminium:
I. name the substance liberated at the anode;
II. write the equation for the reaction that leads to decrease in the size of the anode.
b(i) Give two ions that cause hardness of water.
(ii) State two advantages and two disadvantages of hard water.
c(i) What is meant by destructive distillation of coal?
(ii) Name four products obtained from the destructive distillation of coal.
d(i) Name two gases which can be used to demonstrate the fountain experiment.
(ii) Give the reason why the gases named in 5d(i) are used.
Answer:
a(i) The chemical formula for alumina,(aluminium oxide) is Al2O3
(ii) In the extraction of aluminium,the compound that is used;
I. to obtain alumina from Bauxite – Sodium hydroxide, NaOH
II. as solvent for alumina – Cryolite, Na3AlF6
(iii) The electrodes used in the extraction of aluminium are
– cathode (negative electrode) graphite,
– anode (positive electrode) carbon rods or slabs.
(iv)The extraction of aluminium is expensive due to the high energy requirements of the electrolysis process, which involves purifying bauxite, melting aluminium oxide, and using electricity to break down electrolytes.
(v) In the extraction of aluminium:
I. the substance liberated at the anode is oxygen gas (O₂)
II. the equation for the reaction that leads to decrease in the size of the anode is: C + O2
→ CO2
b(i) Ions that cause hardness of water are Ca2+
and Mg2+
(ii) Advantages of hard water
– strengthening bones and teeth,
– potentially aiding digestion, and
– reducing the risk of cardiovascular disease.
– improves the taste of water due to the presence of the ions.
Disadvantages of hard water
– skin and hair dryness,
– reduced soap effectiveness,
– potential appliance damage, and plumbing issues.
c(i) Destructive distillation of coal is a process of heating coal in the absence of air (or with limited oxygen) to break down its complex molecules into simpler, useful products like coke, coal gas, coal tar, and ammoniacal liquor.
(ii) products obtained from the destructive distillation of coal are:
– coke
– coal gas
– coal tar and
– ammoniacal liquor
d(i) Gases which can be used to demonstrate the fountain experiment are;
– Ammonia, NH3
– Hydrogen chloride gas, HCl
(ii) Ammonia (NH3
) and hydrogen chloride (HCl) are used in the fountain experiment to demonstrate the high solubility of gases in water. When water is introduced into a flask containing either gas, the gas dissolves rapidly, creating a pressure drop that forces water upwards, forming a “fountain”.
Q2.a) Write a balanced chemical equation for each of the following reactions:
(i) ammonia gas with copper(II) oxide;
(ii) ammonia gas with oxygen gas;
(iii) aqueous potassium iodide with chlorine gas;
(iv) iron with dilute tetraoxosulphate (VI) acid;
(v) aqueous lead(II) trioxonitrate (V) with hydrogen chloride gas.
b(i) Describe briefly the process involved in the extraction of tin from tin ore.
(ii) Mention three uses of hydrogen.
(iii) State two physical properties of hydrogen.
(c) State the class of oxide to which each of the following compounds belong:
(i) Na2O; (ii) ZnO; (iii)SO2; (iv) CO2; (v) N2O.
Q3.(a) What is an electrochemical cell?
(b) State three differences between an electrochemical cell and an electrolytic cell.
(c) Explain briefly what would be observed when powdered zinc is added to a solution of copper (II) tetraoxosulphate (IV) in a beaker.
d(i) Write an equation for the reaction in 1(c);
(ii) State the type of reaction which took place in 1(c);
(e) Name two gases which should be prepared in a fume chamber.
(f) Give three factors that favour cracking.
(g) Give the reason why noble gases are chemically inert.
(h) State four properties of a homologous series.
(i) What is global warming?
(j)State one cause of global warming.
Answer:
(a) An electrochemical cell is a device that can generate electrical energy from the chemical reactions occurring in it, or use the electrical energy supplied to it to facilitate chemical reactions in it.
(b)
| Electrochemical cell | Electrolytic cell |
| Chemical reaction produces electric current | Electricity is used to produce chemical reaction |
| The positive electrode is cathode | Cathode is the negative electrode |
| Anode is the negative electrode | Anode is the positive electrode |
| It does not require any external source of energy. | It does require an external source of energy, thus it is non-spontaneous |
| Electrodes are in separate compartments | Electrodes are in the same compartment |
(c) When powdered zinc is added to a copper (II) tetraoxosulphate (IV) solution, a reddish-brown solid of copper metal will form on the zinc, and the blue solution will become colourless as zinc displaces copper.
d(i) The reaction can be represented by the following equation: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s).
(ii) Oxidation-Reduction (Redox) reaction
(e) Ammonia, Chlorine, Hydrogen Sulphide
(f) Factors that favor cracking include: high temperatures, high pressures, the presence of catalysts, and the nature of the material’s composition and structure.
(g) Noble gases are chemically inert because their outermost electron shells are completely filled, making them stable and unlikely to react with other elements.
(h) Properties of homologous series include the following:
– All members of a homologous series have the same general formula.
– All members of a homologous series have the same functional group. e.g Alcohols contain the (-OH) functional group.
– The molecular formula of successive members of a homologous series differs by CH2.
– Members of a homologous series have similar physical properties, such as melting point, boiling point, and density.
– Members of a homologous series have similar chemical properties because they have the same functional group.
(i) Global warming is the increase in Earth’s average temperature caused by greenhouse gases. Greenhouse gases trap heat in the atmosphere, which warms the planet. Carbon dioxide, methane, and nitrous oxide are greenhouse gases that trap heat in the atmosphere.
(j) Global warming is primarily caused by
– burning of fossil fuels
– increased concentration of greenhouse gases, like carbon dioxide (CO2)
How to pass WAEC exams
It’s important to make your West African Senior Secondary School Certificate Examination a huge success. The following ways are beneficial to candidates that wish to pass WAEC with flying colors:
1. Make adequate Preparation: By preparing very well for the WAEC Chemistry Objectives and theory exams, candidates will be able to write the exams confidently.
2. Attending Extra moral Classes: The school teachers might not be able to complete the curriculum on time. On that note, it is advisable for students to attend tutorials that will enlightened the more on the right topics under The syllables.
3. Make good use of Past Questions: The West African Examination Council, WAEC has a pattern of setting questions. Students that make good use of the WAEC Chemistry past Questions and Answers will surely perform well in the exams. Try and practice the questions set on previous years.
4. Use WAEC Chemistry Syllabus: The WAEC Chemistry Syllabus has a list of topics to be treated for years. Candidates should ensures that they use the syllabus while studying and preparing for their exams.
Steps to Answer Questions
The following steps are crucial while trying to answer WAEC Chemistry questions:
- Candidates are advised to always begin with the simplest questions.
- Adherence to the WAEC exams instructions are very important.
- All the required details should be carefully written or entered on the WAEC Answer booklet.
- Candidate’s handwriting should be very readable.
- It’s important to attempt the required number of questions.
- Candidates should cross check their answers before final submission.
Conclusion
Passing the WAEC Chemistry exams is very easy. All that is required is to do the needful. Prepare on time, attend tutorials, use past Questions and syllabus and many more.
Those that want to know more about the WAEC Chemistry questions and Answers should use the comments box hereunder.
Similar Post
- WAEC Timetable
- WAEC Data Processing Questions and Answers
- WAEC Literature in English Questions and Answers
- WAEC Government Questions and Answers
- WAEC Marketing Questions and Answers
- WAEC English Language Questions and Answers
- WAEC Biology Practical Questions and Answers
- WAEC Agric Science Questions and Answers
- WAEC Mathematics Questions and Answers
- WAEC Biology Questions and Answers
- WAEC Economics Questions and Answers
