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Chemistry - Module 2 - The Atom - Part 2 - Coggle Diagram
Chemistry - Module 2 - The Atom - Part 2
relative mass and mass spectrometry
definitions
relative atomic mass, Ar, is weighted mean mass relative to 1/12 mass of carbon-12
relative isotopic mass compares an isotope to 1/12 of carbon-12
relative molecular/formula mass, Mr, similar for molecules/formula units
mass spectrometer outputs
mass spectrum plots abundance (y) versus m/z (x)
since ions are mostly +1, m/z approximates relative isotopic mass
typical process: ionisation, acceleration, separation, detection
the mole and molar quantities
Avogadro constant and mole
one mole contains 6.02 x 10^23 particles
number of moles = number of particles / Avogadro constant
molar mass and calculations
molar mass. Mr, equals relative atomic/molecular mass with units g mol-1
number of moles = mass / molar mass
gas volumes and ideal gas equation
molar gas volume at room temperature = 24 dm^3 mol^-1
for other conditions use pV = nRT; with T in Kelvin and R is the gas constant
empirical and molecular formulae
empirical formula
smallest whole-number ratio of atoms of each element in a compound
determined by converting masses to moles and dividing by the smallest mole value
molecular formula
actual number of atoms per molecule
found by dividing molar mass by empirical unit mass and scaling empirical formula accordingly
chemical equations and ionic equations
balancing chemical equations
must have same number of each atom on both sides; adjust by placing coefficients in front of formulas
ionic equations
write full balanced equation with states, split soluble ionic species into ions, remove spectator ions, ensure charge balance