1. Hawler Medical University Department of Pharmaceutical chemistry
Presented by pharmacist Omar Abdulrahman M.Sc. Pharmaceutical chemistry
Hawler Medical University
College of Pharmacy
Department of Pharmaceutical chemistry

2. Medicinal Chemistry Definition
Definition: Medicinal chemistry, also known as Pharmaceutical chemistry is an interdisciplinary science concerned with the design, development and synthesis of pharmaceutical or bio-active molecules. The discipline combines expertise from chemistry and pharmacology to identify, develop and synthesise chemical agents that have a therapeutic use and to evaluate the properties of existing drugs.

3. Mass and Moles of a Substance
Chemistry requires a method for determining the numbers of molecules in a given mass of a substance.
The molecular weight of a substance is the sum of the atomic weights of all the atoms in a molecule of the substance.

4. Mass and Moles of a Substance
The Mole Concept:
A mole is defined as the quantity of a given substance that contains as many molecules or formula units as the number of atoms in exactly 12 grams of carbon–12.
1-octanol
Mercury(II) Iodide
The number of atoms in a 12-gram sample of carbon–12 is called Avogadro’s number (to which we give the symbol Na). The value of Avogadro’s number is 6.02 x 1023.
Sulfur
Methanol

5. Mass and Moles of a Substance
Mole calculations:
Suppose we have grams of iron (Fe). The atomic weight of iron is g/mol. How many moles of iron does this represent?

6. Mass and Moles of a Substance
Mole calculations:
suppose we have 5.75 moles of magnesium (atomic wt. = 24.3 g/mol). What is its mass?
Or 1.40 x 102 grams of Mg

7. Concentration of Solutions
Molarity (M), or molar concentration, is a measure of the concentration of a solute in a solution, or of any chemical species, in terms of amount of substance in a given volume. is defined as the number of moles of solute per liter of solution.
Other common
rearrangements:

8. Concentration of Solutions
Normality Definition
Normality is a measure of concentration equal to the gram equivalent weight per liter of solution. Gram equivalent weight is the measure of the reactive capacity of a molecule. The solute's role in the reaction determines the solution's normality. Normality is also known as the equivalent concentration of a solution.
N = molarity x equivalents

9. equiv.wt of H2SO4 = M.wt H2SO4 / 2 = 98/2 = 49 g/equiv
equiv.wt of an acid = M.wt / no. of replaceable H+
Example:
equiv.wt of H2SO4 = M.wt H2SO4 / 2 = 98/2 = 49 g/equiv
equiv.wt of H3PO4= M.wt H3PO4 / 3 = g/equiv
Example Problem
Find the normality of 0.1 M H2SO4 (sulfuric acid) for the reaction:
H2SO4 + 2 NaOH → Na2SO4 + 2 H2O
According to the equation, 2 moles of H+ ions (2 equivalents) from sulfuric acid react with sodium hydroxide (NaOH) to form sodium sulfate (Na2SO4) and water. Using the equation:
N = molarity x equivalents
N = 0.1 x N = 0.2 N

10. Potential Issues Using N for Concentration
Although normality is a useful unit of concentration, it can't be used for all situations because its value depends on an equivalence factor that can change based on the type of chemical reaction of interest. As an example, a solution of magnesium chloride (MgCl2) may be 1 N for the Mg2+ ion, yet 2 N for the Cl- ion. While N is a good unit to know, it's not used as much as molarity or molality in actual labwork.

11. How would you prepare 60.0 mL of 0.2 M
HNO3 from a stock solution of 4.00 M HNO3?
M1V1 = M2V2
V1 =
M2V2 M1 =
0.200 x 0.06
4.00
=3 mL
3 mL of acid
+57 mL of water
=60 mL of solution

12. Another Dilution Problem
If 32 mL stock solution of 6.5 M H2SO4 is diluted to a volume of 500 mL
What would be the resulting concentration?
M1*V1 = M2*V2
(6.5M) * (32 mL) = M2 * mL
6.5 M * 32 mL
M2 =
500 mL
M2 = M

13. Example : Prepare 0.1 M of NaCl in 250 ml of Water ?
Wt= M x M.wt. x V(ml) / 1000
= 0.1 x x 250 / 1000
= g

14. Molarity(M) of acid= [sp.gr x % x 1000] / M.wt.
Example: Calculate the Molarity(M) of HNO3
M.wt=63g/mole , sp.gr =1.42 , %w/w= Molarity(M) of HNO3 = (1.42x0.70x1000)/63=16 M.

15. Example:
Calculate the volume required to prepare 100 ml of HCl 6.0M .
37%w/w, sp.gr =1.18 and M.wt HCl = 36.5
MHCl=(1.18 x 0.37 x 1000) / 36.5 = 12 mol/l=12M
Vconc. x Mconc. =Vdil. xMdil Vconc x 12 =100 x 6.00
Vconc = 50 ml

16. Theoretical and Percentage of Yield
The theoretical yield of product is the maximum amount of product that can be obtained from given amounts of reactants.
The percentage yield is the actual yield (experimentally determined)