slides on elements compound and mixtures class 8

1. Elements,
Compounds
and Mixtures
Anusha mishra

2. Elements
Elements are basic substances which
cannot be further broken down into
simpler substances by chemical
methods.*115 elements (91 occur
naturally, 24 made artificially by
scientists)Classified by properties (ie.
metal or nonmetal)
Atom - Smallest part of an element that
can exist as a stable entity. Represented
by symbols.
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3. Compounds are pure substances which
are formed when 2 or more elements
chemically combine.
•Compounds cannot be separated by
physical means - only by chemical
reactions.
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4. Mixtures
A mixture contains more than
one substance (elements
and/or compounds.)
•Mixtures can be physically
separated.
•Composition is mixed and
properties are those of the
individual elements
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5. Separating Mixtures
•If a solid substance is soluble it
will dissolve when added to a
liquid and form a solution. The
liquid is called the solvent and
the dissolved solid is called the
solute.
•If a solid substance is insoluble
it does not dissolve in liquid.
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6. Separating
Solid/Liquid
Mixtures
Crystallizing
Centrifuging & Simple
Distillation
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Filtration
Decantation
Evaporation

7. Pour mixture into a
funnel containing
filter paper. The
residue (solid) is
trapped in the filter
paper while the
filtrate (liquid)
passes through it
into a collection
container below.
Filtering

8. Slowly pour the
mixture into a
collection container
allowing the filtrate
to run.
Decanting

9. Evaporation is good if a
solid has been
dissolved in a solvent
and can't be filtered or
decantation .Slowly
heat the mixture until
the solvent has been
completely evaporate
and leaves the solid
behind.
Evaporating

10. This is a process that
uses the sun to
evaporate salt from
brine. Brine is a
supersaturated
solution which contains
as much salt as it can
dissolve. When the
water is evaporated
the salt crystallizes.
Crystallisation
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11. A separating funnel
is used to separate
liquids that are
immiscible (liquids
that don't mix). The
lower layer can be
released by
opening the tap.
Simple
Distillation

12. Thank you
Anusha Mishra