mass
'no magic to the mole'
amount
molar mass
concentration
solution volume
gas volume
molar gas volume
Avogadro
constant, L
number of
entities, N
Now try the following question.
C6. MOLAR MASS FOR KNOWN SUBSTANCES FROM TABLES OF DATA
The molar mass of a known substance is easily obtained from its chemical formula using relative atomic mass data listed routinely in a Periodic Table of Chemical Elements. The procedure is similar to obtaining values for relative molecular mass that you may already have carried out. But, remember, molar values take the units g / mol.
6.1 MOLAR MASSES FOR ELEMENTS OF KNOWN FORMULA
e.g., M (H) = {A (H)} g/mol = 1.01 g/mol
r
take numerical values with NO UNITS since they are all ratios,
e.g.,
N.B. A , relative atomic mass, & M , relative molecular mass / relative formula mass
r
r
A (U) = 238 &
r
r
M (P ) = 124
4
Molar mass is a physical quantity; its values must have units: g / mol
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