Elements, Compounds and Mixtures Flashcards
What is definition of an Element?
A pure substance in which all of the atoms are identical.
What is the definition of a Compound?
A substance made up of the atoms of 2 or more elements which have been chemically joined together, difficult to separate.
What is the definition of a Mixture?
A substance made up of the atoms of 2 or more elements or compounds not chemically joined together, easy to separate.
What is the definition of an Atom?
Smallest particle of a substance.
What is the definition of a Molecule?
It is 2 or more atoms chemically combined; the atoms can be the from same or different elements.
Simple Distillation
Process of separating 2 liquids of different boiling points or to separate the solvent and solid solute from a solution.
Fractional Distillation
Process to separate liquids with similar boiling points.
Chemical Change
New substance is formed.
Physical Change
No new substance is formed.
Aluminium, Copper and Sulphur are …
Examples of Elements.
Ammonia, Carbon Dioxide and Pure Water are …
Examples of Compounds.
Why are pure substances having fixed boiling, melting points and a mixture not useful?
This is useful because we can tell if a substance is pure or mixed by if when the substance is changing state for a pure substance the temperature won’t change but it will for a mixture.
What are 5 techniques to separate substances?
Filtration, crystallisation, paper chromatography, simple distillation, fractional distillation.
Filtration is …
used to sperate a liquid and an insoluble liquid from a solution.
Evaporation is …
used to crystallise a salt by evaporating off the water or other solvent so you are left with a soluble solid from the solution.
