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Introduction to chemistry
Chemistry is a branch of Science. Science is basically the study of living and non-living things. The branch of science that study living things is called Biology. The branch of science that study non-living things is called Physical Science. Physical Science is made up of:
Physics- the study of matter in relation to energy
Chemistry- the study of the composition of matter.
Chemistry is thus defined as the branch of science that deals with the structure composition, properties and behavior of matter.
Basic Chemistry involves studying:
States/phases of matter
Matter is anything that has weight/mass and occupies space/volume. Naturally, there are basically three states of matter.
(i) Solid-e.g. soil, sand, copper metal, bucket, ice.
(ii)Liquid- e.g. water, Petrol, ethanol/alcohol, Mercury (liquid metal).
(iii) gas- e.g. Oxygen, Nitrogen ,Water vapour.
A solid is made up of particles which are very closely packed. It thus has a definite/fixed shape and fixed/definite volume /occupies definite space. It has a very high density.
A liquid is made up of particles which have some degree of freedom. It thus has no definite/fixed shape. It takes the shape of the container it is put. A liquid has fixed/definite volume/occupies definite space.
A gas is made up of particles free from each other. It thus has no definite/fixed shape. It takes the shape of the container it is put. It has no fixed/definite volume/occupies every space in a container.
(b) Separation of mixture
A mixture is a combination of two or more substances that can be separated by physical means. Simple methods of separating mixtures at basic chemistry level include:
i) Sorting/picking-this involve physically picking one pure substance from a mixture with another/other. e. g. sorting maize from maize beans mixture.
ii) Decantation-this involve pouring out a liquid from a solid that has settled /sinking solid in it. e. g. Decanting water forms sand.
iii)Filtration-this involves sieving /passing particles of a mixture through a filter containing small holes that allow smaller particle to pass through but do not allow bigger particle to pass through.
iv) Skimming-this involve scooping floating particles. E.g. cream from milk
(c) Metals and non-metals full notes Chemistry form one
Metals are shiny, ductile(able to form wires), malleable(able to form sheet) and coil without breaking. E.g. Iron, gold, silver, copper. Mercury is the only liquid metal known.
Non-metals are dull, not ductile (do not form wires), not malleable (do not form sheet) and break on coiling/brittle. E.g. Charcoal, Sulphur, pla-stics.
(d) Conductors and non-conductors
A conductor is a solid that allow electric current to pass through. A non-conductor is a solid that do not allow electric current to pass through.
All metals conduct electricity. All non-metals do not conduct electricity except carbon graphite.
(e) Drugs
A drug is a natural or synthetic/man-made substance that when taken changes/alter the body functioning. A natural or synthetic/man-made substance that when taken changes/alter the abnormal body functioning to normal is called medicine. Medicines are thus drugs intended to correct abnormal body functions. . Medicines should therefore be taken on prescription and dosage.
A prescription is a medical instruction to a patient/sick on the correct type of medicine to take and period/time between one intake to the other.
A dosage is the correct quantity of drug required to alter the abnormal body function back to normal. This is called treatment. It is the professional work of qualified doctors/pharmacists to administer correct prescription and dosage of drugs/medicine to the sick. Prescription and dosage of drugs/medicine to the sick use medical language.
Example
(i) 2 x 4 ; means “2” tablets for solid drugs/spoonfuls for liquid drugs taken “4” times for a duration of one day/24 hours and then repeated and continued until all the drug given is finished.
(ii) 1 x 2 ; means “1” tablets for solid drugs/spoonfuls for liquid drugs taken “2” times for a duration of one day/24 hours and then repeated and continued until all the drug given is finished.
Some drugs need minimal prescription and thus are available without pharmacist/ doctor’s prescription. They are called Over The Counter (OTC) drugs. OTC drugs used to treat mild headaches, stomach upsets, common cold include:
(i) Painkillers
(ii) Anti-acids
(iii) cold/flu drugs.
All medicine requires correct intake dosage. When a prescription dosage is not followed, this is called drug misuse/abuse. Some drugs are used for other purposes other than that intended. This is called drug abuse.
Drug abuse is when a drug is intentionally used to alter the normal functioning of the body. The intentional abnormal function of the drug is to make the victim have false feeling of well being. The victim lack both mental and physical coordination.
Some drugs that induce a false feeling of well being are illegal. They include heroin, cocaine, bhang, Mandrax and morphine.
Some abused drugs which are not illegal include: Miraa, alcohol, tobacco, sleeping pills.
The role of chemistry in society
(a) Chemistry is used in the following:
(i) Washing/cleaning with soap:
Washing/cleaning is a chemical process that involves interaction of water, soap and dirt so as to remove the dirt from a garment.
(ii) Understanding chemicals of life
Living thing grow, respire and feed. The formation and growth of cells involve chemical processes in living things using carbohydrates, proteins and vitamins.
(iii) Baking:
Adding baking powder to dough and then heating in an oven involves interactions that require understanding of chemistry.
(iv) Medicine:
Discovery, test, prescription and dosage of drugs to be used for medicinal purposes require advanced understanding of chemistry
(v) Fractional distillation of crude oil:
Crude oil is fractional distilled to useful portions like petrol, diesel, kerosene by applying chemistry.
(vi) Manufacture of synthetic compounds/substances
Large amounts of plastics, glass, fertilizers, insecticides, soaps, cements, are manufactured worldwide. Advanced understanding of the chemical processes involved is a requirement.
(vii) Diagnosis/test for abnormal body functions.
If the body is not functioning normally, it is said to be sick/ill. Laboratory test are done to diagnose the illness/sickness.
(b) The following career fields require Chemistry as one of subject areas of advanced/specialized study:
(i) Chemical engineering/chemical engineer
(ii) Veterinary medicine/Veterinary doctor
(iii) Medicine/Medical doctor/pharmacist/nurse
(iv) Beauty/Beautician
(v) Teaching/Chemistry teacher.
The School Chemistry Laboratory
Chemistry is studied mainly in a science room called a school chemistry laboratory. The room is better ventilated than normal classroom. It has electricity, gas and water taps. A school chemistry laboratory has a qualified professional whose called Laboratory technician/assistant.
All students user in a school chemistry laboratory must consult the Laboratory technician/assistant for all their laboratory work. A school chemistry laboratory has chemicals and apparatus.
A chemical is a substance whose composition is known. All chemical are thus labeled as they are. This is because whereas physically a substance may appear similar, chemically they may be different.
All Chemicals which are not labeled should never be used. Some chemicals are toxic/poisonous, explosive, corrosive, caustic, irritants, flammable, oxidizing, carcinogenic, or radioactive.
Care should always be taken when handling any chemical which have any of the above characteristic properties.
Common school chemistry laboratory chemicals include:
(i) Distilled water
(ii) Concentrated mineral acid which are very corrosive (on contact with skin they cause painful open wounds)
(iii) Concentrated alkali/bases which are caustic (on contact with skin they cause painful blisters)
(iv) Very many types of salts
The following safety guideline rules should be followed by chemistry laboratory users:
(i) Enter the laboratory with permission in an orderly manner without rushing/pushing/scrabbling.
(ii) Do not try unauthorized experiments. They may produce flammable, explosive or toxic substances that affect your health.
(iii) Do not taste any chemical in the laboratory. They may be poisonous.
(iv) Waft gas fumes to your nose with your palm. Do not inhale/smell gases directly. They may be highly poisonous/toxic.
(v) Boil substances with mouth of the test tube facing away from others and yourself. Boiling liquids spurt out portions of the hot liquid. Products of heating solids may be a highly poisonous/toxic gas.
(vi) Wash with lots of water any skin contact with chemicals immediately. Report immediately to teacher/laboratory technician any irritation, cut, burn, bruise or feelings arising from laboratory work.
(vii) Read and follow safety instruction. All experiments that evolve/produce poisonous gases should be done in the open or in a fume chamber.
(viii )Clean your laboratory work station after use. Wash your hand before leaving the chemistry laboratory.
