Category: O-level chemistry


06/05/2021 2

Genotype This is the genetical constitution of an organism i.e. the particular set alleles, leading to observable characteristics Please Subscribe to promote this website. Subscription ... Read More

Preparation of hydrogen

07/11/2020 4

procedure of preparation of hydrogen and worked examples Read More

Preparation of oxygen with worked examples (O-level chemistry)

07/08/2020 3 principles of preparation of gases i.e. preparatory state, purification stage, drying stage, and collection stage. Preparation oxygen, sample questions and answers Read More

Preparation of gases, hydrogen (o-level chemistry)

06/24/2020 2 Stages of gas preparation, preparation of oxygen, testing for oxygen Read More


05/20/2020 2

Addition examples of calculations involving molarity Read More

Calculation involving s.t.p and r.t.p in ordinary level chemistry- video

05/20/2020 1

Calculations involving standard temperature and pressure (s.t.p) and room temperature and pressure (r.t.p) Read More

Reactivity series (o-level chemistry)

04/26/2020 1

Reactivity series: Some metals are more reactive than others. A list of metals with the most active at the top and the least active at ... Read More

Reactivity series (o-level chemistry)

04/09/2020 0

Reactivity series: Some metals are more reactive than others. A list of metals with the most active at the top and the least active at ... Read More

Electrolysis (O and A-level chemistry)

02/14/2020 1

Electrolysis This is the decomposition of an ionic compound in molten or solution form to its constituent elements. Mechanism of electrolysis Consider electrolysis of molten ... Read More

Moles, mass, gas volumes and equations, s.t.p, r.t.p (O-level chemistry)

01/09/2020 2

The mole A mole of a substance is the mass in grams of the substance which is numerically equal to its relative atomic mass or ... Read More

Percentages (O-level chemistry)

01/09/2020 0

PERCENTAGE We calculate the percentage of an element in a compound if we know the relative atomic masses e.g.   Example 1   What is ... Read More

Action of metals with water (O-level chemistry)

01/09/2020 1

Action of metals with water Most metals react with water to produce hydrogen and the hydroxide of the metal The table below show action of ... Read More

Heat/enthalpy of reaction (O-level chemistry)

01/09/2020 1

Calculations involving heat in reactions The reaction involves energy change; exothermic reactions such as burning firewoods produce heat while endothermic reactions such as the dissolution ... Read More

THE EMPIRICAL FORMULA (o-level chemistry)

01/09/2020 3

THE EMPIRICAL FORMULA The empirical formula of a compound is the simplest formula, which shows the ratio of the atoms present in a compound or ... Read More

Organic chemistry (O-level chemistry)

01/09/2020 1

O-level organic chemistry Organic chemistry is the study of compounds of carbon Uniqueness of carbon Carbon forms very many useful compounds with different physical and ... Read More

Balancing equations (O-level chemistry)

01/09/2020 3

FORMULAE & EQUATIONS Meaning of an equation, if we consider the following equation: Zn(s)  +  H2SO4(aq)       →  Zn SO4(aq)  +  H2(g) 65          (2 + ... Read More

Hygroscopic, deliquensce, efflorescence (O-level chemistry)

01/09/2020 0

Three ways in which the atmosphere may react with substance: 1.         Hygroscope A hygroscopic substance is one, which absorbs water from the atmosphere e.g. copper ... Read More

Salt (O-level chemistry)

01/09/2020 2

SALTS A salt is a compound formed when the replaceable hydrogen atom(s) of acid is replaced by a metal or ammonium ion (NH4+) Types of ... Read More

Preparation of gases (O-level chemistry)

01/09/2020 1

Gases LABORATORY PREPARATION OF GASES Four main stages involved when preparing a gas in the laboratory. Production stage: here the reaction occurs in the reaction ... Read More

Separation of mixtures (O-level chemistry)

01/08/2020 0

Separation of mixtures A mixture is a substance, which consists of two or more substances/elements or compounds NOT chemically combined together. Examples of mixtures include;- ... Read More

Water of crystallization (O-level chemistry)

01/08/2020 0

WATER OF CRYSTALISATION: This is the amount of water, which must be present in order for a solid to form crystals.  When this water of ... Read More

Qualitative analysis (o-level chemistry)

01/08/2020 0

Qualitative analysis This is a branch of chemistry that requires the use of known chemicals and reagents called bench reagents to identify unknown chemicals or ... Read More

Period table and bonding (O-level chemistry)

01/08/2020 1

The Periodic Table (PT) The periodic table is a tabular arrangement such that the columns contain elements with electronically similar atoms. The rows of the ... Read More

Hard water and water pollution (O-level chemistry)

01/08/2020 1

Hard water Hard water: is water which does not form lather easily with soap. This is due to the formation of insoluble precipitates (scum) when ... Read More

Extraction of metals (O-level chemistry)

01/07/2020 0

General principles of extraction of metals Occurrence of elements in nature Elements occur in two state Native or free especially less reactive, Au, Ag, Cu, ... Read More

Rusting (O-Level chemistry)

01/07/2020 1

For revision questions and answers download PDF below: rewrite the notes to possess them Rusting-of-iron chemistry RUSTING OF IRON When iron is left in damp ... Read More

Rates of reaction (O-level chemistry)

01/07/2020 0

For revision questions and answers download PDF; rewrite the notes to understand. Rates-of-reaction-o-level chemistry Rates of reaction Rate of a chemical reaction: Is the amount ... Read More

Electrolysis (O-level chemistry)

01/07/2020 3

Electrolysis This is the decomposition of an ionic compound in molten or solution form into its constituent elements by electricity. Note that An electrolyte is ... Read More

Kinetic theory (O-level chemistry)

01/07/2020 0

KINETIC THEORY States that “mater is made of small particles that are in a continuous random motion” The particles move fastest in gases and slowest ... Read More

Carbon and its compounds (O-level chemistry)

01/07/2020 2

Carbon and its compounds Carbon exists in 3 allotropic forms, diamond, graphite and amorphous carbon (charcoal, lampblack, soot, and coke) diamond and graphite are crystalline ... Read More

Chlorine and its compounds (O-level chemistry)

01/06/2020 1

Halogens or Group 7B elements These are fluorine, chlorine, bromine, iodine and astatine.  Table 14.0 gives some properties of group 7B elements. Table 14.0  Some ... Read More

Sulphur and its compounds (O-level chemistry)

01/06/2020 1

Sulphur Sulphur occurs naturally in three forms: 1. Free form in Japan, Texas and Louisiana. Extraction of sulphur In order to extract this underground sulphur ... Read More

Nitrogen and it compounds (O-level chemistry)

01/05/2020 2

Nitrogen and its compounds (O-level) Source: Air Industrial preparation of nitrogen By distillation of air from which carbon dioxide and water vapor have been removed. ... Read More