Introductory Flashcards
What are all substances made up of?
What is an atom?
What is an atoms radius?
All substances are made up of atoms
Atoms are the smallest part of an element that possibly exist.
Atoms have a radius of 0.1nm (1x10 to the power of -10 m)
What is an element?
What is a compound?
How are compounds split apart?
An element is a substance made up of only one type of atom
A compound contains two or more elements chemically fixed in proportions
Compounds are not easily split apart and can only be split apart by a chemical reaction.
What is a molecule?
Molecules are two or more atoms chemically joined together. They can be elements or compounds.
What can be used to tell if a substance is pure?
If the melting point matches the given database…
Usually impure substances will…
The melting point can be used to determine if a substance is pure or not.
a) The range of the melting / boiling point will be very small if the sample is pure.
Generally impure substances will have a lower melting point and higher boiling point compared to pure substances.
Explain filtration
Pieces of insoluble solid are too big to fit through filter paper.
Liquid particles easily flow through filterpaper
Insoluble solid pieces in residue.
Liquids / soluble solids in filtrate
Explain crystallisation
Uses to seperate soluble solids.
Evaporate water from solution on a water bath is gentler then direct heating
Stop heating at point of cyrystallisation
Excess water left on window sill to evaporate
Distillation
Used to separate a mixture of liquids
Liquids heated in the flask until one evaporates into a gas
Gas travels down into condenser where it cools and condenses into a liquid
Pure liquid is then collected
What is a mixture?
A mixture is made up of 2 or more different types of elements or compounds that are not chemically joined together.
What is a pure substance?
A pure substance is made up of just one type of element/ compound
Formulation?
A formulation is a mixture that has been specifically designed to produce a useful product eg paints and medicinial drugs
Distillation equipment
Heat, Flask, Condenser, Cooling water from tap, liquid
