Molecular Formula Flashcards
What does M stand for and what is it?
It is the molar mass (gmol-1) it can be found out using Ar(x)+Ar(b)
(Ar is found on the periodic table)
What does n stand for and how can it be found?
Number of moles(mol)
It can be found using n=m(mass g)/M(gmol-1)
n=N/NA
What does N stand for and how is it found
Number of particles
If we know the mole(n)
N=nxNA
If we know the mass(m)
1.n=m/M
2.N=nxNA
What does m stand for and how can it be found
It is mass(g)
If we know the number of particles (N)
1.n=N/NA
2.m=nxNA
If we know the mole(n)
m=nxNA
what is NA
Advogadros constant (mol-1)
6.02x10^23
Empirical formula
Composition/ mass
Then divide by the smallest answer
Alkane general formula:
CnH2n+2
Alkene general formula:
CnH2n
Alkyne general formula:
CnH2n-2
when asked for the amount of substance
mol
n=N/Na
when asked for the number of molecules
N=nxNa
when asked for the number of atoms
N=(how much elements there are ex. H2O=3)xnxNa
Ar formula
(no. of pt)x(abundance)/100
molecular formula
(gmol-1 that’s given in the question )/molar mass
then use the answer to times the empirical formula with
percentage composition
(how much of the element) x the no. found on pt x 100