Welcome to AP Chemistry

Transcription

1 Welcome to AP Chemistry Hello, my name is Mrs. Berry if I do not know you already. Welcome to AP Chemistry! We have a summer assignment to prepare you for the course. It covers Stoichiometry, Molecular Geometry, Writing Reactions, Redox Half Reactions, Thermochemistry and Acids & Bases. These are topics from PAP Chemistry and it would be helpful to use your PAP Chemistry notes when completing the assignment. In order to reduce the fast pace of our 1 st Six Weeks, I need you to review this information BEFORE our class starts. The summer assignment is a grade which is due our 3 rd class together next Fall. I will offer one morning of help on the Summer Assignment at Martin HS, Room 190 on Friday, August 17th from 10:00 am to 12:00 pm. You are not required to come to this session. But, I will be available to help and you can work with your peers. AP Chemistry our first quiz is our 4 th class together We will begin AP Chemistry with the assumption that you know the information in the Summer Assignment. Our first quiz will come from the topics in this Summer Assignment. If this seems like a lot of work, please remember that AP Chemistry is a college level course. AP Chemistry is designed for students who intend taking Chemistry in college. If you plan on studying anything biomedical, engineering or science related, you WILL need AP Chemistry. If you were successful in PAP Chemistry, it will take more effort to continue to be successful in AP Chemistry. If AP Chemistry were easy, everyone would do it. If you want to start AP Chemistry even stronger, my suggestion would be to work through a study guide over the summer. Here is a link to the Cliff Notes Study Guide for Chemistry which I have found to be useful. If you want an even stronger start with AP Chemistry, please start working through the Princeton Review guide for AP Chemistry. This item will be on your supply list for AP Chemistry in the Fall. So, you could purchase it now and start working with the material. My and cell number are below. Save this information in your phone and reach out to me if you have questions. Enjoy your time off and I look forward to meeting each of you. Mrs. Berry cell lberry@aisd.net As things unfold over the summer, I may need to communicate with you as a group. I will do this with the Remind app. To sign up please Enter this number: Text this 1

2 AP Chemistry Info you should already know Element Names and Symbols You will be tested on these elements in two ways. I may give the name of the element and ask for the symbol, or I may give the symbol and ask for the name (correct spelling!) Hydrogen H Lithium Li Boron B Copper Cu Arsenic As Bromine Br Helium He Beryllium Be Carbon C Zinc Zn Selenium Se Rubidium Rb Strontium Sr Neon Ne Plutonium Pu Oxygen O Tin Sn Sodium Na Silver Ag Cobalt Co Antimony Sb Fluorine F Uranium U Magnesium Mg Cadmium Cd Nickel Ni Iodine I Aluminum Al Cesium Cs Silicon Si Gold Au Francium Fr Barium Ba Calcium Ca Iron Fe Phosphorus P Bismuth Bi Radium Ra Tungsten W Chromium Cr Argon Ar Sulfur S Astatine At Mercury Hg Platinum Pt Nitrogen N Chlorine Cl Manganese Mn Potassium K Lead Pb Diatomic Molecules H2 N2 O2 F2 Cl2 Br2 I2 2

3 Ion Names and Charges (oxidation Numbers) Transition metals (plus tin and lead) can often form multiple ions. The only major exceptions to this rule are silver, zinc, and cadmium, which form only Ag 1+, Zn 2+, and Cd 2+, with no other ions being formed. This tendency to form different ions is the reason we have to use Roman numerals in the names of compounds of transition elements to identify which ion is present. (For example, iron (II) oxide when the Fe 2+ ion is present or iron (III) oxide when the Fe 3+ ion is present.) Names, Formulas, and Charges of Some Common Ions Al 3+ Aluminum Au 3+ Gold (III) or auric Fe 3+ Iron (III) or ferric H - Hydride Sn 2+ Tin (II) or stannous Co 2+ Cobalt (II) or cobaltous Mn 2+ Manganese (II) Sn 4+ Tin (IV) or stannic Co 3+ Cobalt (III) or cobaltic Ni 2+ Nickel (II) Pb 2+ Lead (II) or plumbous Cu + Copper (I) or cuprous Zn 2+ Zinc Pb 4+ Lead (IV) or plumbic Cu 2+ Copper (II) or cupric Cd 2+ Cadmium Cr 2+ Chromium (II) or chromous Hg2 2+ Mercury (I) or mercurous Ag + Silver Cr 3+ Chromium (III) or chromic Hg 2+ Mercury (II) or mercuric Au + Gold (I) or aurous Fe 2+ Iron (II) or ferrous Common Monatomic Ions and Their Charges Periodic Table Group/Region Group 1, Alkali metals Ion Charge Notes +1 only Roman numerals not needed. H is the exception. It can have a +1 charge (as an acid) or a -1 charge (as a hydride with a metal). +2 only Roman numerals not needed. Group 2, Alkaline Earth Group 17, -1 in ionic compounds Halogens Group 16-2 charge when monatomic Sulfur and oxygen can form polyatomic ions that can be misleading. Peroxide ion is O2-2, for example. Transition Variable, many transition Use Roman numerals. The exceptions are Ag +1, Zn +2, metals metals have more than one and Cd +2. These don t form other ions and don t need p-block Metals possible charge. Variable, many have more than one possible charge. Some of the semi-metals can form positive or negative ions. Roman numerals. Use Roman numerals. The exceptions are Al +3 and Po +2. 3

4 Rules for Determining Oxidation Number Oxidation Number: A number assigned to an atom in a molecular compound or molecular ion that indicates the general distribution of electrons among the bonded atoms. 1. The oxidation number of any uncombined element is zero. 2. The oxidation number of a monatomic ion equals the charge on the ion. 3. The more electronegative element in a binary compound is assigned the number equal to the charge it would have if it were an ion. 4. The oxidation number of fluorine in a compound is always 1 5. Oxygen has an oxidation number of 2 unless it is combined with F, when it is +2, or it is in a peroxide, when it is The oxidation state of hydrogen in most of its compounds is+1 unless it combined with a metal, in which case it is In compounds, the elements of groups 1 and 2 as well as aluminum have oxidation number of +1, +2, and +3, respectively 8. The sum of the oxidation numbers of all atoms in a neutral compound is zero. 9. The sum of the oxidation numbers of all atoms in a polyatomic ion equals the charge of the ion. Solubility Rules 1. All compounds containing alkali metal cations (group#1) and the ammonium ion are soluble. 2. All compounds containing -3, ClO4 1-, ClO 3-, and C2H3O2 - anions are soluble. 3. All chlorides, bromides, and iodides are soluble except those containing Ag +, Pb 2+, or Hg All sulfates are soluble except those containing Hg 2+, Pb 2+, Sr 2+, Ca 2+, or Ba All hydroxides are insoluble except compounds of the alkali metals, Ca 2+, Sr 2+, and Ba All compounds containing PO4 3-, S 2-, CO3 2-, and SO3 2- ions are insoluble except those that also contain alkali metals or NH4 +. Rules for Naming Ionic Compounds 1. Balance Charges (charges should total to zero) 2. Cation is always written first (in name and in formula) 3. Change the ending of the anion to -ide 4

5 Rules for Naming an Acid 1. When the name of the anion ends in ide, the acid name begins with the prefix hydro-, the stem of the anion has the suffix ic and it is followed by the word acid. -ide becomes hydro ic Acid Example: Cl - is the Chloride ion so HCl = Hydrochloric acid 2. When the anion name ends in ite, the acid name is the stem of the anion with the suffix ous, followed by the word acid. -ite becomes ous Acid Example: ClO2 - is the Chlorite ion so HClO2 = Chlorous acid 3. When the anion name ends in ate, the acid name is the stem of the anion with the suffix ic, followed by the word acid. -ate becomes ic Acid Example: ClO3 - is the Chlorate ion so HClO3 = Chloric acid. Strong Acids and Strong bases You need to know which acids and bases are strong and which are weak. Strong Acids: Strong acids are 100% ionized in aqueous solution to form the hydronium ion, H3O + (also written as H + (aq)) and the anion. Memorize these Strong Acid: HCl (hydrochloric acid), HBr (hydrobromic acid) HI (hydroiodic acid) H3 (nitric acid) H2SO4 (sulfuric acid) HClO4 (perchloric acid) HClO3 (chloric acid) Strong bases: Strong Bases are 100 % ionized in aqueous solution to form the hydroxide ion, OH, and the cation Memorize these strong bases: Alkali metal hydroxides (1A) LiOH; NaOH; KOH; RbOH; CsOH Alkaline earth hydroxides (2A): Ca(OH)2; Sr(OH)2; Ba(OH)2 5

6 Common Polyatomic Ions Polyatomic ions - these are ions that include more than one element, but they remain together as a group and have one overall charge for the group of atoms involved. Memorize the names, formulas and charges for the polyatomic ions listed below. -1 ions C2H3O2 - Acetate ClO - Hypochlorite SCN - Thiocyanate CN - Cyanide ClO2 - Chlorite HSO4 - Hydrogen sulfate OH - Hydroxide ClO3 - Chlorate HCO3 - Hydrogen carbonate 2 - Nitrite ClO4 - Perchlorate MnO4 - Permanganate 3 - Nitrate BrO3 - Bromate IO3 - Iodate -2 ions CO3 2- Carbonate SO3 2- Sulfite HPO4 2- Hydrogen phosphate S2O3 2- Thiosulfate SO4 2- Sulfate CrO4 2- Chromate C2O4 2- Oxalate O2 2- Peroxide Cr2O7 2- Dichromate O2 1- Superoxide -3 ions PO4 3- PO 3 3- Phosphate Phosphite +1 ions NH4 1+ H3O 1+ Ammonium Hydronium +2 ions Hg2 2+ Hg 2+ Mercury(I) ion Mercury(II) ion 6

7 IMF also known as: In Intermolecular forces Dipole interactions Dispersion factors Intramolecular Forces (IMF) Flowchart Is the species ionic? van de Waals Forces Is the species symmetrical? Compare the two species. Do they have the same oxidation numbers (charges) on the ions? Species is non-polar. IMF = London Dispersion Forces Species is polar. Is H bonded to N, O or F? (Cl & S form weaker Hydrogen bond) Look at the size of the atoms the larger (atomic size) the element, the weaker the attraction the lower the boiling point & freezing point and the weaker the lattice energy is. Look at the charges, the bigger the charge the stronger the attraction the higher the boiling point & freezing point and the stronger the lattice energy is. Weakest LDF-instant; induced dipole; short lived; weak Compare # of e- the more they have, the stronger the LDF. Key word polarizable electrons Are there unpaired electrons on N, O or F? IMF = Hydrogen bonding. Strongest IMF Answer is based on Hydrogen bonding. IMF = Dipole to dipole Look at difference of electroneg. values, farther apart more polar -LDF (induced dipole to dipole; force incr w M.W.) -Dipole to dipole -Hydrogen bond (10% strength of Cov. Bond) -Covalent Bond -Ionic Band Strongest Strength of LDF depends on the size of the e - cloud. Polarizability - how easily the charge distribution can be shifted by an external electrical field. 7