Introduction to Chemistry Lecture 1.1 PDF

Internal Use Introduction to Chemistry Internal Use Water The water molecules is a polar molecule which also creates hydrogen bonds between water molecules. 2 Intern...

Internal Use Introduction to Chemistry Internal Use Water The water molecules is a polar molecule which also creates hydrogen bonds between water molecules. 2 Internal Use Hydrogen bonding in water There is constant breakage and formation of hydrogen bonds in water. Water: 2.3 H-bonds Ice: 4 H-bonds 3 Internal Use Non-covalent Interactions Ionic Bonds (+) and (-) molecules Electrostatic Interactions (+) and (-) ions Hydration of Ions in Solution 4 Internal Use Non-covalent Bonding Hydrogen bonds Water, Amines, Alcohols, Carboxylic Acids Van der Waals forces Unequal distribution of electrons Hydrophobic interactions Occurs only in aqueous environment and tendency for hydrophobic molecules to coalesce 5 Internal Use Water: the universal solvent Ionic compounds Polar compound Amphipathic molecules Micelles 6 Internal Use Properties of water Liquid at normal temperature High Boiling Point and Melting point High heats of fusion and vaporization High heat capacity Surface tension 7 Internal Use Acids and Bases Acids: proton donor Base: proton acceptor Strong Acids and Bases Weak acids and bases; conjugates 8 Internal Use Buffers Solution of weak acid (HA) and conjugate base (A-) Resist a large change in pH of a solution The acid “absorbs” base. The base “absorbs” acid. 9 Internal Use Buffer Capacity Molar concentration of acid and base Ratio of acid and base Effective when pH = -+ 1 unit of pKa 10 Internal Use Henderson-Hasselbach Equation Equation for determining several aspects of any given buffer. 11 Internal Use Biological Buffers Bicarbonate: Blood pKa = 6.37, pH of blood = ~7.4 Blood pH controlled by respiration and kidneys. 12 Internal Use Biological Buffers Phosphate: intracellular pKa = 7.2 Important for phosphorylation Proteins: both intracellular and blood (hemoglobin) 13 Internal Use Control of Blood pH Lungs and Kidneys Lungs excrete carbon dioxide Kidneys excrete H+ by two major routes: 1. Ammonia 2. Phosphate *most bicarbonate is reabsorbed 14 Internal Use pH Conditions pH < 7.35, Acidosis pH > 7.45 Alkalosis 15 Internal Use Respiratory Acidosis Depression of respiratory rate Increases CO2 in blood Increases bicarbonate retention in kidney Lowers pH Hyperventilation Lowers CO2 in blood Lowers protons for kidney excretion Lowers reabsorption of bicarbonate and sodium Increases pH 16 Internal Use Respiratory Acidosis Depression of respiratory rate Increases CO2 in blood Increases bicarbonate retention in kidney Lowers pH Hyperventilation Lowers CO2 in blood Lowers protons for kidney excretion Lowers reabsorption of bicarbonate and sodium Increases pH 17 Internal Use Metabolic Acidosis Something causes the lowering of plasma bicarbonate Increased metabolism acids (e.g. lactic acid – during intense workout) Increased ketone bodies Loss of bicarbonate (diarrhea) Kidney failure resulting to low proton excretion 18 Internal Use Metabolic Alkalosis Something causes the increase in plasma bicarbonate Often a result of excessive vomiting Excessive excretion of protons 19 Internal Use Matter, Energy, and Measurements “Everything around us is made up of chemicals. From the color of the sky to the soap you use for washing your hands, these are all because of chemistry that we experience on a daily basis.” 20 Internal Use Matter, Energy, and Measurements The universe is composed of matter, energy, and empty space. Matter is anything that has mass and occupies space. Chemistry is the science that deals with matter. Structure and properties of matter and the transformation from one form of matter to another. 21 Internal Use Matter, Energy, and Measurements Energy can also be used to change from one form of matter to another. This is called Chemical change or reaction. Example: burning of hydrocarbons Matter can also undergo other change called Physical Change. Usually involve the change of state of matter without changing the identity of the substance. Example: evaporation of water 22 Internal Use The Scientific Method The Scientific Method is the systematic way of investigating a problem. Fact is a statement based on direct experience. Hypothesis is a statement that is proposed, without actual proof, to explain the facts and their relationship. Theory is the formulation of an apparent relationship among certain observed phenomena. 23 Internal Use The Scientific Method Steps: 1. Introduction – Objectives, Scope and Limitations, etc. 2. Methods 3. Results and Discussion 4. Conclusion 24 Internal Use Scientific Notation Steps: 1. Nonzero digits are always significant. 2. Zeros at the beginning of a number are never significant. 3. Zeros between nonzero digits are always significant. 4. Zeros at the end of a number that contains a decimal point are always significant. 5. Zeros at the end of a number that contains no decimal point may or may not be significant. 25 Internal Use Scientific Notation Add 1.95x10-2 and 2.8x10-3 Multiply 7.40x105 and 3.12x109 Divide 1.62x10-4 and 7.94x107 26 Internal Use Scientific Notation Add 1.95x10-2 and 2.8x10-3 Answer: 2.23x10-2 Multiply 7.40x105 and 3.12x109 Answer: 2.31x1014 Divide 1.62x10-4 and 7.94x107 Answer: 2.04x10-12 27 Internal Use Measurements We are constantly making measurements on a daily basis. From recipes, driving distances, gallons of water, and weights of product, we use measurements. Measurements consist of 2 parts: Number and Unit. 28 Internal Use Measurements a. Length – Meter b. Volume – Liter c. Mass – Gram d. Time – Seconds or Hours e. Temperature – Celsius 29 Internal Use Measurements Common Metric Prefixes 1. Giga – 109 2. Mega – 106 3. Kilo – 103 4. Deci – 10-1 5. Centi – 10-2 6. Milli – 10-3 7. Micro – 10-6 8. Nano – 10-9 9. Pico – 10-12 30 Internal Use Measurements Common Metric Prefixes 1. Giga – 109 2. Mega – 106 3. Kilo – 103 4. Deci – 10-1 5. Centi – 10-2 6. Milli – 10-3 7. Micro – 10-6 8. Nano – 10-9 9. Pico – 10-12 31 Internal Use Unit Conversion A Physician recommends adding 100. mg of morphine to 500. cc of IV fluid and administering it at a rate of 20. cc/h to alleviate a patient’s pain. Determine how many grams per second the patient is receiving. 32 Internal Use States of Matter Matter can exist in three states: Solid, Liquid, and Gas. Gases have no definite shape or volume. Liquids are only slightly compressible. Solids have definite shape and definite volumes. 33 Internal Use Density and Specific Gravity Density of any substance is defined as its mass per unit volume. Example: If 73.2 mL of a liquid has a mass of 61.5g, what is the density in g/mL? 34 Internal Use Density and Specific Gravity Specific Gravity is numerically the same as density but has no units. The reason is that SG is defined as a comparison of the density of a substance to the density of water. Example: The density of ethanol at 20C is 0.789. What is the specific gravity of ethanol? 35 Internal Use 36