TOPIC 6: AIR COMBUSTION, RUSTING AND FIRE FIGHTING Composition of air Air is a mixture of different gases. The gases that make up the air include nitrogen, oxygen, carbon dioxide, noble gases (argon, helium, neon, krypton and xenon) and a little water vapour. Air may also contain traces of impurities such as carbon monoxide (CO), sulphur dioxide (SO2), hydrogen sulphide (H2S) and other gases. The presence of these gases in air results in air pollution. Table bellow shows the composition of air by volume. The proportion of water vapour and impurities in air is very variable. The Gases Present in…
Author: Msomi Bora
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TOPIC 5: MATTER Concept of matter Concept of Matter Explain concept of matter Matter is anything that has mass and occupies space. Therefore, anything around us provided it has mass and can occupy the space, is termed as matter. There are many kinds of matter. Can you mention some? The word matter is used to cover all the substances and materials from which the earth and universe is composed of. These include all materials around us such as water, soil, plants, animals, air, clothes, etc. Any particular kind of matter is called a substance. Substances include elements and compounds. An…
TOPIC 4: THE SCIENTIFIC PROCEDURE Significance of scientific procedure The Concept of Scientific Procedure Explain the concept of scientific procedure The scientific method (procedure) is a process that scientists use to ask questions and conduct investigations to find answers to these problems. It is a logical approach to problem solving by observing and collecting data, formulating hypotheses, testing hypotheses, and formulating theories that are supported by data. The scientific method provides a standardized way for scientists to conduct their work. However, many scientists work according to other methods as well. The Importance of the Scientific Procedure Explain the importance of…
TOPIC 3: HEAT SOURCES AND FLAMES Heat sources Most chemical reactions require heat to proceed. It is therefore important to have sources of heat in a laboratory for heating various reacting substances. Sources of heat in a chemistry laboratory may include Bunsen burner, candle, spirit burner, kerosene burner (stove), tin lamp (kibatari) and charcoal burner. These are burners commonly used in most school laboratories. Different Heat Sources which can be Used in a Chemistry Laboratory Name different heat sources which can be used in a chemistry laboratory The Bunsen burner is the best of all burners because it is convenient…
TOPIC 2: LABORATORY TECHNIQUES AND SAFETY A laboratory is a room or building specially designed for conducting various scientific experiments. An appropriate school laboratory has the following features: a room with enough space for carrying out scientific experiments; a store for keeping laboratory apparatus, chemicals and reagents; an office for laboratory technician to sit in and design scientific experiments; enough ventilation to let in fresh air and light; wide doors and several exits for emergency evacuation in case of an accident; and a wide table in front of the laboratory room, fitted with sinks for experiment demonstrations by the teacher…
TOPIC 1: INTRODUCTION TO CHEMISTRY The concept of chemistry The Concept of Chemistry Explain the concept of Chemistry Chemistry is a branch of science that deals with the study of nature, properties and composition of matter. Matter can be defined as anything that has weight or mass and can occupy space. Therefore, in chemistry we study materials that make up the earth and universe. These range from living to non-living materials. We apply the knowledge of chemistry to study the composition, behaviour and nature of materials around us. This study enables us to make the best use of these materials…
TOPIC 5 HUMAN IMMUNODEFICIENCY (HIV) ACQUIRED IMMUNE DEFICIENCY SYNDROME (AIDS) AND SEXUALLY TRANSMITTED INFECTIONS (STIS) Relationship Between HIV, AIDS and STIs Defference between HIV, AIDS and STIs Distinguish between HIV, AIDS and STIs HIV/AIDS (Human Immunodeficiency Virus and Acquired Immune Deficiency Syndrome) Acquired means “to get from” this means that AIDS is gotten from other people, “Immune” means “protect”, this means that the body is normally protected against many diseases. Deficiency means “lack: and syndrome means a group of different symptoms of diseases. AIDS is the pandemic disease, which is caused by a certain type of organism called virus. These…
TOPIC 4: EVOLUTION Concept of Organic Evolution The Concept of Organic Evolution Explain the concept of organic evolution Evolution is the gradual development of organisms from simple form to more complex forms over a long duration of time. Evolution is marked by emergence of new species from pre-existing species and the disappearance of some species. The species that disappear are said to become extinct. Key terms used in organic evolution Carbon dating: This is a method of estimating the ages of dead materials of biological origin. Natural Selection: This is selective force occurring in nature, which is responsible for eliminating the unfavourable…
TOPIC 3: CLASSIFICATION OF LIVING THINGS Kingdom Animalia The word ‘animal’ is derived from the Latin word animalis which means ‘having breath’. The Kingdom Animalia is characterized by eukaryotic and heterotrophic organisms. They are multicellular and lack cell wall. They depend directly or indirectly of plants for their food. Food is ingested and digested in their internal cavity and food reserves are stored as glycogen or fat. Nutrition is holozoic, i.e, by ingestion of food. Animals follow a definite growth pattern, the adults have a definite shape and size. Higher forms of animals exhibit well developed sensory and neuromotor mechanism. Most of…
TOPIC 2: GENETICS Concept of Genetics The concept of Genetics Explain the concept of the genetics Genetics is a branch of biology which deals with the study of heredity and variations in organisms. Heredity refers to the transmission of genetic information from one generation to another. That is, the passing on of features or characteristics from parents to offspring or progeny. In humans, for example, features such as hair colour and body shape of the parents can be passed on (inherited) to their children. In genetics, a feature that can be inherited by the offspring from the parent is known as a trait. Thus, features…