b. A millimole has the same numerical value as one gram molecular weight,
however, it is expressed in mg/mmol.
c. To convert mol/L to mmol/L and vice versa, multiply the concentration by the
conversion factor 1000 mmol/1 mol as appropriate.
Example: (0.25 mol/L)(1000 mmol/1 mol) = 250 mmol/L
d. To convert mmol/L to mol/L, multiply mmol/L by (1 mol/1000 mmol).
Example: (2000 mmol/L)(1 mol/1000 mmol) = 2.000 mol/L
e. Use the following formula to solve millimole/liter problems:
(1)
Formula. mg = (mmol/L)(mg/mmol)(L)
(2)
Example. How much NaCl is needed to make 250 mL of a 300 mmol/L
solution?
Solution. Read the problem carefully and select the formula that
generates the desired quantity.
mg = (mmol/L)(mg/mmol)(L)
Determine the millimolar weight of the compound.
NaCl
Na
23.0
Cl + 35.5
58.5 mg/mmol
Substitute the given information.
mg = (300 mmol/L)(58.5 mg/mmol)(250 mL)
Make any necessary conversions.
mg = (300 mmol/L)(58.5 mg/mmol)(0.250 L)
Evaluate the expression to determine the unknown quantity.
mg = 4390 mg
MD0837
3-7