CHEMISTRY 11 Notes - Mrs. Jeffrey This is a compilation of miscellaneous notes that I have assembled for use in the CHEM 11 course. I do not expect you to just print out every page in a wholesale fashion, as you can always access this from your computer whenever the need arises. I will not remove this file from my homework page before the end of the course. It will always be accessible to you from the web (either at home or at school). These pages appear in the order they are used in the course. Chapters may appear to be out order. Study Worksheet for Chemistry Math Review 1. Completely read the chapter. 2. Define the Key Terms at the end of the chapter. 3. Be familiar with the scientific method (P. 5). 4. Know how to apply the rules for determining the number of significant figures (s.f.) in a number. Also know the 3 rules that aren't in the book: a) a mathematical definition or equivalence (e.g. exactly 12 in. = 1 ft), has infinite s.f., b) an integer number (e.g. 3 atoms, or 6 people) also has infinite s.f., and c) all of the digits in a scientific notation number (e.g. 3.30 x 103) are always significant. 5. Know how many significant figures should be in the answer to any mathematical calculation, based upon the number of s.f. in the problem (one rule is used for x and /, and another rule is used for + and - ). 6. Be able to round off any number to any number of significant figures. 7. Be able to convert any common number into scientific notation and vice versa. 8. Know all of the metric prefixes in bold on P. 20, and what they mean, so you can change one into another, (e.g. 100 cm = 1 m, 100 mg = 1 dg, 1000 uL = 1 mL, 10 cm = .1 m, etc.), and can tell which of 2 numbers are the largest and by how much (i.e. 1 cm is 10 times larger than 1 mm). 9. Know the SI unit and its abbreviation for the first 5 items in Table 2.2 on P. 20. 10. Know how to solve dimensional analysis problems (like on P. 23 - 29). 11. Always answer all numerical questions with both the correct scientific units and the correct number of significant figures. 12. 1 cm3 = 1 mL , which is also equal to 1 g when describing water only. 1,000 cm3 = 1 L , which is also equal to 1 kg when describing water only. 13. Know the 7 terms used to describe phase changes: melt, boil, evaporate, vaporize, sublime, freeze & condense. 14. Convert any temperature into the other 2 systems using: (9/5)C = F - 32 and K = C + 273 15. Density = mass / volume. Solve for any unknown if you are given the other 2 values. 16. When 2 substances are mixed, the higher density substance will always sink to the bottom. 17. You don't need to memorize the numbers, but have a good qualitative appreciation for which substances are the most and least dense in Table 2.5 (P. 35). These notes pertain to the Pictorial Period Table that is attached to the wall in my classroom. Important Notes about the Period Table 1) All of the Noble Gases (Group VIIIA) are colorless gases. In these pictures, an electric current is arcing through the tubes containing these gases, which then give off these bright colors that are characteristic of each element (e.g. red-orange for Ne, lavender for Ar, etc.). 2) Most of the elements above U do not exist in nature. They are man-made and all quantities must be synthesized in the lab from other elements. So these elements can’t be produced in large quantities and usually decay radioactively within seconds. Consequently, there often isn't a sufficient amount available -- even to just photograph. Therefore, some of these elements don’t have any picture, while others instead show a picture of a compound (usually an oxide) made from that element. Most of these elements are metals, so if we had pictures of the pure elements, they would look like any other silver metal. 3) The RaO sample is green only because it had previously absorbed light energy and is now slowly re-radiating its characteristic green light. It was formerly used in watch dials that glow in the dark. Chemical Identity of Common Household Materials Household items are typically impure mixtures, with the following as the main ingredient (other than H2O): Item Acetylene welding Ammonia Antifreeze (car) Aspirin Baking soda Bleach Brass Cane sugar Car battery acid Citrus fruits & candy Cream of Tarter Dental fillings Drano, lye, oven cleaner Dry ice Epsom salts Grain alcohol (drinking) Low sodium salt Milk of Magnesia Mothballs Muriatic acid Formula C2H2 NH3 C2H4(OH)2 C9H8O4 NaHCO3 NaClO Cu, Zn C12H22O11 H2SO4 H2C6H6O7 KHC4H4O6 Ag, Hg NaOH CO2 MgSO4.7H2O C2H5OH KCl Mg(OH)2 C10H8 HCl Name acetylene or ethyne ammonia (actually ammonia water) ethylene glycol acetylsalicylic acid sodium bicarbonate sodium hypochlorite copper and zinc mixture sucrose sulfuric acid citric acid or 2-hydroxy-1,2,3-propanetricarboxylic acid potassium hydrogen tartrate silver and mercury mixture sodium hydroxide carbon dioxide magnesium sulfate heptahydrate ethyl alcohol potassium chloride (substitute salt) magnesium hydroxide naphthalene hydrochloric acid Nail polish remover Natural gas Peroxide Rubbing alcohol Rolaids Rust Soft Drinks Spot remover Stainless steel Sterling silver Table salt Teflon Tums, chalk Vinegar Vitamin A Vitamin B12 Vitamin C Vitamin E 12 karat gold CH3COCH3 CH4 H2O2 C3H7OH Al(OH)3 FeO, Fe2O3 H2CO3 C2H3Cl3 Fe, Cr, Ni, C Ag, Cu NaCl [-CF2-CF2-]~1000 CaCO3 HC2H3O2 C20H30O C63H88CoN14O14P C6H8O6 C29H50O2 Au, Ag, Cu acetone methane (95%) hydrogen peroxide isopropyl alcohol aluminum hydroxide iron II oxide and iron III oxide carbonic acid (H2O + CO2) trichloroethane iron, chromium, nickel and carbon mixture silver and copper mixture sodium chloride polytatrafluoroethylene calcium carbonate acetic acid (very long name) 5,6-dimethylbenzimidazolylcyanocobamide ascorbic acid 2,5,7,8-tetromethyl-2-(4',8'12'-trimethyltridecyl)-6-chromanol gold, silver and copper mixture Study Worksheet for Chapter 11 1. Define an orbital – a geometric figure resulting from quantum mechanics that predicts where an electron is most likely to be with respect to the nucleus. Each orbital can hold up to 2 e-s. 2. Using this orbital chart, write out the full electron configuration for all elements up through Kr (36). E.g. Br = 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5 3. What does 2p4 mean? There are 4 electrons in the 2p orbitals (and there are always 3 p orbitals – one in each of the x, y & z directions). Two electrons are in the first 3p orbital, one electron is in the second 3p orbital, and one electron is in the third 3p orbital. 4. For any element, identify how many electrons or in the highest energy level. E.g. Br = 4p5 5. Given an electronic configuration, identify the atom. (just add up the exponents) E.g. 1s2 2s2 2p4 -- 2+2+4=8 electrons = 8 protons = Oxygen (atomic number = 8). 6. Given an electronic configuration, state whether its in its ground state, its excited state, or its illegal. E.g. 1s2 2s8 2p6 3s2 3p6 4s2 3d10 4p5 Illegal -- an s orbital can’t hold more than 2 electrons 2 2 6 2 10 5 1s 3s 3p 4s 3d 4p Excited -- the entire 2nd principle level was left out (electrons promoted) 1s2 2s2 2p2 3s2 3p2 4s2 3d10 4p5 Excited -- the lower p orbitals aren’t fully filled (electrons promoted) 2 2 6 2 6 2 1s 2s 2p 3s 3p 3d Excited -- the 4s orbital fills before the 3 d orbital (electrons promoted) 1s2 1p6 2s2 2p6 3s2 3p6 Illegal -- there is no such thing as a 1p orbital 1s2 2s2 2p6 2d10 3s2 Illegal -- there is no such thing as a 2d orbital 7. Given any group in the periodic table, identify what is common to the outermost electron shell of each element. E.g. in Group IA, all elements have only 1 electron in the outer s orbital. 8. What do s orbitals look like? p orbitals? 9. The 4th principle energy level can hold up to how many electrons? 2 + 6 + 10 + 14 = 32. 10. Compare the major differences between the Thomsom model, the Rutherford model, the Bohr model and the Quantum Mechanical model of the atom. 11. Define quantum – a small, discrete quantity of energy in an atom. One or more quanta units of energy are required to move electrons between the various atomic energy levels. 12. In any particular principle energy level, how many s orbitals are there? (1), p orbitals? (3), d orbitals? (5), f orbitals? (7) How many electrons can fit in any orbital? (2). Therefore, how many electrons can fit in the one s orbital (2), the three p orbitals (6), the five d orbitals (10), the seven f orbitals (14)? 13. How does filling effect the stability of an orbital? Fully-filled and fully-empty orbitals are very stable. Halffilled are somewhat stable. Any other kind of partially-filled orbital is unstable. 14. Explain why atoms emit a color spectrum. Electrons moving from higher energy levels to lower energy levels emit light (photons). The lines in emission spectra can be correlated to the movement of these electrons back to their lower energy levels (ground states). Why is each atom’s spectra unique? 15. Give electron configurations for elements beyond Kr (36). Principal Energy Levels, Sublevels and Orbitals - Chapter 11 • • • Principal Energy Level 1 2 Number of Sublevels 1 2 3 3 4 4 5 5 6 6 7 7 8 Etc. 8 Etc. Sublevel Name 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f (5g) 6s 6p 6d (6f) (6g) (6h) 7s 7p (7d) (7f) (7g) (7h) (8s) Etc. # of Orbitals in this Sublevel 1 1 3 1 3 5 1 3 5 7 1 3 5 7 (9) 1 3 5 (7) (9) (11) 1 3 (5) (7) (9) (11) (1) Etc. # of electrons in this Sublevel 2 2 6 2 6 10 2 6 10 14 2 6 10 14 (18) 2 6 10 (14) (18) (22) 2 6 (10) (14) (18) (22) (2) Etc. Be careful to distinguish between the words: principal energy level, sublevel and orbital. These words have different meanings and are not interchangeable. The sublevels in parentheses are not used in the ground state of the present 109 elements. When more elements are discovered (i.e., synthesized), they will then begin to use these sublevels. Also, when electrons are excited, they may briefly occupy these levels, then return to their ground states. Generally, energy increases as you go from the top line down through the lower lines, but not exactly. Beginning at the 3d sublevel, the sublevels no longer fill in the exact order indicated. The correct order can always be obtained from the Periodic Table. Electron Configurations and Orbital Diagrams - Chapter 11 Z El Electron Configuration 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 1s1 1s2 1s2 2s1 1s2 2s2 1s2 2s2 2p1 1s2 2s2 2p2 1s2 2s2 2p3 1s2 2s2 2p4 1s2 2s2 2p5 1s2 2s2 2p6 1s2 2s2 2p6 3s1 1s2 2s2 2p6 3s2 1s2 2s2 2p6 3s2 3p1 1s2 2s2 2p6 3s2 3p2 1s2 2s2 2p6 3s2 3p3 1s2 2s2 2p6 3s2 3p4 1s2 2s2 2p6 3s2 3p5 1s2 2s2 2p6 3s2 3p6 1s2 2s2 2p6 3s2 3p6 4s1 1s2 2s2 2p6 3s2 3p6 4s2 1s2 2s2 2p6 3s2 3p6 4s2 3d1 1s2 2s2 2p6 3s2 3p6 4s2 3d2 1s2 2s2 2p6 3s2 3p6 4s2 3d3 1s2 2s2 2p6 3s2 3p6 4s1 3d5 (*) 1s2 2s2 2p6 3s2 3p6 4s2 3d5 1s2 2s2 2p6 3s2 3p6 4s2 3d6 1s2 2s2 2p6 3s2 3p6 4s2 3d7 1s2 2s2 2p6 3s2 3p6 4s2 3d8 1s2 2s2 2p6 3s2 3p6 4s1 3d10 (*) 1s2 2s2 2p6 3s2 3p6 4s2 3d10 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p1 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p2 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p3 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 Orbital Diagram 1s [↑ ] [↑↓] 2s [↑↓] [↑ ] [↑↓] [↑↓] 2p [↑↓] [↑↓] [↑ ][ ][ ] [↑↓] [↑↓] [↑ ][↑ ][ ] [↑↓] [↑↓] [↑ ][↑ ][↑ ] [↑↓] [↑↓] [↑↓][↑ ][↑ ] [↑↓] [↑↓] [↑↓][↑↓][↑ ] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] [↑↓] [↑↓] [↑↓][↑↓][↑↓] 1s 2s 2p 3s [↑ ] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] 3s 3p [↑ ][ ][ ] [↑ ][↑ ][ ] [↑ ][↑ ][↑ ] [↑↓][↑ ][↑ ] [↑↓][↑↓][↑ ] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓] 3p 4s [↑ ] [↑↓] [↑↓] [↑↓] [↑↓] [↑ ] [↑↓] [↑↓] [↑↓] [↑↓] [↑ ] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] [↑↓] 4s {your textbook stops on this line} 3d [↑ ][ ][ ][ ][ ] [↑ ][↑ ][ ][ ][ ] [↑ ][↑ ][↑ ][ ][ ] [↑ ][↑ ][↑ ][↑ ][↑ ] [↑ ][↑ ][↑ ][↑ ][↑ ] [↑↓][↑ ][↑ ][↑ ][↑ ] [↑↓][↑↓][↑ ][↑ ][↑ ] [↑↓][↑↓][↑↓][↑ ][↑ ] [↑↓][↑↓][↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓][↑↓][↑↓] [↑↓][↑↓][↑↓][↑↓][↑↓] 3d (*) (*) 4p [↑ ][ ][ ] [↑ ][↑ ][ ] [↑ ][↑ ][↑ ] [↑↓][↑ ][↑ ] [↑↓][↑↓][↑ ] [↑↓][↑↓][↑↓] 4p The * indicate elements where the electron configuration is slightly different than what you would guess. One electron from the 4s sublevel is promoted up the 3d sublevel making it either half full, or entirely full. Study Worksheet for Chapter 11 VSEPR Model - Chem 11 Extremely Important Note: After printing this page, you MUST draw in the missing dots on all 6 Lewis dot structures (its the horizontal pairs of dots can't be produced by MS Word). Lewis dot structures only show which atoms are bonded to which other atoms, how many electrons are involved in the bonds, and how many are lone pairs. It is a flat representation. It does not show the molecule's true 3-D structure. Steps to determine the compound's real 3-D structure: 1) First draw the Lewis dot structure. 2) Determine how many different groups of electrons surround each central atom. 3) Choose the appropriate geometric orientation that describes the placement of the atoms where the electrons move the farthest apart from each other in 3-D space. This is different than how they would move apart from each other in 2-D space when constrained to the plane of a sheet of paper. Note that the geometric orientation of the atoms will be different than the geometric orientation of the electrons for central atoms that have 1 or more lone pairs of electrons. Formula # of e- densities around the central Structure atom Geometric Shape CO2 :O : : C : : O: 2 linear (2 e- densities around C try to get the farthest away) BF3 :F: 3 trigonal planar (3 e- densities around B try to get the farthest away) :F: B :F: H2O H:O:H 4 bent (4 e- densities around O, but 2 have no atoms attached to them) So the e- densities form a tetrahedral, but the atoms form a bent angle. CH4 H H:C:H H 4 tetrahedral (4 e- densities around C try to get the farthest away) 4 pyramidal (4 e- densities around N, but 1 has no atom attached to it) So the e- densities form a tetrahedral, but the atoms form a pyramid. NH3 H:N:H H :F: :F: SF6 :F : S : F: 6 octahedral (e- densities around S) - this is not in your book :F: :F: Chapter 5 - Naming Inorganic Compounds In order to correctly name an inorganic chemical compound from its formula, you must first determine the type of compound it is, and then select the appropriate naming rule to use. Lower case is always used. IONIC COMPOUND (a representative metal and one or more non-metals) a) Binary compound where the metal has only 1 ionic charge state1 Name Rule: full metal name root form of the non-metal + -ide Examples: NaCl = sodium chloride, MgH2 = magnesium hydride, AlN = aluminum nitride b) Binary compound where the metal has multiple ionic charge states2 Name Rule: full metal name + (roman numeral) root form of the non-metal + -ide Examples: CuF2 = copper (II) fluoride, Fe2O3 = iron (III) oxide, Hg2S = mercury (I) sulfide c) Polyatomic compound where one ion consists of a group of atoms (usually the anion) Name Rule: use (a) or (b) rule, and the ion table in your textbook for the anion name Examples: KMnO4 = potassium permanganate, NH4NO3 = ammonium nitrate MOLECULAR COMPOUND (two non-metals) a) Binary compound consisting of only non-metals Name Rule: prefix + element prefix + root form of last element + -ide a) If there is only 1 atom of the 1st element, the mono prefix is dropped. b) Also, if the 2nd element begins with a vowel and its prefix ends with a vowel, then the 1st vowel is dropped. Examples: NO2 = nitrogen dioxide, CCl4 = carbon tetrachloride, N2O = dinitrogen monoxide ACID (contains hydrogen at the beginning of the formula and reacts by losing that hydrogen atom) a) A binary acid (hydrogen and only one other atom)3 Name Rule: hydro + root of anion + -ic acid Examples: HCl = hydrochloric acid, H2S = hydrosulfuric acid, HF = hydrofluoric acid b) A polyatomic acid (hydrogen and multiple other atoms) Two slight variations: Name Rule: root of anion + -ic acid (when the anion name ends in -ate) Examples: H2SO4 = sulfuric acid, HClO3 = chloric acid, HNO3 = nitric acid Name Rule: root of anion + -ous acid (when the anion name ends in -ite) Examples: H2SO3 = sulfurous acid, HClO2 = chlorous acid, HNO2 = nitrous acid When determining a formula from the name (the reverse process), apply the above rules backwards. Write out the symbols (if its an acid, write an H at the beginning). Always balance the formula by determining the charge on each ion. (Note: the prefixes in molecular compounds tell you how to balance them). Ex.: iron (II) phosphate = Fe3(PO4)2, oxygen difluoride = OF2, hydrobromic acid = HBr. Footnotes: 1 Nearly all of the representative metals have just 1 charge state (a + charge equal to its group number). Exceptions are: Sn2+ & Sn4+, Pb2+ & Pb4+, Bi3+ & Bi5+, Tl+ & Tl3+ 2 Nearly all of the transition metals have multiple charge states (a roman numeral identifies the charge state). Exceptions are: Ag+, Zn2+, Cd2+ (and several other less common ones you don't need to know). 3 Exception: cyanide (CN-) is considered a binary anion since it ends in -ide, so HCN = hydrocyanic acid This nomenclature worksheet has two of every kind of naming rule and exception category on it. Pretend this is a test and then compare your answers with those on the page after it. Keep the next 2 pages synchronized (1st is the questions; 2nd is the answers). Naming compounds from formulas and writing formulas from names - Chapter 5 Write the names for the following chemicals: a) CaS _________________________________ First determine whether each is ionic, (if so, b) H3PO3 _________________________________ whether single or multiple charge states exist), c) NH4Br _________________________________ whether its a molecular compound, or d) SF6 _________________________________ whether its an acid (if so, whether its a e) FeCl3 _________________________________ binary or a polyatomic acid). f) H2S _________________________________ g) Ag2O _________________________________ h) Cr(NO3)3 _________________________________ i) N2H4 _________________________________ j) HBr _________________________________ k) Al(ClO3)3 _________________________________ l) PCl5 _________________________________ m) PbI2 _________________________________ n) Sn(SiO3)2 _________________________________ o) HClO4 _________________________________ Write the proper formulas for each of the following chemicals: a) magnesium sulfide b) diphosphorus pentoxide c) tin (IV) phosphide d) chloric acid e) sodium dichromate f) bismuth (III) nitrate g) hydrocyanic acid h) potassium oxide i) silver sulfide j) dinitrogen trioxide k) lead (II) acetate l) aluminum sulfite m) zinc iodide n) carbon tetrabromide o) phosphorous acid ________________________ Don't forget to balance all formulas. ________________________ ________________________ ________________________ ________________________ (careful) ________________________ ________________________ (careful) ________________________ ________________________ ________________________ ________________________ ________________________ ________________________ ________________________ ________________________ Write the names for the following chemicals: a) CaS calcium sulfide ionic, binary, 1 charge state b) H3PO3 phosphorous acid acid, polyatomic (comes from phosphite anion) c) NH4Br ammonium bromide ionic, polyatomic cation d) SF6 sulfur hexafluoride molecular e) FeCl3 iron (III) choloride ionic, binary, multiple charge states f) H2S hydrosulfuric acid acid, binary (often called H-2-S, a slang name) g) Ag2O silver oxide ionic, binary, 1 charge (a transition metal, but an exception) h) Cr(NO3)3 chromium (III) nitrate ionic, polyatomic, multiple charge states i) N2H4 dinitrogen tetrahydride molecular j) HBr hydrobromic acid acid, binary (often called H-B-R, a slang name) k) Al(ClO3)3 aluminum chlorate ionic, polyatomic, 1 charge state l) PCl5 phosphorous pentachloride molecular m) PbI2 lead (II) iodide ionic, binary, multiple charge states (a rep metal, but exception) n) Sn(SiO3)2 tin (IV) silicate ionic, polyatomic, multiple charge states (rep metal, exception) o) HClO4 acid, polyatomic (comes from perchlorate anion) perchloric acid Write the proper formulas for each of the following chemicals: a) magnesium sulfide MgS binary, ionic, 1 charge state (balance: +2 and -2) b) diphosphorus pentoxide P2O5 molecular (the name tells you how to balance it) c) tin (IV) phosphide Sn3P4 ionic, binary, multiple charges (balance: +4 and -3) d) chloric acid HClO3 acid, polyatomic, chlorate anion (balance: +1 and -1) e) sodium dichromate Na2Cr2O7 ionic, polyatomic, 1 charge state (+1 and -2), di is not a prefix f) bismuth (III) nitrate Bi(NO3)3 ionic, polyatomic, multiple charges (balance: +3 and -1) g) hydrocyanic acid HCN acid, binary (exception), cyanide anion (balance: +1 and -1) h) potassium oxide K2O ionic, binary, 1 charge state (balance: +1 and -2) i) silver sulfide Ag2S ionic, binary, 1 charge state (balance: +1 and -2) exception j) dinitrogen trioxide N2O3 molecular (the name tells you how to balance it) k) lead (II) acetate Pb(C2H3O2)2 ionic, polyatomic, multiple charges (balance: +2 and -1) except l) aluminum sulfite Al2(SO3)3 ionic, polyatomic, 1 charge state (balance: +3 and -2) m) zinc iodide ZnI2 ionic, binary, 1 charge state (balance: +2 and -1) exception n) carbon tetrabromide CBr4 molecular (the name tells you how to balance it) o) phosphorous acid H3PO3 acid, polyatomic, phosphite anion (balance: +1 and -3) Rules and Hints for Balancing Equations - Chapter 7 Always balance the number of atoms within a molecule with subscripts. Always balance the number of molecules within an equation with coefficients. When the number of atoms aren't an exact multiple of each other, use the Least Common Multiple (LCM) method. Until you feel comfortable doing it in your head, make a chart of all atoms. Ex: C H O reactants 1 4 2x2 products 1 2x2 2+2 CH4 + 2 O2 CO2 + 2 H2O You can balance the elements in any order, but certain methods usually (but not always) make it easier to do: balance the metals first, balance the non-metals next, balance all the free elements last. If its not obvious what the coefficient should be, use the algebraic equation method to balance the very last free element. Double check all equations after you are finished balancing them, because frequently balancing one element unintentionally wrecks the balancing of another previously-balanced element. If you have to predict the products of a single-replacement reaction, use the activity table on P. 155. If you have to predict the products of a double-replacement reaction, use the solubility chart on pages 470 and 471 and look for formation of gas, water or unstable product. S = soluble (no precipitate); I = insoluble (a precipitate) Mole Concept - Chapter 6 abbreviation = mol a mole is a quantity of a chemical 1 mole = the molar mass of a substance expressed in the units of grams. 1 mole = the amount of an element that contains exactly 6.022 x 1023 atoms. 1 mole = the amount of a compound that contains exactly 6.022 x 1023 molecules. Avagadro's number = NA = 6.022 x 1023 items / mol. molar mass, molecular weight, atomic weight, formula weight, mass number These terms all mean essentially the same thing, with slight variations, depending upon whether you are referring to an atom, a molecule or an ionic substance. Units are amu (atomic mass units) or grams/mole. 1 mol of He = 4.003 g 1 mol of C = 12.011 g 1 mol of Au = 196.97 g 1 mol of H2 = 2.0158 g 1 mole of CH4 = 16.043 g 1 mole of NH3 = 17.031 g = = = = = = 6.022 x 1023 atoms 6.022 x 1023 atoms 6.022 x 1023 atoms 6.022 x 1023 molecules = 12.044 x 1023 atoms 6.022 x 1023 molecules = 30.110 x 1023 atoms 6.022 x 1023 molecules = 24.088 x 1023 atoms 1 mol of any element contains the same number of atoms (but it does not weigh the same). 1 mol of any compound contains the same number of molecules (but it does not weigh the same). 1 mol of H2O (18.015 g) contains 2 mols of H (2.0158 g) and 1 mol of O (15.999 g) 1 mol of NH3 (17.031 g) contains 1 mol of N (14.007 g) and 3 mols of H (3.024 g) + N2 picture: OO oo oo oo oOo o # of atoms # of molecules # of molecules (x 2) # of molecules (x 10) # of molecules (x 1,000) # of molecules (x NA) # mols molar mass 2 1 2 10 1,000 6 3 6 30 3,000 8 2 4 20 2,000 6.022 x 1023 1 28.014 g 28.014 g 34.062 g 3 H2 chemical equation: = ≠ ≠ ≠ ≠ 23 18.066 x 10 ≠ 3 ≠ 3 x 2.016 g = 6.048 g = = 2 NH3 12.044 x 1023 2 2 x 17.031 g 34.062 g 34.062 g Stoichiometry - Chapter 8 ÷ Avagadro’s number oOo o x molar mass # of atoms (or molecules) # of moles x Avagadro’s number # of grams ÷ molar mass How much does 2.4 mols of Cu weigh? 2.4 mol 63.546 g ! = 152.51 g = 150 g mol How many atoms are there in 5 mols of Fe? 5 mol 6.022 x 10 23 atoms ! = 3.011 x 10 24 atoms = 3 x 10 24 atoms mol How many atoms are there in 3.50 g of Au? 3.50 g ! mole 6.022 x 10 23 atoms ! = 1.07 x 10 22 atoms 196.97 g mol How many molecules are there in 3.50 g of H2O? 3.50 g ! mol 6.022 x 10 23 molecules ! = 1.17 x 10 23 molecules 18.0148 g mol How much will 4.62 x 1025 molecules of H2O weigh? 4.62 x 10 25 molecules ! mol 18.0148 g ! = 1380 g 23 mol 6.022 x 10 molecules How many O atoms are there in 2.00 g of KClO3? 2.00 g KClO 3 ! mol KClO 3 6.022 x 10 23 molecules 3 atoms O ! ! = 2.95 x 10 22 atoms O 122.55 g mol KClO 3 molecule KClO 3
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