Analytical Chemistry PDF - Mansoura National University

# Analytical Chemistry ## Qualitative and Quantitative Analyses * **Qualitative Analysis**: Identification of analytes (Yes or No) by physical property (color, taste, solubility) * **Quantitative Analysis**: Determine the concentration (amount of substance) (Determination or Estimation or Assay)....

# Analytical Chemistry ## Qualitative and Quantitative Analyses * **Qualitative Analysis**: Identification of analytes (Yes or No) by physical property (color, taste, solubility) * **Quantitative Analysis**: Determine the concentration (amount of substance) (Determination or Estimation or Assay). ## Branches of Analytical Chemistry ### Physical Chemistry * Chemical Kinetics ### Pharmaceutical Analytical Chemistry ### General Inorganic Chemistry * Chemical Equilibrium * Mole Concept ### Quantitative Volumetric Analysis * Acid-base titration * Precipitation titration # Mansoura National University ## Pharm D-Clinical Pharmacy Program ### Level 1 ### Pharm. Anal. Chem. 1 (PC 101) ## What is Chemistry? The branch of science that deals with chemicals. Chemicals include all the day-to-day things you touch, see, and smell. They are everywhere (except in the vacuum). ## What are Chemicals Composed of? Chemicals are composed of different substances (substance means chemical material of which an object is composed e.g. ice is composed of substance water, or chemical material water). Despite the benefits of chemistry, we have to be careful in dealing with chemicals. Many chemicals are toxic, others are potential cancer producers, and should be handled with control. ### Solution Terminology * **Solvent**: A substance that dissolves other materials to form a solution. * **Solute**: A substance that dissolves in a solvent. * **Solution**: A homogenous mixture of one or more solutes dissolved in a solvent. * **Concentrated Solution**: Has a relatively large proportion of solute to solvent. * **Diluted Solution**: Has a relatively smaller proportion of solute to solvent. # Mole Concept * Molecules and atoms are extremely small objects - both in size and mass. * The mole is a standard scientific unit for measuring quantities of very small entities such as atoms or molecules. * 1 Mole = $6.022 × 10^{23}$; Avogadro's Number (Atoms/Molecules/...). * 3 Moles = $3 × 6.022 × 10^{23}$. * It is also equal to the formula weight (atomic or molecular) of a substance expressed in grams. ### Note: * **Weight = Mass** * For atoms: It is termed atomic weight or atomic mass. * For molecules: It is termed molecular weight or molecular mass. * **Formula or molecular weight**: The sum of the atomic weights of the atoms that make up a compound (e.g. MW of NaOH = 23 + 16 + 1 = 40 g). # Mansoura National University ## Pharm D-Clinical Pharmacy Program ### Level 1 ### Pharm. Anal. Chem. 1 (PC 101) ## Mole Calculations * **For Atoms**: Mole is gram atomic weight (Atomic weight expressed in grams). Atomic weight of Na is 23 -- 1 mole Na = 23 g = $6.022 × 10^{23}$ atoms. * **For Molecules**: Mole is gram molecular weight (Molecular weight expressed in grams). M.W of NaOH is 40-- 1 mole NaOH = 40 g = $6.022 × 10^{23}$ molecules. * 1 Mole = $6.022 × 10^{23}$ atoms/molecules/particles. * 1 Mole = atomic, molecular, or formula weight in grams. * **Grams** = **Moles** × **Atomic/Molar Mass** * **Moles** = **Grams** ÷ **Atomic/Molar Mass** # B) Electrolytes ## Strong Electrolytes * Substances that are completely dissociated in an aqueous solution. * Their solution can conduct electricity (e.g. NaCl and HCl). * **Examples**: Strong acids, strong bases, salts of strong acid and base. * HCl(aq) + H₂O → Cl(aq) + H₃O+(aq) ## Weak Electrolytes * Substances that dissociate to a small extent in an aqueous solution. * They are weakly conductive to electric current (e.g. acetic acid, water). * **Examples**: * **a)** H₂O ionizes to only $10^{-7}$ M: H₂O(aq) + H₂O → H₃O+(aq) + OH-(aq) * **b)** CH₃COOH ionizes to only 0.42% w/v: CH₃COOH + H₂O → CH₃COO-(aq) + H₃O+(aq) * **c)** NH₄OH and HCN. # Solubility * **Solubility**: Is a measure of how a solute will dissolve in a solvent at a constant temperature. * **Soluble**: Can dissolve in a solvent. * **Insoluble**: Cannot dissolve in a solvent. * Ionic compounds are soluble in polar solvents & have low solubility in nonpolar solvents (e.g. NaCl dissolves in water). # Mansoura National University ## Pharm D-Clinical Pharmacy Program ### Level 1 ### Pharm. Anal. Chem. 1 (PC 101) ## Liquids Dissolving in Liquids * Liquids that are soluble in one another ("mix") are **miscible**. * **"LIKE dissolves LIKE"**: Polar liquids are generally soluble in other polar liquids (e.g. CH₃OH is miscible with water). ## Nonpolar Liquids * Nonpolar liquids are generally soluble in other nonpolar liquids (e.g. CCl₄ and CH₄ are miscible with each other). # Concentrated vs. Dilute Solutions * **Concentrated Solution**: Notice how dark the solution appears. Lots of solute in a small amount of solvent. * **Dilute Solution**: Notice how light the solution appears. Small amount of solute in a large amount of solvent. ## Solution Saturation * **Unsaturated Solution**: A solution that can dissolve a further amount of solute at a particular temperature. * **Saturated Solution**: A solution that cannot dissolve a further amount of solute at a particular temperature. * **Supersaturated Solution**: A solution that contains more amount of solute than required to saturate it at a particular temperature. ### Note: Supersaturated solutions are unstable and release their extra-solid reaching the point of saturation when: * A tiny crystal (seed) of a solid is added, and additional solute crystallizes on this "seed" crystal. * Further cooling of the supersaturated solution. # Mansoura National University ## Pharm D-Clinical Pharmacy Program ### Level 1 ### Pharm. Anal. Chem. 1 (PC 101) ## Unsaturated vs. Saturated vs. Supersaturated Solutions * **Unsaturated Solution**: More solute dissolves; the solution is clear. * **Saturated Solution**: No more solute dissolves; the solution is clear. * **Supersaturated Solution**: Becomes unstable; crystals form. # Electrolyte and Nonelectrolyte Solutions ## A) Nonelectrolytes * Molecular substances have no tendency to dissociate in water. * Their solutions can't conduct electricity (e.g. sugar and ethyl alcohol).