This archive section contains everything related to Chemistry and involves the study of the composition, structure and properties of matter. The study of chemistry focuses mainly on atomic and molecular structure and its change, for example through chemical reactions.
What Is Hydrogen Bonding? Hydrogen bonding is the electrostatic force of attraction between a hydrogen atom (which is covalently bonded to a small and highly electronegative atom) and the lone pair of electrons of another small and highly electronegative atom. It is a special type of intermolecular force with some Read more…
Acids, Bases and Salts Question 2 The table below shows the effect of three substances A, B and C on universal indicator solution. substance effect on universal indicator solution A red B green C purple i. State the function of the universal indicator solution. [1] ii. Deduce the nature of Read more…
Acids, Bases and Salts Question 1 Calcium sulphate can be formed by the reaction between calcium carbonate and solution X. Two other substances are produced in this reaction. Name solution X. [1] Name the other two products. [2] Name the type of reaction that occur between calcium carbonate and X. Read more…
Atomic Structure and Bonding Question 1 The mass number of potassium is 39 and its proton number is 19. i. State the number of electrons in the potassium atom. [1] ii. Determine the number of neutrons in the potassium atom. [1] Potassium reacts with chlorine by donating electrons. i. State Read more…
Atomic Structure and Bonding Question 2 Chlorine has two types of atoms as shown, 35Cl and 37Cl.i. State the name given to the two types of chlorine atoms shown. [1]ii. Calculate the number of neutrons in 35Cl. [1] Chlorine reacts with sodium to form sodium chloride (NaCl).i. Name the type Read more…
What are oxidation numbers? An oxidation number or oxidation state is a number assigned to each atom or ion in a compound to show its degree of oxidation. Oxidation numbers can be positive, negative or zero. It is important to note that the + or – sign should always be Read more…
Acids Bases and Salts Questions and Answers (O level Chemistry) Question 1 Acids are neutralised by alkalis. Write the ionic equation for the reaction between an acid and an alkali. Sodium sulphate is a soluble salt that can be prepared using a titration method. (i) Name a sodium compound and Read more…
Some Important Chemical Reactions you should know (O level chemistry) Ionisation of elements Ionisation of Group 1 elements (alkaline metals) Atoms of Group 1 elements have 1 electron in the outer shell, so they ionise by losing 1 electron to form a positively charged ion of charge +1. This is Read more…
How to use the periodic table In this post we are going to discuss on how to use the Periodic Table. To a random person, the Periodic Table might look like just an orderly arrangement of atoms but to a chemist, the Periodic Table is the summary of chemistry. The Read more…
Uses of common elements and compounds This is a list of commonly asked uses of substances in O level Chemistry and Combined Science exams. Uses of oxygen Medical purposes – In hospitals, oxygen is given to some people who are injured or ill with disease that damage the lungs and Read more…