Water, Acids-Bases, and Buffer Systems Lecture Notes 2024 PDF

Water, Acids-Bases, and Buffer Systems Caner GEYİK [email protected] 2024  HSF101 - Biochemistry/ 2023 2 Learning Objectives Recognize the structure of water Relate water structure with solubility...

Water, Acids-Bases, and Buffer Systems Caner GEYİK [email protected] 2024  HSF101 - Biochemistry/ 2023 2 Learning Objectives Recognize the structure of water Relate water structure with solubility Calculate concentrations in solutions Defines acids and bases Describes buffers  HSF101 - Biochemistry/ 2023 3 Water  HSF101 - Biochemistry/ 2023 4 Su  HSF101 - Biochemistry/ 2023 5 Water as Universal Solvent Water is the solvent of life. Dissolves and transports compounds in the blood Plays role on the movement of molecules into and throughout cellular compartments Separates charged molecules Dissipates heat Participates in chemical reactions  HSF101 - Biochemistry/ 2023 6 Water as Universal Solvent Water is the solvent of life. Dissolves and transports compounds in the blood Plays role on the movement of molecules into and throughout cellular compartments Separates charged molecules Dissipates heat Participates in chemical reactions  HSF101 - Biochemistry/ 2023 7 Water as Universal Solvent Water is the solvent of life. Dissolves and transports compounds in the blood Plays role on the movement of molecules into and throughout cellular compartments Separates charged molecules Dissipates heat Participates in chemical reactions + -  HSF101 - Biochemistry/ 2023 8 Water as Universal Solvent Water is the solvent of life. Dissolves and transports compounds in the blood Plays role on the movement of molecules into and throughout cellular compartments Separates charged molecules Dissipates heat Participates in chemical reactions  HSF101 - Biochemistry/ 2023 9 Water as Universal Solvent Water is the solvent of life. Dissolves and transports compounds in the blood Plays role on the movement of molecules into and throughout cellular compartments Separates charged molecules Dissipates heat Participates in chemical reactions  HSF101 - Biochemistry/ 2023 10 Structure of Water Covalent bond (Intramolecular bond)  HSF101 - Biochemistry/ 2023 11 Structure of Water Electronegativity: Power to attract electrons Oxygen is more electronegative than hydrogen  HSF101 - Biochemistry/ 2023 12 Structure of Water δ - δ + δ + Dipolar molecule  HSF101 - Biochemistry/ 2023 13 Structure of Water  HSF101 - Biochemistry/ 2023 14 Structure of Water  HSF101 - Biochemistry/ 2023 15 Structure of Water Hydrogen bond (Intermolecular bond)  HSF101 - Biochemistry/ 2023 16 Solubility The dipolar nature is responsible for the role of water as a solvent. Water is often called the universal solvent because it dissolves so many types of substances. Many ionic substances dissolve in water, the negative ends of the water molecules attracts the cations (positively charged ions) the positive ends of the water molecules attract the anions - (negatively charged ions) +  HSF101 - Biochemistry/ 2023 17 Solubility NaCl + Cation: Na+ Anion: Cl- + - - Polar molecules can interact with water = Hydrophilic  HSF101 - Biochemistry/ 2023 18 Solubility  HSF101 - Biochemistry/ 2023 19 Solubility  HSF101 - Biochemistry/ 2023 20 Solubility  HSF101 - Biochemistry/ 2023 21 Solubility  HSF101 - Biochemistry/ 2023 22 Solubility Non-polar molecules can’t interact with water = Hydrophobic  HSF101 - Biochemistry/ 2023 23 Solubility Polar side Non-polar side Amphiphilic or Amphiphatic  HSF101 - Biochemistry/ 2023 24 Solubility  HSF101 - Biochemistry/ 2023 25 Solubility  HSF101 - Biochemistry/ 2023 26 Membrane Formation  HSF101 - Biochemistry/ 2023 27 Solutions Homogenous mixtures of two or more substances Major component: Solvent Minor component: Solute 1st component 2nd component Solution Example Gas Gas Gas Air Gas Liquid Liquid CO2 in H2O Gas Solid Solid H in Palladium Liquid Liquid Liquid EtOH in H2O Solid Liquid Liquid NaCl in H2O Solid Solid Solid Steel (Fe + C)  HSF101 - Biochemistry/ 2023 28 Factors Affecting Solubility Solubility: Ability of a substanceto dissolve in a solvent Type of solute and solvent Temperature Pressure Common Ion Effect  HSF101 - Biochemistry/ 2023 29 Factors Affecting Dissolving Speed Speed: Time needed for dissolving Temperature Particle size Mixing  HSF101 - Biochemistry/ 2023 30 Amount of Solute in a Solution How much molecules do we have in a solution?  HSF101 - Biochemistry/ 2023 31 Amount of Solute in a Solution Weight (%) (w/w) = Weight of solute in 100g solution Example: 37% HCl solution 37 g HCl Total: 100 g solution Weight of Solute g wΤw % = x 100 Weight of Solution g  HSF101 - Biochemistry/ 2023 32 Amount of Solute in a Solution Volume (%) (v/v) = Volume of solute in 100 mL solution Example: 5% EtOH solution 5 mL EtOH Total: 100 mL solution Volume of Solute mL vΤv % = x 100 Volume of Solution mL  HSF101 - Biochemistry/ 2023 33 Amount of Solute in a Solution Weight:Volume (%) (w/v) = Weight of solute in 100 mL solution Example: 5% NaCl solution 5 g NaCl Total: 100 mL solution Weight of Solute g wΤv% = x 100 Volume of Solution mL  HSF101 - Biochemistry/ 2023 34 Amount of Solute in a Solution Molarity (M) = Moles of solute in 1L solution Example: 3M NaCH2COOH 3 mol NaCH2COOH Total: 1L solution Moles of Solute n m You need to know Mw of the 𝑀= n= solute !!! Volume of Solution L MW  HSF101 - Biochemistry/ 2023 35 Acid / Base An acid is a substance that can release hydrogen ions (protons) A base is a substance that can accept hydrogen ions (protons) An amphoteric substance can do both  HSF101 - Biochemistry/ 2023 36 Acid / Base Acids will ionize to produce a proton and a base Bases will become acid after accepting a proton. conjugate base AH H+ + A- CH3COOH H+ + CH2COO- Acetic acid Acetate  HSF101 - Biochemistry/ 2023 37 Acid Conjugate Base Acetic acid Acetate Citric acid Citrate Carbonic acid (H2CO3) Bicarbonate (HCO3-) Bicarbonate (HCO3-) Carbonate (CO32-) Pyruvic acid Pyruvate Acetoacetic acid Acetoacetate The suffix «-ate» is added to acid name to make the name of conjugate base  HSF101 - Biochemistry/ 2023 38 Acids Strong acids: They essentially completely ionize in water. HCl H2SO4 Weak acids: Only a small percentage of the molecules dissociate. CH2COOH https://phet.colorado.edu/sims/html/acid-base-solutions/latest/acid-base-solutions_en.html  HSF101 - Biochemistry/ 2023 39 What is pH? pH is defined as “the negative logarithm to the base 10 of the hydrogen ion concentration” pH = -log10[H+] Why we use pH? [H+] = 10-7 M = 0.0000001 pH = 7 pH =1 10-1 M proton (0,1 M) Lots of [H+] → Acidic pH = 10 10-10 proton (0,0000000001 M) Little [H+] → Basic / Alkaline  HSF101 - Biochemistry/ 2023 40 pH and Biological Functions pH is different in different parts of the body In the blood, the pH value normally ranges only between 7.35 and 7.45  HSF101 - Biochemistry/ 2023 41 What is the importance of a bumper?  HSF101 - Biochemistry/ 2023 42 Buffer Systems Buffers are solutions that have acid-base conjugates together. Weak acid – conjugated base Weak base – conjugated acid They minimize the pH changes when an acid or a base is added to the medium HSF101 - Biochemistry/ 2023 43  HSF101 - Biochemistry/ 2023 44 Regulation of Blood pH