Nov topic test Flashcards
relative atomic mass
weighted mean mass of an atom of an element relative to 1/12 mass of an atom of carbon 12
rel isotopic mass
mass of an isotope relative to 1/12 mass of an atom of carbon 12
isotopes
same number of protons/electrons diff number of neutrons
react in the same way
may have diff phys properties- higher atomic mass- higher M/B point and higher density
ion
charged atom- proton and electron number is not the same
cations ( pos) - have more protons than electrons
anions ( neg)- have more electrons than protons
mass defect
small amount of mass lost due to strong nuclear force holding together protons/ neutrons
mass spectrometer
find % abundance of isotopes
mass spec method
atoms placed in MS vapourised and ionised to form positive ions
ions accelerated ( heavier= slower) - separates different isotopes
ions detected as mass: charge ratio
- greater abundance= greater signal
- ions with 1+ charge - ratio equivalent to RIM
avogadro constant
6.02 x10^23
number of particles in one mole of carbon 12
molecular formula
number of atoms of each element in a molecule
empirical formula
simplest whole number ratio of atoms of each element in a compound
standard solution
sol. of known concentration
exact mass of solute in exact volume
assumptions for ideal gas
no IM forces
particles of negligible size
elastic collisions
random motion
ideal gas eq
pV= nRT
p- Pa
V- dm3
n= moles
R= 8.314
T- K (+ 273)
theoretical yield
max possible product
may not achieve if: reaction didnt go to completion
- side reactions
- product may be lost in purification processes
atom economy
Mr desired product/ Mr all reactants
