C1 Flashcards
What is an atom
Single particle
Everything made of them
What is an element
Substance made of one type of atom
What is a compound
Substance made of different types of atoms chemically bonded together
What goes on the left of a chemical equation
Reactants
What goes on the right of a chemical equation
Products
What is a balanced chemical equation
Same amount of each atom on both sides
Law of conservation of mass
Total mass of products equals total mass of reactants
Aqueous solution
Substance dissolved in water
Filtration
Used to separate insoluble substance from a solvent
Filter paper, funnel, beaker
Crystallisation
Separated solute form solvent
Heat solution until small crystals appear
Leave to evaporate fully
Simple distillation
Captures gas given off from crystallisation
Solution heated a boiled
Solvent evaporates
Vapour enters condenser
Vapour condenses back to liquid
Collected in a beaker
Fractional distillation
Separates miscible liquids
Add fractioning column to simple distillation
- hotter at bottom and cooler at top
Liquid with lower bpt will travel higher and enter condenser
Liquid with higher bpt will condense near bottom of column and go back down
Paper chromatography
Used to separate substances in mixtures
Dab spots of mixture near bottom of paper and draw line in pencil
Paper is placed in a solvent (not touching the mixture)
Solvent soaks up the paper
The more soluble a substance is, the further it will travel
John Dalton
First
Atoms are small, hard spheres
Each element had its own atom
Atoms couldn’t be split
J.J. Thompson
Discovered the electron
Plum pudding model
- tiny negatively charged electrons embedded in positive cloud
Rutherford
Geiger and Marsden fired alpha particles (dense and positive) at thin piece of gold foil
Expected them to go straight through the gold atoms
Some deflected off course and some reflected backwards
Positive charge must be concentrated in centre of atom
Electrons must be orbiting this nucleus
Neil Bohr
Electrons must be orbiting the nucleus at set distances in shells
James Chadwick
Scientist knew there must be a second subatomic particle in the nucleus to explain the extra mass
Must have same mass as protons but no charge
James Chadwick discovered them
Subatomic particles relative charge
Electron = -1
Neutron = 0
Proton = 1
Subatomic particles relative mass
Electron = 0
Proton = 1
Neutron = 1
Atomic number
Number of protons
Mass number
Number of protons + neutrons
Ion
When an atom gains or looses electrons
A charged atom
Isotope
Atoms of the same element with different numbers of neutrons
Sometimes unstable
Some have different physical properties
