chapter 5 - quantifying chemistry Flashcards
what is carbon-12 used for?
it is used as the standard for comparing relative isotopic masses as it is stable and abundant
what is the mass spectrometer
helps to determine the relative isotopic masses of the different isotopes of an element and abundance
what does the mass spectrometer tell us
- the number of isotopes in a given sample of an element
- the relative isotopic mass of each isotope
- the percentage abundance of the isotopes
how to calculate the relative atomic mass (Ar)
(RIM of isotope times aunbdance) + …….. over 100
define relative atomic mass - Ar
the mean mass of the naturally occurring mixture of the isotopes of an element on the relative atomic mass scale,
by comparing masses against the mass of carbon -12
define relative isotopic mass - RIM
the mass of an individual isotope of an element on the relative atomic mass, by comparing masses against the mass of carbon-12
what is n
= the number of moles (6.02 times 10^23)
what is m
the mass of the sample
what is M
the molar mass of the sample
what is the mole
6.02 times 10^23
what is the unit for M
g/mol = grams per mole
what is the unit for m
g = grams
how do you find the number of moles
n = m/M
how do you find the m (mass)
m = nM
how do you find the M (molar mass)
M = m/n
number of particles - to - moles
divide by Na
moles - to - number of particles
multiply by Na
what is Na
Avogadro’s number = 6.02 times 10^23
define empirical formula
the E.F shows the simplest numerical ratio in which atoms are combined
define molecular formula
the M.F is the actual number of atoms of each element in a molecule of a substance
fine percentage composition
list of percentages by mass of the elements in a compound
