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
Chemistry is a fundamental science that plays a crucial role in various fields and applications. In fact, the study and knowledge of chemistry has contributed greatly towards providing our basic needs and improving the quality of our life through the following ways:
The use of fertilisers, insecticides, herbicides and pesticides has helped to increase food production through agriculture. These chemicals function by enhancing crop yield and combating pests and diseases. Chemist also study the soil in order to improve plant growth.
Chemical processes are designed to preserve and store food for a long period of time; so that it can be exported and made available to more people.
Please read on the introduction to chemistry, careers in chemistry and the scientific approach.
Through intensive chemical research, man-made textile fibres are produced. These have made available a wide range of clothing materials for man's use.
Apart from clothing, chemistry is also vital in the manufacturing processes of products such as plastics and chemicals, impacting the economy and consumer goods.
The duty of the military is to defend the territorial integrity of a nation or state. The military cannot do this without ammunition. Chemistry has contributed to the discovery and description of the behaviour of chemical substances such as explosives used by the military. In fact, the gunpowder used by the earliest guns was made by mixing sulphur, charcoal and potassium trioxonitrates (V).
Please read more on nuclear chemistry here.
Chemistry is used in water purification and treatment processes to make water safe for consumption. This process will involve the removal of contaminants and pathogens through elements like chlorine.
In our efforts to gain more knowledge of the other planets and outer space around us, special rockets called space-rockets are sent into space.
The first space rocket was sent into space on October 4, 1957 by Russia. In July, 1969, Apolio 11 Astronauts comprising of Neil Armstrong and Edwin Aldrin landed on the moon, while the module pilot Michael Collins remained in orbit around it in the command module. These were made possible via science and technology.
Please read more on the solar system in Geography here.
To overcome the present need for housing and maximise use of land space especially in cities, many high-rise buildings are being constructed. These buildings need materials like cement, concrete, steel, bricks and tiles which are produced by chemical industries.
Health is wealth. The healthy life that many people enjoy is due to the variety of medicines that are made available as a result of chemical research and technology.
Chemistry is essential in the development of new drugs and therapies. It furthers our understanding on how substances interact in the body, and in synthesizing compounds that can fight against diseases.
Please read on drugs and their side effects here.
Modern transportation system is an essential feature of today's world. This rapid development from carts pulled by animals to the latest air craft was made possible by chemicals producing suitable fuels and structural materials like alloys. which are light, strong and heat resistant.
Please read on the means and mode of transportation here.
Chemistry is involved in developing fuels and alternative energy sources such as solar cells, batteries, and biofuels. It helps optimize energy efficiency and storage.
Fuels like natural gas, petrol, kerosene and diesel are chemicals obtained through the fractional distillation of crude oil. These chemical are very crucial in automobiles, as they are converted to mechanical and kinetic energy respectively.
Please read on fractional distillation of crude oil here.
Chemistry is used in food preservation, alcohol fermentation, flavor enhancement, nutritional analysis, alongside the development of food additives. It also plays a role in nutrition and understanding food safety.
Chemical techniques are used in forensic analysis to identify substances, analyze crime scene evidence, and help solve criminal cases.
You can read on the cell theory here.
Chemists create new materials with specific properties for various applications, including polymers, nanomaterials, and composites used in construction, electronics, and packaging.
This branch of chemistry focuses on chemical processes within living organisms, contributing to our understanding of metabolism, genetics, and disease mechanisms.
Chemistry is essential in formulating cosmetics, skincare products, and cleaning agents, ensuring efficacy and safety.
Please read on the adverse effects of chemistry here.
Since chemistry is the study of matter and the changes they undergo, it therefore has a profound impact on our daily lives and contributes to advancements in technology, health, environment, and various industries.
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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:
