Category: Chemistry

The Existence of Chemicals

  1. Soaps, detergents, food additives and medicines play an important role in our life.   2. These chemicals have helped us to improve the quality of life. However, these chemicals can cause side effects on life and the environment if they...

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Medicine

  1. A medicine is used to prevent or cure a disease or to relieve pain.   2. Medicines can be classified into traditional medicines and modern medicines.   Traditional medicine 1. Traditional medicines are derived from plants...

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Food Additives

  A food additive is a natural or synthetic substance which is added to food to prevent spoilage or to improve its appearance, taste or texture.   Types of food additives and their functions 1. Food additives that are commonly used...

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Heat of Combustion

  1. A fuel is a chemical substance that burns in oxygen to produce heat energy.   2. Combustion is a chemical reaction between a fuel and oxygen to release heat. Combustion is always an exothermic reaction.   3. The heat of...

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Soap and Detergent

  What is soap? 1. Soaps are sodium or potassium salts of long-chain fatty acids.   2. The general formula of a soap can be written as \(RCOO^-Na^+\) or \(RCOO^-K^+\), where R is an alkyl group usually containing 12 or 18...

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Order in Homologous Series

  1. Photograph 2.6 shows the first members of various homologous series.   2. Alkanes, alkenes, alcohols, carboxylic acids and esters belong to different homologous series. The organisation of organic compounds into the various...

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