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

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