Date post: | 20-Dec-2015 |
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Types of Chemical ReactionsTypes of Chemical Reactions
1) Oxidation-Reduction (Redox)
2) Combination
3) Decomposition
4) Replacement
5) Ion Exchange
Ion Exchange Reaction – ions of one compound
react with ions of another compound to form:
(1) a solid (precipitate) or
FeCl3 + 3 NaOH → Fe(OH)3 + 3 NaCl
(2) a gas or (3) water
CaCO3 + 2 HCl → CaCl2 + CO2 ↑ + H2O
By definition: 1 atom 12C “weighs” 12 u
On this scale
1H = 1.008 u
16O = 16.00 u
Atomic mass ≡ mass of an atom in atomic mass units (u)
Micro Worldatoms & molecules
Macro World(grams)
Natural lithium is:
7.42% 6Li (6.015 u)
92.58% 7Li (7.016 u)
(7.42 · 6.015) + (92.58 · 7.016)100 = 6.941 u
Average atomic mass of lithium:
mole - the amount of a substance that contains as many particles as there
are atoms in exactly 12.00 grams of 12C
1 mol = NA = 6.02 x 1023
Avogadro’s number (NA)
UNITSUNITS
Molar mass - the mass of 1 mole of in gramseggsshoes
marblesatoms
1 mole 12C atoms = 6.022 x 1023 atoms = 12.00 g
1 12C atom = 12.00 u
1 mole 12C atoms = 12.00 g 12C
1 mole lithium atoms = 6.941 g of Li
For any element
atomic mass (u) = molar mass (grams)
1111
Molecular mass (or molecular weight) - the sum ofthe atomic masses (in u) in a molecule.
SO2
1S 32.07 u
2O + 2 x 16.00 u SO2 64.07 u
For any molecule
molecular mass (u) = molar mass (grams)
1 molecule SO2 = 64.07 u
1 mole SO2 = 64.07 g SO2