Moles Flashcards
Mole
The most important unit of measurement in chemistry
Name is derived from a Latin word meaning “clump”
Atoms are too small to count individually so they are counted in Moles (clumps)
Avogadro’s Number
6.02 x 10^23
Moles are measured by this number
Representative Particle
The smallest form of a pure substance
Molar Mass
The mass (g) of one mole of a substance
Mole Conversions
1 mol of anything = 6.02 x 10^23 individual particles = molar mass
Percent Composition Formula
part/total = %/100
molar mass of element/molar mass of compound = %/100
molar mass of element/molar mass of compound x100 = %
Hydrates
Hydrated Compound - Ionic crystal with physically trapped water (water is NOT bonded)
Anhydrous Compound - The ionic crystal part of a hydrated compound
Water of Crystallization - The trapped molecules of water
Empirical Formula
Most reduced form of a formula
Molecular Formula
Starts with a nonmetal
Finding the Molecular Formula (true formula)
- Calculate the molar mass of the empirical formula
- Divide the molecular formula’s molar mass (usually given in the problem) by the empirical formula’s molar mass to obtain a whole number
- Multiply the subscripts of the empirical formula by the whole number to get the true formula
Synthesis/Composition
Element + Element –> Compound
A + B —> AB
Combustion
Hydrocarbon + Oxygen –> CO2 + H2O
CxHy + O2 –> CO2 + H2O
Binary Decomposition
AB –> A + B
Metal Chlorate Decomposition
MClO3 –> MCl + O2
M = Metal
Metal Hydroxide Decomposition
MOH –> MO + H2O
M = Metal
