Calculations involving millimole per liter solution are very similar to the

calculations involving simple mole per liter solutions.

a. **Example 1**. What is the mmol/L concentration of a 0.25 mol/L NaOH

solution?

Solution. Read the problem carefully and determine the desired unit of

concentration.

mmol/L.

Multiply the given mol/L concentration times the appropriate conversion

factor.

0.25 mol

1000 mmol

--------X ------------ = 250 mmol/L

L

mol

b. **Example 2**. What is the mol/L concentration of a 2000 mmol/L KCl solution?

Solution. Read the problem carefully and determine the desired unit of

concentration.

mol/L.

Multiply the given mmol/L concentration times the appropriate conversion

factor.

2000 mmol

1 mol

------------X ------------ = 2.000 mol/L

L

1000 mmol

c. **Example 3**. How much NaCl is needed to make 250 mL of a 300 mmol/L

solution?

Solution**. **Read the problem carefully and determine the desired quantity.

Milligrams of NaCl.

Determine the millimolar weight of the compound.

NaCl

Na

23.0

Cl

+ 35.5

58.5 mg/mmol

Express the desired volume of solution in liters

1L

250 mL X ---------- = 0.250 L

1000 mL

MD0837

3-8

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