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.
Distillation is …
used to separate liquids with different boiling points to get a pure substance out of a mixture.
Solute
A solid that dissolves.
If a solute doesn’t dissolve in a solvent, then it is …
Insoluble.
If a solute does dissolve in a solvent, then it is
…
Soluble.
What is boiling/evaporation?
A liquid turning into a gas.
Solvent is …
A liquid that does the dissolving
What is condensation?
It is a gas turning into a liquid.
What is a solution?
It is formed when a solute completely dissolves in a solvent.
Filtrate is …
what filters through the filter paper into the conical flask.
Residue is …
what is left in the filter paper after filtration.
How does paper chromatography work?
It works by being able to separate substances with different solubilities, you can see the different substances in a mixture.
What are 2 things you have to do to make sure
