LABORATORY MATHEMATICS Flashcards
Most common type of solution prepared in clinical laboratory
Refers to the number of grams of solute per 100 mL of solution
Weight/Volume (w/v) % solutions
Formula for w/v%
w/v% = [weight of solute (g)/ volume of solution (mL)] x 100
Used when both solute and solvents are liquid
Refers to the amount of solute in mL in 100 mL of solvent
Volume/Volume (v/v)% solutions
Formula of (v/v)%
v/v% = [volume of solute (mL)/ volume of solution (mL)] x 100
Number of grams of solute per 100 grams of solution
Weight/Weight (w/w)% solutions
Formula of w/w%
w/w% = [(mass of solute in g/ mass of solution in g)] x 100
Number of moles of solute per liter of solution
Molarity
Formula of Molarity
M = moles of solute (mol)/ Liters of solution (L)
To prepare a molar solution
Grams of solute = Molarity x GMW of the solute x Volume (L)
To convert %w/v to Molarity
M = %w/v x 10 /GMW
Number of equivalent weight of solute per liter of solution
Often been used in acid-base calculations
Normality = Grams of solute/ EW x Volume (L)
Formula of Equivalent Weight
EW = MW/valence
To prepare a normal solution of Solids
Grams of solute = EW x Normality x Volime (L)
To convert %w/v to Normality (N)
N = %w/v x 10 / EW
Formula of Normality
Normality = Molarity x Valence
Formula of Molarity from Normality
Molarity = Normality
Amount of solute per 1 kilogram of solvent
Expressed in terms of weight/weight or moles per kilogram
Molality
Formula of Molality
Molality = grams of solute/ MW x kg of solvent