Alfred Ajibola
- 14th October, 2026 @ 06:51 PM
Topics in Chemistry
Chemistry Scheme of Work, SS1 Third Term Chemical Industries: Petrochemicals, Biodegradable, Non-biodegradable Wastes and Pollutants Chemical Industries: Types, Advantages, Disadvantages and Factors affecting Chemical Industries Hydrocarbons: Fractional Distillation of Crude oil and Uses of its Fractions Hydrocarbons: Sources, Classification and Test for Saturated and Unsaturated Hydrocarbons Trioxocarbonates: Preparation, Physical and Chemical Properties, Tests and Uses of Trioxocarbonates Carbon and its Compounds: Oxides of Carbon, Carbon(IV) oxide Carbon and its Compounds: Oxides of Carbon Amorphous Allotropes of Carbon Carbon: Structure and Allotropes of Carbon Salts in Chemistry: Types, Properties, and Uses of Salts Salts in Chemistry, their Classifications, Solubility, Preparations and Colors pH Indicators, Types of Indicators and Importance of pH and pOH Relative Acidity and Alkalinity (pH Scale), and Calculations on pH Bases and Alkalis: Definitions, Classification, Physical and Chemical Properties Bases: Preparation of Bases and Alkalis, Test and Uses Physical and Chemical Properties of Acids, Preparation, Test and Uses of Acids. Acid: Definition, Basicity, and Types of Acid Families of elements in the periodic table Periodic table and Classification of ElementsAcademic Questions in Chemistry
With regards to redox reactions, which of the following statement is wrong?
A. Redox reaction are examples of chemical change
B. Reduction is the gain of electron
C. Substances that donates election during chemical reaction are termed reductants
D. Oxidizing agents are always reduced in chemical reactions
E. Oxidation occurs at the cathode in electrolysis
F. Hydrogen is a reducing agent
In chemistry, physical change is associated only with the rearrangement of molecules while the internal composition of the substance remains the same.
A. True
B. False
_____ electron(s) is a term that describes the number of electron(s) in the outermost shell of an atom.
A. Outer
B. Excess
C. Valence
D. Positive
E. Negative
F. Last
_____ is the negative electrode in electrolysis.
A. Anode
B. Anion
C. Cathode
D. Cation
E. Ion
F. Electrolyte
The above diagram shows the _____ type of bond.
A. Covalent
B. Polar covalent
C. Coordinate covalent
D. Metallic
E. Van dear walls
F. Ionic
Metals are referred to as _____ in their impure state.
A. Diluted
B. Consecrated
C. Coloured
D. Ores
E. Stained
F. Strained
Metals generally have the quality to shine, glow, sparkle, glitter, reflect light and be polished. This characteristic of metals is termed _____.
A. State
B. Ductility
C. Luster
D. Malleability
E. Hardness
F. Inflorescence
The _____ spectrometry experiment conducted on isotopic elements gave a confirmation for the existence of isotopes.
A. Mole
B. Volume
C. Weight
D. Number of moles
E. Mass
F. Amount of substance
A chemical industry is defined as an industry that uses chemical processes (such as reactions, extraction, purification, and synthesis) to convert raw materials into useful finished or semi-finished products on a large (commercial or industrial) scale.
Chemical industries apply the principles of chemistry, reaction kinetics, equilibrium, and thermodynamics, combined with engineering, to manufacture products ranging from basic chemicals to complex consumer goods.
Please read on rate of chemical reaction here.
Chemical industries can be classified in different ways: These are:
1. By Scale of Production
They include heavy chemical industries, light chemical industries and fine chemical industries.
Heavy chemical industries produce large quantities of basic chemicals (in bulk) used mainly as raw materials for other industries. For example, heavy chemical industries are involved in the production of sulfuric acid, ammonia, sodium carbonate, cement, etc.
Light chemical industries are involved in the production of consumer and light-commercial products derived from chemical processes. Such products are formulated, and include everyday products like soaps, detergents, cosmetics, paints, dyes, perfumes, pesticides and basic pharmaceuticals.
Fine chemical industries are involved in the production of smaller quantities of more specialized, often high-value products. This industry manufactures complex, single-molecule or high-purity chemical substances in limited volumes (usually under 1,000 tons per year) with strict specifications. Examples of products manufactured by fine chemical industries include active pharmaceutical ingredients (APIs), analytical reagents, and high-purity synthetic drugs.
2. By Nature of Product and Process
They are classified based on the products manufactured by the industries and the processes involved in their production. They include:
Heavy and light inorganic chemical industries that manufactures (inorganic) products like sulfuric acid (H2SO4) through the contact process, ammonia (NH3) through the haber process, sodium carbonate (Na2CO3) through the solvay process, and chlor-alkali industry that manufactures sodium hydroxide and chlorine (NaOH and Cl₂).
Petrochemical industries uses crude oil and natural gas as raw material, producing plastics, synthetic fibers, solvents, and fuels like petrol, kerosene, diesel, etc.
Fertilizer industries are involved in the production of nitrogenous, phosphatic, and potash (NPK) fertilizers.
Agrochemical industries produce pesticides, herbicides, fungicides for controlling weeds and crop pests.
Pharmaceutical industries produce drugs and medicines.
Polymer/plastics industries are involved in the production of synthetic polymers, rubber, and fibers.
Cement and building material industries produce materials like cement, lime and glass.
Food and beverage processing industries utilizes chemical processes like fermentation and preservation in the production of food and drugs.
Dye and paint industries manufactures pigments, dyes, paints, varnishes.
Metallurgical/extractive industries are involved in the extraction and refining of metals from their ores.
Soap and detergent industries uses the saponification reaction to manufacture soap.
Several factors determine where a chemical industry is sited. They include the following:
Availability and proximity of raw materials: Industries are often sited close to the source of bulky/heavy raw materials (in order to reduce transport costs). For example cement factories are built near limestone deposits.
Availability of water supply: Many chemical processes need large quantities of water for reactions, cooling, and cleaning. Such industries are sited close to a clean and regular water supply source.
Availability and cost of power and energy (e.g, electricity, gas): Energy-intensive industries (e.g. aluminum smelting, electrolytic industries) need cheap, stable and reliable power sources. They are sited in areas with regular power supply.
Transportation and accessibility: Industries are preferably sited in areas with good road network, rail, sea, or pipeline access for bringing in raw materials and moving out finished products.
Availability of labor: Skilled and unskilled workforce within a particular location may influence the siting of related industry in that location.
Market proximity: This refers to closeness of chemical industries to the consumers (or market) so they can easily have access to finished products, consequently reducing distribution costs, especially for perishable or bulky finished products.
Please read on salts in chemistry, types, properties and uses here.
Government policy and incentives: Tax breaks, industrial zones, subsidies, and regulations can attract (or discourage) siting of industries. Low taxation will likely attract the siting of industries in a particular location.
Land availability and cost: The presence of enough and affordable land for factory buildings, storage, and future expansion will promote the siting of chical industries.
Environmental and safety considerations: There is a need to site hazardous industries away from densely populated residential areas. This need affects the siting of chemical industries, creating access to safe waste disposal.
Climatic conditions: Certain industrial processes are sensitive to temperature and humidity, thus affecting their siting.
Capital availability. The availability of capital can influence the siting of chemical industries in choice locations. For example industries with access to funding and investment may be sited in a highly developed area.
Please read the introduction to acids, basicity and types of acids
Raw materials for chemical industries are defined as unrefined (or basic starting substances) derived from organic, inorganic, natural or synthetic sources, and must undergo chemical and physical transformation in order to manufacture intermediate or finished products.
Raw materials for chemical industries are broadly grouped as organic or inorganic:
1. Organic Raw Materials
Organic raw materials are derived mainly from living organisms or their remains (fossil fuels). They are rich in carbon-based compounds: They include the following:
Petroleum (crude oil) and natural gas: These are sources of hydrocarbons for fuels (e.g petrol, kerosene, diesel), plastics, solvents, fertilizers, etc.
Coal: They serve as sources of coke, coal tar, and coal gas (through its destructive distillation).
Please read more on the amorphous allotropes of carbon (coal and coke) here.
Agricultural plant products: They are derived from plants. Examples include starch, cellulose, vegetable oils, sugarcane (for ethanol/fermentation industries), cotton, etc.
Animal products: They are derived from animals. Examples include fats, oils, milk, eggs, hides and skin, etc.
Wood: They are processed in paper/pulp industries.
2. Inorganic Raw Materials
They are derived mainly from mineral or non-living sources. These include:
Minerals and ores: Examples are limestone (CaCO₃) for cement/lime industry, rock salt/brine (NaCl) for chlor-alkali industry, sulfur/pyrites for sulfuric acid, bauxite for aluminum industry, iron ore for steel industry and phosphate rock for fertilizers.
Air: They serve as sources of nitrogen and oxygen. Nitrogen is required for the haber process (in the production of ammonia).
Water: It serves as a universal solvent in reactions (because it dissolves more substances than any other liquid, though it does not dissolve everything). It can also serve as a source of raw material (e.g. in the production of hydrogen gas).
Atmospheric gases: It is comprised of nitrogen, oxygen, carbon(IV) oxide , water vapor, etc. Oxygen is an atmosphere gas extracted from the atmosphere (air) by fractional distillation of liquid air.
Please read on the oxides of carbon
Chemical industries provide employment opportunities for large number of people.
They contribute significantly to a country's economy (GDP, foreign exchange through export earnings, government revenue via taxes, etc).
They produce essential goods that improve standard of living. Examples of such essential goods include medicines, fertilizers (for food production), clothing (synthetic fibers), building materials, fuels, etc.
Chemical industries drive technological advancement, scientific development and innovation. For this reason, advanced countries are industrially developed.
They support other industries by providing raw materials (e.g. plastics for manufacturing industry, fertilizers for agriculture, fuel for cooking and transportation industries).
They encourage infrastructural development such as good roads, constant power supply and modern housing in industrial areas.
Chemical industry is the backbone of the pharmaceutical industry, supplying active ingredients, disinfectants, chlorine for water purification, and life-saving treatments.
Chemical industries pollute the environment through air, water, and land pollution from industrial waste, emissions, and effluents.
Working in chemical industries can cause health hazards, illness or disease due to exposure of workers and nearby residents to toxic chemicals. Such health hazards can include respiratory diseases, skin conditions and poisoning.
They can bring about industrial accidents and hazards through risk of explosions, fires, chemical spills/leaks (e.g. gas leaks), which can cause loss of life and property.
Chemical industries utilize natural resources, consequently bringing about their depletion. For example, non-renewable minerals like fossil fuels are being used up more rapidly (unsustainably) than their formation.
They bring about habitat destruction through land clearing and mining of raw materials. These industrial processes can destroy natural ecosystems.
Chemical industries contribute to global problems through greenhouse gas emissions (global warming) and depletion of the ozone layer (from certain chemicals like CFCs).
They can bring about social disruption through rapid industrialization which can result to overcrowding, displacement of communities, alongside social and economic inequality.
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Amazing facts in Chemistry
Plastic and Glass can decompose, but not in our lifetimes. It takes an average time of 450 years for plastics to decompose. As for the decomposition of glasses, it takes about 4,000 years
The only letters that failed to appear on the periodic table are letters:
Gold and copper are the only two non-silvery colored metals.
Copper is the only metal that is naturally antibacterial. For this reason, some children utilize 'copper water bottles' in schools
Water freezes faster when it’s warm than when it’s cold
Most element in their pure state exists physically in different forms. For instance, pure carbon can exist as both diamond and graphite. This phenomenon is called allotropy
If you pour a handful of salt into a full glass of water, the water level will go down rather than overflowing the glass.
Similarly, if you mix half liter of water and half litre of alcohol, the total volume of the liquid will be les than one litre
Notable points in Chemistry
Below are the physical properties of metals:
They exist in solid state.
The have high densities.
They are good conductors of heat and electricity.
The have the ability to be polished, to glow, sparkle and reflect light.
They can be bent, flattened and made into sheets called foils.
They can be drawn into wires.
Iron undergoes magnetism while most metals are poorly magnetized.
They typical have high melting point.
They generally have high boiling point.
With the exception of lithium, sodium and potassium, most metals are generally hard.
They have the ability to make sound when in contact with other objects or metals.
Please read details on the physical properties of metals here
John Dalton is an English chemist who brought clarity into the composition of matter and the basis for their chemical reactions.
Below are Dalton's Atomic Theory:
All matter consists of tiny indivisible particles called atoms.
Atoms of the same element are identical to each other in every aspect because they have the same shape and mass, while atoms of different elements are different in all respect.
Atoms are indestructible and can neither be created nor destroyed.
Atoms of different elements can combine with each other in simple whole number ratios to form compounds.
Atoms of the same element share similar physical and chemical properties. They can also combine in more than one ratio to form two or more compounds.
Meanwhile, understand that the above theories of John Dalton had been modified.
Please read on Dalton's atomic theory and its modifications here
The periodic table, also called periodic table of elements or Mendeleev's table, is a table that shows an organized arrangement of the 118 chemical elements according to their atomic number.
Out of the 118 elements; elements 1 - 94 are present in nature while elements 95 - 118 are synthesized artificially.
The manner at which elements are arranged on this table reveals some similarities in their electronic configurations and chemical properties.
A compound composed of iron (Fe) and oxygen (O) was analyzed and found to contain 69.94% iron and 30.06% oxygen. Find the empirical formula of the compound. (Molar mass of Fe=55.85, O=16)
Step 1: Identify the given parameter from the question.
Fe = 69.94%, O = 30.06%.
Empirical formula = Fe?O?
Step 2: Convert the percentages to gram. (just attribute grams to the %).
Step 3: To get the mole ratio of each element, convert the gram to moles using the formula (mole = mass/molarmass). Please merorize this formula because we always work with moles in emperical formula.
Mole of Fe: 69.94/55.85 = 1.252mol
Mole of O: 30.06/16 = 1.879mol
Step 4: Divide both sides by the smallest mole ratio.
Iron has the smallest mole ratio in our case, therefore: 1.252/1.252 = 1, 1.879/1.252 = 1.5
We now have the formula = Fe1O1.5
Step 5: Multiply each of the moles by the smallest whole number that will convert each into a whole number. (In our case, the number '2' is the smallest whole number that will make '1.5' and '1' whole numbers when multiplied by it.
For iron (Fe), we will have 1 x 2 = 2
For oxygen (O), we will have 1.5 x 2 = 3
Step 6: Write the empirical formula.
The empirical formula= Fe2O3
Iron(III)tetraoxosulphate(VI)
In chemistry, hydrocarbons can be classified as either aliphatic or aromatic. Recently, both classifications of hydrocarbon were based on their structure rather than their origin.
Aliphatic hydrocarbons are put into three main groups according to the types of bonds they possess. These are:
Alkanes
Alkenes
Alkynes
They are shown in the image below:
It's important to note the followings:
Alkanes have single bonds (only) in their structures.
Alkenes always have a carbon-carbon double bond present in their structure.
Alkynes always have a carbon-carbon triple bond present in their structure.
Aromatic hydrocarbons are classified into:
