stoichiometry

formulas

the piramids

n = m : M

n - number of moles

m - mass [grams]

M - molar mass (from periodic table)

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N = Nan → n = N : NA

N - number of molecules

NA - avogadros number ($6,022 * 10^23$)

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n = V : Vm

V - volume - mass : density

Vm - molar volume (a volume occupied by 1 mole) - in stp its ^^22,7^^dm^3/mol, in rtp its ^^24^^ dm^3/mol

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d = m : V

d = M : Vm

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given temp and pressure

standard temperature and pressure (^^STP^^)

T = 0*C, 273K

Vm = 22,7dm^3/mol

P = 100kPa

room temperature and pressure ($RTP$)

T = 25*C, 298K

Vm = 24dm^3/mol

P = 100kPa

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empirical and molecular formula

empirical formula

1. if % - change into grams
2. grams into moles (m : M)
3. divide everything you got by the smallest of the values
4. round them up to whole numbers
5. now put these numbers as the little ones
6. done :grinning:

molecular formula

1. find the M (molar mass) of the empirical formula
2. divide the larger M by the smaller M
3. divide the little ones in empirical formula by the number that you get
4. and these are the new little ones
5. done :grinning:

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