Search Results

Start off your program by giving some basic information about what participants can expect to learn. Introduce the topic and provide a basic outline of what's to come using videos, images, and text.

1. It is advisable to wear a laboratory coat or an apron to protect the clothings. 2. Never taste a chemical or inhale extensively its vapours until you are asked to do so by your teacher. 3. When a chemical is not in use, its container should be closed tightly to prevent it from spilling or its vapours diffusing in air to cause irritation. 4. If a chemical reagent gets into your eyes or mouth or on the skin, wash the affected areas immediately with cold water and report the incident to your teacher or laboratory incharge. 5. In order to neutralise acid spills on the clothing or skin, use a very dilute ammonia or sodium bicarbonate solution. 6. Keep inflammable chemicals like alcohol acetone etc., away from the burner. 7. Never add water to a concentrated acid like sulphuric acid. Such an addition generates a lot of heat which may break the glass container causing a dangerous spill. Always add acid to water slowly, stirring continuously. 8. Never throw a burning matchstick or a burning paper into a sink where it may ignite a discarded flammable liquid. 9. You are required to take extra precautions while heating a chemical or mixture in a glass container. Some of these precautions are briefly described below : (a) To heat a chemical substance in a test tube, apply the flame at the upper layer of the liquid as shown in the figure. Never apply the flame at the bottom of the test tube as it may cause the liquid to boil over. Moreover, the test tube should first be heated gently and then strongly at the outer part of the flame, with continuous shaking. (b) While heating the contents of a test tube be sure to point the open end of the tube away from your classmates and yourself as shown in the figure. 10. Chemicals can be absorbed through the skin. Thus, it is a good habit to wash your hands immediately after they come in contact with any chemical.

Chemistry is an experimental science and involves various types of observations and transformations in substances. It also involves various principles in the making of such substances. Chemistry helps us to understand nature and various life processes. From the beginning of history, people have been fascinated by the world around them. The distinguishing characteristic of humans is the passion to understand their world. That passion has created science. The word science is derived from Latin word scientia which means ‘knowledge’. Thus, science is the term for the broad field of human knowledge concerned with facts that are explained logically by rules, patterns or principles. Areas of Science :Science is divided into separate areas of study, such as astronomy, biology, geology, chemistry, physics and mathematics. Although more recently attempts have been made to combine traditionally separate disciplines under such headings as life sciences and earth sciences. These areas are usually jointly referred to as the natural sciences. The physical sciences comprise mathematics, physics and chemistry. The application of science for practical purposes is called technology.

Early history of Chemistry : Many years before chemistry became a science, people knew how to combine certain substances in order to make things. For example, by 2000 B.C., people of Egypt made bronze by melting tin and copper together. They also made glass, jewellery, perfume and wine. All of these objects involved the production and control of chemical changes. However, the people did not know why these changes took place.

Scientists work to find out the best possible way to find out and solve the problem. This method is known as scientific method and it involves several steps. (i) Identifying the problem. (ii) Gathering all the known information. (iii) Forming a hypothesis on the basis of experimental facts. (iv) Verification by other scientists and formation of theory. (v) Universal acceptance in the form of law. (i) Identifying the problem : Scientists think over a problem i.e., the area where they have to work. (ii) Gathering all the known information : Scientists then find out all the information which is provided to them through books, internet etc. They then mix it with their own knowledge. (iii) Forming a hypothesis : A hypothesis is not simply an idea picked out from somewhere. It offers a possible explanation for an event that has been observed. To test the hypothesis, the scientists design and perform experiments, records, observations and then draw the conclusion. Before the hypothesis is accepted, other scientists have to perform the experiment and get the same results. (iv) Formation of theory : When the hypothesis is widely accepted by scientists and results obtained are similar. The hypothesis is converted to theory. (v) Formation of law : When theory is universally accepted and the results are found to be correct at all instants of time. It is converted to law.

It is a study of substances, their properties, structures and transformations. In other words, Chemistry is the science of the elements. It deals with the properties and chemical reactions of the elements and their compounds (combinations of elements). It also studies the way in which these elements and compounds can be made. It is also concerned with the composition of matter (gas, liquid or solid) and of the changes that take place in it under certain conditions.

Alchemy : Alchemy was one of the earliest forms of chemistry. It combined science, magic, philosophy and religion. Alchemists are the forerunners of present day chemists. They were perhaps the earliest experimentalists. The alchemists tried many ways of changing substances into gold by using “philosopher’s stone” (an illusionary substance). They also tried to produce a substance that would give people a long and healthy life or let them live forever. They found ways of making chemical changes in various substances. They improved methods of taking metals from an ore and learned how to make and use various acids. They also designed laboratory equipment, such as balances, for weighing chemicals.