Laboratory Mathematics

Any substance dissolved in liquid:

The liquid in which it is dissolved:

Solute

Solvent

It is the biological solute

Analyte

Expressed as the amount of solute per 100 total units

Percent Solution

Most commonly used percent solution in the clinical laboratory. # of grams of solute in 100 mL of solution

Weight per volumme

Equation for W/V

% of solution*total volume / 100 = grams of solute

Used for liquid solutes, gives the mililiters of solute in 100 mL of solution

Volume per volume

Equation for V/V

% of solution*total volume desired = mL of solute

Refers to the number of grams of  solute per 100g of solution

W/W

W/W equation

%of solution*total g desired / 100 = grams of solute

Depends on volume so it is affected by temp and pressure

Molarity

Molarity Equation:

grams of solute / grams mw*vol of solution in L = molarity

Molles = weight in grams / gmw

It is not affected by volume thus, not affected by temperature and pressure

Molality

Molality equation

grams of solute / gmw*total weight in kg

It is the least used, and is often for acid-base balance, calculation, chemical titration. It is the number of equivalent weight of solute per liter of solution

Normality

Normality Equation:

Equivalent weight equation: 

g of solute / Eq.*total volume in L

MW / Valence

Relationship between Normality and Molarity

Normality is equal or greater than Molarity

Molarity = Normality / Valence

Miliequivalent equation

mg/dl*10 * valence / MW

Milimoles equation

mg/dl*10 / mw