F321 Chemistry Notes
- Created by: Sanchia
- Created on: 04-05-12 21:15
F321
Isotopes - Atoms of the same element - same number of protons and electrons - same chemical reactions (speed varies) Physical properties such as melting point and density varies
(Relative atomic mass x Abundance) + (repeat) / 100
+ Protons relative mass 1
Neutrons relative mass 1
- Electrons 1/2000th the mass of a proton
Relative Atomic Mass is the weighted mean mass of an atom of an element compared with 1/12 of the mass of an atom of Carbon 12
Relative Isotopic Mass is the mass of an atom of an isotope compared with1/12 of the mass of an atom of Carbon 12
Equations
Mole the amount of any substance containing as many particles as there are carbon atoms in exactly 12g of the carbon-12 isotope
Number of moles = Mass / Atomic Molecular Mass
Empirical Formula simplest whole number ratio of atoms of each element present in a compound
Mass / Atomic Mass = Moles / smallest number = Ratio
Molar mass Number of atoms of each element in a molecule
Molecular Mass / Empirical = Number of molecules
Molecular Formula Number of atoms of each element in a molecule
Avogadro's Law for any gas the number of particles is always the same
Volume of gas (cm3) / 24 (24000) = Number of moles
Concentration x Volume [cm3/1000] = Number of moles
1 Mole is equivalent to 6.023 x 10^23 (Avogadro's number) units of any substance.
Acids
Acid + Metal > Salt + Hydrogen
Acid + Metal Oxide > Salt + Water
Acid + Carbonate > Salt + Water + Carbon dioxide
Neutralisation H+(aq) + OH-(aq) > H2O (l)
Acid + Alkali > Salt + Water
Salt - The H+ ion in an acid has been replaced by a metal ion
Acids - HCl, H2SO4, HNO3 Alkalis (soluble base) - metal oxides, metal hydroxides, ammonia Finding x in hydrated solutions
Mass of solution - mass after heated - Use empirical formula method
Redox / Disproportionation
Oxidation The number of electrons an element uses to bond to other atoms
Uncombined elements - Ca, He, O2, Cl2 - Oxidation number of 0
Combined oxygen - H2O, CO2 - Oxidation number of -2
Combined hydrogen - HCl - Oxidation number = +1
Ions Li+ = +1, Ca2+ = +2, Cl- = -1 Oxidation number = depends on charge of ion
Metals generally lose electrons and have an increase in oxidation number to form positive ions - oxidised Non-metals generally gain electrons and have a decrease in oxidation number to form negative ions - reduced
Oxidation Involves Loss Reduction Involves Gain of electrons
Oxidation is an increase in oxidation number
Reduction is a decrease in oxidation number
Electron Structure
An atomic orbital is a space within an atom that can hold up to two electrons with an opposite spin S-Orbital 2e- P-Orbital 6e- D-Orbital 10 e- F-Orbital 14 e-
Degenerate Orbitals (P, D, F)
The first ionisation energy of an element is the…
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