Notesale: Turn your study into money

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Introduction to Chemistry
What is Chemistry?
-This is a branch of science in which the composition and properties of matter are studied
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Extraction of chemicals from plants
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Manufacturing of substances for example soap, glass, plastics, medicine, rubber used to
make tires, clothes, cooking oils from naturally occurring substances
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Purification of substances for example water
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It is a career subject for example one can become a scientist, pharmacist or a doctor
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It helps us to understand our environment and how we can relate with it
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Helps us to know how to interact with our environment hence be able to control
pollution
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-There are three states of matter which are: Liquids, solids, gases
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The liquids have definite mass and volume however; they take the shape of the container
in which they are in
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What is a drug?
-A drug is a substance which is used as medicine and alters the way our body normally functions
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-Drugs are administered in specific dosages as prescribed by a medical doctor
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Apparatus
-Study of chemistry involves practice activities in form of experiments performed using
chemicals and apparatus kept in a laboratory
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Sources of heat
-The pieces of apparatus used as sources of heat include: Bunsen burner, spirit lamp, candle, gass
stove, kerosene store and electric heater
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The Bunsen burner
-It consists of three major parts that is: chimney, collar and base
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-The collar is a metal ring with an air hole whose diameter is the same size as that of the
chimney
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-The Bunsen burner is normally connected to an external source of laboratory gas by rubber
tubing
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Rubber Tubing-It connects the gas inlet to an external source of the laboratory gas
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Collar- It is used to regulate the amount of air entering the chimney
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Chimney-This is where the Bunsen burner is ignited to produce a flame which is used to
provide heat through the chimney
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When in use a Bunsen burner produces two types of flames
depending on the amount of air allowed into the chimney
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The flame produced is bright yellow and it’s very large
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- The color of the flame is not uniform and has four zones which cannot be seen
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-The almost colorlessness of the flames, consist of mainly of unburned gasses
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The unburned carbon particles produce black soot which makes
operators dirty on heating
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-In the thin outer region the gas burns completely because it mixes with plenty of air
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-When the air hole is slowly opened more air enters the chimney
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-The mixture of gasses burns more quickly and the flame obtained is blue in color a nonluminous flame
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-It has three regions
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-The almost colorless consists of unburned gasses
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In the outer pale blue region gasses burn
completely because there is plenty of air
-The nonluminous flame gives out only a little light because it doesn’t contain white hot carbon
particles
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-The apparatus used for measuring volume of liquids include a graduated beaker and flask, a
measuring cylinder, volumetric flask, syringe, pipette and burette
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-Graduated beakers, flasks and measuring cylinders are used to measure approximate volumes of
liquids
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Apparatus for measuring temperature
-Temperature is measured using thermometers
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Apparatus for measuring mass
-Mass is measured using weighing balances
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Apparatus for measuring time
-The apparatus for measuring time are watches and clocks
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Some of the common types are analogue
stopwatch and digital stop watch
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Liquids that don’t mix ex: water and
oil
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Flat-bottom flask- Used for general laboratory experiments ex: dissolving substances, heating
solids
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Deflagrating spoon- Used for holding substances being burned
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Thistle funnel- Used for delivering liquid substances
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Dropping funnel- Used to add controlled amounts of liquids into reaction vessels
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Test tube rack- Used for holding boiling tubes and test tubes
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Filter funnel- Used for delivering liquids carefully into vessels
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Spatula- Used for scooping solid substances from containers
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Pipe clay triangle- Used for supporting crucibles during heating
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Spatula- This is used for scooping solid substances from containers
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Wire Gauze- This is used when glass is being heated or burned
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Reagent bottles- This is used for storing chemicals in liquid state
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Crucible- This is used when heating solid substances that require storing heat
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Pestal & Mortar- A pestle is used for crushing substances while a motor holds the substances
being crushed
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Never run while in the laboratory because you may trip, fall and injure yourself or users
of the laboratory
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Never taste or eat anything in the laboratory to avoid poisoning
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Always consult your teacher before trying any experiment to avoid accidents
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Label all the chemicals you are using to avoid confusion
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Always use clean spatulas for scooping a substance from a container to prevent
contamination
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Always hold test-tubes or boiling tubes using a test tube holder when heating to avoid
being burned
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When heating a substance in a test tube or boiling tube, never let the open end face you or
anybody else because the liquid may spurt out and cause injury
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Never look directly into flasks and test tubes where reactions are taking place, because
chemicals may spurt our and cause injury
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Never smell gasses directly, instead waft the gas towards your nose with your hand
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Experiments in which poisonous gasses are produced must be carried out in the fume
cupboard or outdoors
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Always keep flammable substances away from flames because they easily catch fire
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Report any accidents to the teacher or the laboratory technician immediately for
necessary action
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In case of a serious accident such as a fire, calmly walk out
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Doing so would hinder easy escape
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Always extinguish flames that are not in use to avoid accidents and minimize fuel
wastage
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If a chemical gets on your skin or in your mouth rinse it immediately with a lot of clean
water
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Chemicals already used must always be disposed of safely to avoid contamination
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Always work on a clean bench
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