chem topic 1 Flashcards
revision
what is chemistry
study of properties structures and composition of matter
matter state can be interchanged from one to the other depending on
environmental temperature
processes that take in heat
endothermic
processes that take out heat
exothermic
properties of solids
definite mass shape and volume
cannot be compressed
they do not flow
properties of liquids
have definite mass volume
indefinite shape
not easily compressed
they easily flow
properties of gases
definite mass
indefinite volume and shape
easily compressed
easily flow
define pure substances
this is a substance made up of only one component eg distilled water
define a mixture
a substance that is made up of two or more substances in which the components making up the mixture retain both their chemical and physical properties eg sand and water
define a drug
a substance that is natural or manufactured that when taken in can alter the normal functions of the body
define medicine
any drug that is taken to cure a specific disease
state two types of medicines
over the counter drugs
prescribed drugs
define over the counter drugs
drugs that can be accessed or bought without need of a prescription from a qualified doctor
define prescribed drugs
this are drugs which are accessed and used by use of a prescription from a qualified doctor
define prescription
this is a written instruction on the type of drug and how it should be used
define dose/dosage
this is the amt of medicine that is prescribed by a medical doctor to be used for a period of time
roles of chem to the society
manufacture of:
drugs to fight diseases
fertilizers for food production to fight hunger
cheap alternative fabrics such as nylon plastics for roofing packaging and domestic use
detergents
importance of chem
it is a career subject
helps and assists in manufacture of products that ease our day to day life
impacts skills and knowledge in various areas
we learn about various chemicals and how they manufacture goods
provides intellectual fulfilment and an interest for further learning
branches of chemistry
analytical chemistry
physical chemistry
organic chemistry
*inorganic chemistry
reasons for using glass
its easier to clean
transparent hence one is able to make clear observation
does not react to chemicals or other reagents
withstands high temperatures when heating substancs
chimney
is a metallic cylinder where laboratory gases mix with air ignited at the top producing a flame
collar
a metallic ring having the same diameter as the chimney .it opens and closes the air hole regulating the amt of air entering the chimney
base
it is a flat metallic part that provides a steady support for the bunsen burner
jet
it is a tiny metallic part with a hole that allows lab gases to get into the chimney
gas inlet
it is an external connector that allow gases from gas cylinders to get into the bunsen burner
air hole
it is an opening at the end of the chimney that allows air to mix with the gases
how to light a bunsen burner
connect the bunsen burner to the external source of the gas by using a rubber tubing
ensure the air hole is closed
strike a match stick and place it at the top of the chimney
open the gas tap and the gases ignite to produce a flame
luminous flame
bright yellow in colour
has four zones
produces a lot of light
produces soot
it is less hot
it is large and wavy
burns quietly
non luminous
pale blue in colour
has three zones
does not produce soot
produce less light hence less visible
it is hotter
it is small and steady
burns producing noise
comparison
sooty-not sooty
very hot-fairly hot
it is long and wavy-short and steady
has four zones-has three zones
bright yellow in colour-pale blue in colour
