Introduction to Chemistry Chapter 11 Student Learning Objectives Distinguish between physical & chemical properties Classify, compare, name, & identify chemical quantities Recall properties of solubility Apply trends in the periodic table. What is chemistry? Chemistry is the study of microscopic properties. Chemical properties Invisible How and why atoms combine into molecules What are some physical and chemical properties? Physical Properties (Macroscopic) Density Phase Appearance Size Chemical Properties (Microscopic) Atomic make-up Structure Reactivity Practice 1)How many different medicines exist for pain relief? 2)Is surface tension a microscopic or macroscopic property of matter? 3)What does the image show? Is it an example of a physical or chemical property? More Practice 4)Name the macroscopic properties of water. 5)Name the microscopic properties of water. 6)How do carbon dioxide (CO 2 ) and water (H 2 O) compare and contrast? Some Chemical Change Indicators The primary difference between a physical change and a chemical change is that a chemical change produces a new substance. Color change Production of a Gas Temperature Change Light Sound How are elements, molecules, compounds & mixtures defined? Question Question: What are the origins of the elements? A compound contains two or more types of atoms. TypeNumber of Atoms Diatomic2 Triatomic3 Polyatomic4+ Practice 1)Which is not a compound? 2)How many atoms are contained in each? 3)Classify as diatomic, triatomic, or polyatomic. H2OH2OCaF 2 NH 3 O2O2 Classifying Mixtures A substance that is pure has only one type of element, or molecule, present. Copper Salt A mixture contains two or more distinct types of substances (atoms/molecules). Homogeneous Mixture Same uniform appearance and composition throughout Solution (same phase) Heterogeneous Mixture Consists of visibly different substances and/or phases Suspension (particles settle) Practice: Practice: Classify Each Substance 7-up Aluminum Homogenized milk Raw milk Oil and water Carbon monoxide Distilled water Air Tap water How can mixtures be separated? Water may cross a semi-permeable membrane. (Osmosis) Osmosis: from less to more concentrated Reverse osmosis: from more to less concentrated Question Why are distillation and desalination typically not used to obtain fresh water from salt water? What is solubility? Solubility is a measure of how much solute will dissolve in a solvent to produce a stable solution. Water & Sugar Solvent (larger amount) Does the dissolving Solute (smaller amount) Dissolves Oil & Water Liquids may be miscible or immiscible. (mix or not mix) Solubility is variable. Bond Strength Bond Types Temperature Pressure Molecular attractions Solubility has a limit, based on each individual substance and physical conditions. Concentrated Dilute Saturated Concentration = Grams Liter Practice 1)If you cannot dissolve anymore sugar in your coffee, your coffee is? 2)What is the concentration when 5 grams of sugar is added to a liter of water? 3)If you have 30 mL of 25% HCl solution, how many grams of HCL are in the solution? What are the basic trends in the periodic table? The periodic table is periodic! Most of the elements in the periodic table are metals. Shiny Opaque Good Conductors Trends Chemical reactivity decreases L R Radius decreases along a period L R Ionization energy increases along a period L R Practice 1)Which metals are liquid under normal atmospheric conditions? 2)Which of the following would be most reactive? a. O b. He c. Al d. Cl 3)Which of the would have the smallest radius? a. Al b. Cl Atomic Periods (rows) are periodic. Atomic Groups (columns) have similar trends. 1 amu = x grams GroupNameAttributes IAAlkali Metals Highly Reactive IIAAlkali Earth Metals MiddleTransition Metals High Melting Point IIIAMetalloids Metals/ Non-metals VIA Ore Forming Elements VIIAHalogen Gases Salt Forming Elements VIIIANoble Gases Non-Reactive Emerald is a variety of beryl, a mineral that contains the alkaline earth metal beryllium. Lanthanides (58-71): found in geologic zones Actinides (90-103): most are synthesized in labs A Uranium Rock Practice 1)In which group are the precious metals? 2)List all attributes of Bromine (Br) that can be determined using the periodic table. What does the shell model indicate? No two electrons can have the exact same energy state. (Pauli Exclusion Principle) Electrons are arranged in particular orbitals Each electron has its own set of quantum numbers (n,l,m l, m s ) which determine the energy state of the electron Atomic period indicates the number of main energy shells available in the ground state. ShellMaximum e - Allowed n = 12 n = 28 n = 38 n = 418 n = 518 n = 632 n = 732 Practice Draw the electron configuration for each atom. (Assume atoms in ground state) 1. N 2. Kr 3. Mg 4. O Electrons attempt to have configurations that match those in group VIIIA. (Octet Rule) Valence electrons are what make the physical and chemical properties of the atoms in a group similar. 8 Group Number = Number Unpaired e Valence Electrons More unpaired electrons = more reactive Unpaired valence electrons are used to form chemical bonds What are some rules for naming compounds? Compounds Metal is named first and then the Non-metal NaCl = Sodium Chloride HF = Hydrogen Fluoride Prefixes CO 2 = Carbon Dioxide 1.Mono 2.Di 3.Tri 4.Tetra 5.Penta 6.Hexa 7.Hept 8.Oct Left then Right + ide Polyatomic Ions Polyatomic Ions are molecules made up of two or more atoms that are considered an ionic group, that have charge. 1.Name the cation (+ ion) first 2.Name the anion (- ion) second + ate CaCO 3 Calcium Carbonate Practice What is the chemical name? Does it have a common name? 1. O 2 5. SF 6 2. H 2 O6. CH 4 3. KBr7. NH 3 4. O 3 8. PCl 5 Practice with Polyatomic Ions What is the chemical name? Does it have a common name? 1. AlPO 4 4. Fe(NO 3 ) 2 2. Cu 2 SO 4 5. NaHCO 3 3. KClO 3 6. NaH 2 PO 4