1. Concentration& Metrology practical pharmacololgyBy
Dr.ABEER MANSOUR

2. CONTENT Concentration Molarity Mole fraction Molality Metrology
The Metric System
 The Apothecary System
Converting Weights and Measures

3. Concentration
Solvent Solute

4. DEFINITIONS
Concentration: is amount of substance in a given quantity of a solution

5. DEFINITIONS
Molar concentration(Molarity)as the amount of a constituent (in moles) divided by the volume of the mixture. 
mass

6. DEFINITIONS
Molality: defined as the amount of a constituent (in moles) divided by the mass of the solvent
 Mole fraction: the amount of a constituent divided by the total amount of all constituents in a mixture.
Mass concentration: The mass concentration is defined as the mass of a constituent m divided by the volume of the mixture V
Number concentration
The number concentration C is defined as the number of entities of a constituent N in a mixture divided by the volume of the mixture

7. Volume concentration:The volume concentration (do not confuse with volume fraction[ is defined as the volume of a constituent divided by the volume of the mixture

8. Concentration of Solution
Molarity
Parts ratio
Mole Fraction
Molality
Moles of solute
Liter of solution
Mol L
(M) = =
amount of solute (g or ml)
amount of solution (g or ml) =
(102) or (106) or (109)
(c)
Moles of solute
Total moles of solution =
(m)
Mass of solvent
Moles of solute =

9. Molarity Example Problem 1
NaCl
12.6 g of NaCl are dissolved in water making 344mL of solution. Calculate the molar concentration.

10. Molarity Example Problem 2
NaCl
How many moles of NaCl are contained in 250.mL of solution with a concentration of 1.25 M?
Volume x concentration = moles solute

11. Molarity Example Problem 3
NaCl
What volume of solution will contain 15 g of NaCl if the solution concentration is 0.75 M?
moles solute ÷ concentration = volume solution

12. Mass and volume units must match.
% Concentration
% (w/w) =
% (w/v) =
% (v/v) =
Mass and volume units must match.
(g & mL) or (Kg & L)

13. % Concentration Example Problem 1 Example Problem 2 % (w/v) =
(Solid in a Liquid)
What is the concentration in %w/v of a solution containing 39.2 g of potassium nitrate in 177 mL of solution?
% (w/v) =
Example Problem 2
(Liquid in a Liquid)
What is the concentration in %v/v of a solution containing 3.2 L of ethanol in 6.5 L of solution?
% (v/v) =

14. What volume of 1.85 %w/v solution is needed to
% Concentration
Example Problem 3
What volume of 1.85 %w/v solution is needed to
provide 5.7 g of solute?
% (w/v) =
We know:
We want to get:
g solute ÷ concentration = volume solution

15. Parts per million/billion (ppm & ppb)or
= ppm or
= ppb
AND
For very low concentrations:
= ppt
parts per trillion
Mass and volume units must match.
(g & mL) or (Kg & L)

16. ppm & ppb or Example Problem 1
An Olympic sized swimming pool contains 2,500,000 L of water. If 1 tsp of salt (NaCl) is dissolved in the pool, what is the concentration in ppm?
1 teaspoon = 6.75 g NaCl or

17. ppm & ppb or Example Problem 2
An Olympic sized swimming pool contains 2,500,000 L of water. If 1 tsp of salt (NaCl) is dissolved in the pool, what is the concentration in ppb?
1 teaspoon = 6.75 g NaCl or

18. Mole Fraction c A = c B = Mole Fraction (c) moles of A
sum of moles of all components A B +
c B =
moles of B
sum of moles of all components B A +
Since A + B make up the entire mixture, their mole fractions will add up to one.

19. Mole Fraction Example Problem 1
In our glass of iced tea, we have added 3 tbsp of sugar (C12H22O11). The volume of the tea (water) is 325 mL. What is the mole fraction of the sugar in the tea solution?
(1 tbsp sugar ≈ 25 g)
First, we find the moles of both the solute and the solvent.
Next, we substitute the moles of both into the mole fraction equation.

20. Mole Fraction Example Problem 2
Air is about 78% N2, 21% O2, and 0.90% Ar.
What is the mole fraction of each gas?
First, we find the moles of each gas. We assume 100. grams total and change each % into grams.
Next, we substitute the moles of each into the mole fraction equation.

21. Metrology
Metrology:  called the arithmetic of pharmacy, is the science of weights and measures and its application to drugs, their dosage, preparation, compounding, and dispensing.

22. Metric System
The Metric System  The metric system is the official system of weights and measures used by Pharmacy Departments for weighing and calculating pharmaceutical preparations. The metric system is becoming the accepted system throughout the world. primarily with the divisions of weight, volume, and linear measurement of the metric system. Each of these divisions has a primary or basic unit and is listed below:
. Basic unit of weight is the gram, abbreviated "g"  · Basic unit of volume is the liter, abbreviated "l"  · Basic linear unit is the meter, abbreviated "m"

23. The Apothecary System
called the arithmetic of pharmacy, is the science of weights and measures and its application to drugs, their dosage, preparation, compounding, and dispensing .It is vital for Hospital to understand the principles and applications of metrology in pharmacy. Errors in this area endanger the health-even the life-of the patient.  
Although fast becoming obsolete, the apothecary system for weighing and calculating pharmaceutical preparations is still used and must be taken into consideration. It has two divisions of measurement: weight and volume. In this system, the basic unit of weight is the grain (abbreviated "gr"), and the basic unit of volume is the minim (abbreviated "m").
The Avoirdupois System  The avoirdupois system is a system used in the United States for ordinary commodities. The basic units of the avoirdupois system are dram ( grains), ounce (16 drams), and pound (16 ounces).

25. Converting Weights and Measures
Occasionally, there are times when it will be necessary to convert weights and measures from one system to another, either metric to apothecary or vice versa. Since patients hardly be expected to be familiar with either system, always translate the dosage directions on the prescription into a household equivalent that they can understand