CHEM 211 Lessons.pdf

Beaker: Used for holding, mixing, and heating liquids and solids; ideal for non- reactive substances and general tasks. Erlenmeyer Flask: Designed for reactions that may release gases or splatter; provides better containment and mixing control. Measuring cylinder: A graduated measuring cylinder is u...

Beaker: Used for holding, mixing, and heating liquids and solids; ideal for non- reactive substances and general tasks. Erlenmeyer Flask: Designed for reactions that may release gases or splatter; provides better containment and mixing control. Measuring cylinder: A graduated measuring cylinder is used to measure volumes of liquids. Mortar and Pestle: A mortar and pestle are used to grind and mix solid substances into finer powders. Test tubes: Test tubes are used for holding, mixing, and heating small quantities of liquids and solids, can be used to grow live microorganisms such as bacteria and fungi. Test tube holder: A test tube holder is used to securely hold and handle test tubes during heating or mixing. Test tube racks: Test tube racks are used to hold and organize multiple test tubes upright. Rubber bungs: Rubber bands are used to secure items, such as test tubes or flasks, in place during experiments. Watch Glass: A watch glass is used to cover beakers or evaporating dishes and to hold small amounts of solid substances. Stirring Rod: A stirring rod is used to mix or stir liquids and solutions and to transfer a single drop of a solution. Funnel: Is used to transfer liquids or powders from one vessel to another. Pipette: A pipette is used to accurately measure and transfer small volumes of liquids. (On top is called rubber bulb). Spatulas: A spatula is used to scoop, transfer, or mix small amounts of solid chemicals. Forceps: Are used to pick up small objects. Scalpel: A scalpel is used for precise cutting or dissection of materials. Burette: A burette is used for accurately dispensing and measuring variable volumes ---------------------------------------------------------- of liquids. Bunsen burner: A Bunsen burner provides a controlled flame for heating substances (nonvolatile) Tripod: A tripod supports equipment like beakers and flasks over a flame or heat source. Gauze: Gauze is used to provide a stable surface for heating and to distribute heat evenly. Heatproof mat: A heatproof mat protects surfaces from heat damage and spills during experiments. Clay Triangle: A clay triangle supports a crucible over a heat source for heating. Evaporating Dish: An evaporating dish is used to heat liquids and evaporate solvents, leaving behind solid residues. Crucible: A crucible is used for heating substances to high temperatures and conducting reactions. Crucible Tongs: Crucible tongs are used to handle hot crucibles safely and other hot objects. Clamp stand: A clamp stand (ringstand) supports and holds laboratory equipment in place during experiments. Litmus Paper: Litmus paper is used to test the acidity or alkalinity of a solution. Universal indicator: A universal indicator tests and shows the pH level of a solution through a color change. Thermometer: A thermometer measures the temperature of substances. (mercury) Centrifuge: A centrifuge separates substances based on density by spinning them at high speeds. - Common chemistry laboratory operations include: 6. Measuring: Using tools like pipettes and 1. Mixing: Combining substances to form a burettes to determine precise volumes. solution or reaction. 7. Crystallization: Forming solid crystals from a 2. Heating: Applying heat to accelerate solution as it cools or evaporates. reactions or evaporate solvents. 8. Extraction: Isolating substances from 3. Titration: Adding a reagent to a solution to mixtures using solvents. determine its concentration. 9. Weighing: Measuring the mass of substances 4. Filtration: Separating solid particles from using a balance. liquids using a filter. 10. Observing: Monitoring physical and 5. Distillation: Purifying liquids by heating and chemical changes during experiments. condensing vapors. THE HISTORY OF CHEMISTRY Greek Model 16th and 17th Century chemistry is not “To understand the very large, we must regarded as science understand the very small” Bronze – Age Man was one of the earliest Democritus chemists. - Greek philosopher Democritus insisted that matter consists - Idea of democracy of atoms. - Idea of ‘atomos’ Atomos = indivisible Paracelsus told his pupils to use Atom is derived experiments - No experiments to support idea Boyle investigated gases and broke old - Continuous vs. Discontinuous theory traditional. Democritus’ model of atom Fire – 25% Water – 15% Earth – 31% Air – 29% No proton, electrons, or neutron - Democritus model is an empty space A BRIEF HISTORY OF CHEMISTRY In fourth century B.C., ancient Greeks Democritus proposed that matter consisted Democritus (400 BC) – First Atomic fundamental particles called atoms. Hypothesis Over the two next millennia, major Atomos: Greek for “uncuttable”. Chop up a advances in chemistry were achieved by piece of matter until you reach the atoms. alchemists. Their major role was to convert certain elements into others by a process Properties of Atoms called Transmutation. Indestructible changeable, however, into different forms THE GREEKS an infinite number of kinds so there an infinite number of elements In 400 B.C. the Greeks tried to understand matter (chemicals) and broke them down hard substances have rough, prickly atoms into earth, wind, fire, and air. that stick together Democritus and Leucippus Greek Liquids have round, smooth atoms that slide over one another philosophers smell is caused by atoms interacting with the nose – rough atoms hurt sleep is caused by atoms escaping the Empedocles (Greek, born in Sicily, 490 B.C.) brain - Suggested there were only four basic death too many escaped or didn’t return needs – earth, air, fire, and water. The the heart is the center of anger elementary substances (atoms to us) combined in various ways to make the brain is the center of thought everything. the liver is the seat of desire Democritus (Thracian, born 470 B.C.) “Nothing exists but atoms and space, all else is opinion” - Actually, proposed the word atom (indivisible) because he believed that all matter consisted of such tiny units with Four Element Theory voids between an ide quite similar to our Plato was an atomist own beliefs. It was rejected by Aristotle and thus lost for 2000 years. Thought all matter was composed of 4 elements. Aristotle (Greek, born 384 B.C) Earth (cool, heavy) Water (wet) -Added the idea of qualities – heat, cold, Fire (hot) Air (light) dryness, moisture Fire - as basic elements which combined as shown in the diagram (left side) Hot Dry Hot and dry made fire; hot and wet made Air Matter Earth air, and so on. Wet Cold ALCHEMY Water After that chemistry was ruled by alchemy Relation of four elements They believed that they could take any |Blend these elements in different cheap metals and turn into gold proportions to get all substances. Alchemist were almost like magicians Discovered distillation and Some Early Ideas on Matter recrystallization Anaxagoras (Greek, born 500 B.C) S, Hg, C, Fe, Pb, Cu, Sn, Ag, Au, P, As, Sb, Bi, Zn - Suggested every substance had its own - elixirs, physical immortality kind of seeds that clustered together to Alchemy – started in China and propagated make the substance, much as our atoms in Europe cluster to make molecules - also called pseudoscience (not true science)  - major role to convert other elements Develop lab apparatus/ procedures/ called transmutation experimental techniques - Transmutation – no chemical change - alchemists learned how to prepare involved but physical appearance only – acids fake material - developed several allow and < in ordinary chemistry, we cannot glassware transmute elements < alchemist do mixture (not substance) Early Ideas on Elements