AP Chemistry Introductory Material
Chemical FoundationsChapter 1 Observations Hypotheses Predictions • Scientific Method Theory Or Model Predictions Experiment Modify Theory
Scientific Method • You are given a computer and asked to make a graph. After booting the computer, opening excel and entering data, the screen goes blank. • Oh Gees! Now What!
Units of Measurement • Expect you to know • pico to giga • And be able to convert • Units used in science • Kilograms, meters, seconds, kelvins, amps, moles
Significant Figures • There is more than one convention! • AP Chemistry allows for some variation • If you are within one sig fig, it is OK • We will follow this • Rules are on Pg 23 of your book • We will use these for every calculation • You lose a point for incorrect sig figs on test
corrected 6.4 Calculations 12.11 18.0 1.013 31.123 31.1 • Adding and subtraction • Answer has the same number of decimal places as the least precise measurement. • Multiplication and Division • Answer has the same number of significant figures • as the least precise measurement • 4.56 x 1.4 = 6.38 • pH • The number to the left of the decimal is the exponent • The number to the right of the decimal contains the • correct number of sig figs. • pH = 7.07 has 2 sig figs
Dimensional Analysis • Do I really have to? • No, but it will cost you extra work explaining yourself • Units written out in Dim Analysis are self explanatory • It’s way easier! • Way, way easier!! • Just Do it!
Mercury poisoning is a debilitating disease that is often fatal. In the human body, mercury reacts with essential enzymes leading to irreversible inactivity of these enzymes. If the amount of mercury in a polluted lake is 00.4000 micrograms Hg per milliliter, what is the total mass in kilograms of mercury in the lake. The lake has a surface area of 0100. mi2 and an average depth of 20.1 ft. (5280. ft in a mile, 12 in in a foot, 2.54 cm in an inch, 106 micrograms in a gram)
Classification of Matter • What is a mixture? • Name two types • How can we separate hetero? • Homo? • If I say something is a pure substance, what does that mean? • What is the difference between an element and a compound? • What is an element made up of?
It’s the Law • Explain the following laws: • Conservation of Mass • Definite proportion • Multiple proportion • Name four parts of Dalton’s Atomic Theory • Atoms • All atoms of same element are identical • Same compound always has same elements in same proportions • Atoms themselves do not change in chemical reactions
Famous Atomic ExperimentsDescribe the Experiment • JJ Thompson and CRT’s • Used CRT to determine charge to mass ratio • Discovered electron • Rutherford’s Gold Foil • Used alpha particles and gold foil • Discovered a dense, positive nucleus • Millakan’s Oil Droplet • Discovered the charge of an electron • Calculated the mass of an electron with JJ’s reults
Modern Theory • Subatomic particles are? • Electron, neutron and proton • Nucleus is composed of ? • Neutron and proton • Electrons are in “clouds” • What does that mean?
F -1 19 9 Symbol How many protons? How many neutrons? How many electrons?
Periodic TableDescribe the following: • Period • Metals • Non-metals • Semi-metals • Alkali Metals • Alkali Earth Metals • Transition Metals • Halogens • Noble gases
La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Modern periodic table 1 2 13 14 15 16 17 18 I A II A III A IV A V A VI A VIIA 0 He H 1 2 3 4 5 6 7 Li Be B C N O F Ne 3 4 5 6 7 8 9 10 11 12 III B IVB V B VIB VIIB VIII B IB IIB 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 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe * Cs Ba Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn + Fr Ra Lr * +
He B C N O F Ne Si P S Cl Ar Ge As Se Br Kr At Rn Metals H Li Be Na Mg Al K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te Xe I * Cs Ba Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po + Fr Ra Lr La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb * Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Ac +
Nonmetals He H 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 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe * Cs Ba Ly Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn + Fr Ra Lr Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb * La Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Ac +
Semimetals or Metalloids 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 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te Xe I * Cs Ba Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn + Fr Ra Lr * La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No +
Bonds and Stuff Explain the following • Ion • Cation and anion • Ionic Bond • Covalent Bond • Molecule • Formula Unit • Chemical Formula • Structural Formula
Ions and Ionic Compounds Important: note that there are no easily identified NaCl molecules in the ionic lattice. Therefore, we cannot use molecular formulas to describe ionic substances.
Naming Compounds • Memorize all polyatomic ions pg 63 and how to determine the rest • Memorize names of elements • s block, p block = all • Transition metals • Need to know common metals • Charges on Al+3, Zn+2, Ag+1, Cd+2
Ions • Ions are charged particles formed by the transfer of electrons between elements or combinations of elements. • Cation - a positively charged ion. • Mg Mg2+ + 2e- • Anion - a negatively charged ion. • F2 + 2e- 2F-
Writing Formulas All compounds are electrically neutral. The sum of the positive and negative charges must add up to zero. O2- Al3+ 2 3 Use subscripts to indicate how many of each ion is used. Al2O3
Naming inorganic compounds When an element forms only one compound with a given anion. • name the cation • name the anion using the ending (-ide) for monatomic ions • NaCl sodium chloride • MgBr2 magnesium bromide • Al2O3 aluminum oxide • K3N potassium nitride
Naming ionic compounds • Many metals form more than one compound with some anions. • For these, Roman numerals are used in the name to indicate the charge on the metal. • Cu1+ +O2- = Cu2O • copper(I) oxide copper(I) oxide • Cu2+ +O2- = CuO • copper(II) oxide copper(II) oxide
Naming ionic compounds • Since the charge of some metal ions can vary, look at everything else first. • What ever is left is the charge on the metal! • FeBr3 • The three bromides are each 1- so iron must be 3+ for the compound to have zero net charge. • Iron (III) bromide
Examples iron (II) chloride iron (III) chloride tin (II) sulfide tin (IV) sulfide silver chloride zinc sulfide FeCl2 FeCl3 SnS SnS2 AgCl ZnS Note: Some transition metals have only one oxidation state, so Roman numbers are omitted.
Metals with multiple charges • Transition metals. • Here it is easier to list some of the common elements that only have a single oxidation state. • All Group 3B are 3+ • Zn and Cd are 2+ • Ag is 1+
Oxidation numbers and the P.T. • Some observed trends in compounds. • Metals have positive oxidation numbers. • Transition metals typically have more than one oxidation number. • Nonmetals and semimetals have both positive and negative oxidation numbers. • No element exists in a compound with an oxidation number greater than +8. • The most negative oxidation numbers equals the group number - 8
Li +1 Be +2 Na +1 Mg +2 K +1 Ca +2 Rb +1 Sr +2 Cs +1 Ba +2 Fr +1 Ra +2 B +3 C +4 -2 -4 N +5 +4 +3 +2 +1 -3 O -1 -2 F -1 Ne H +1 He Al +3 Si +4 -4 P +5 +3 -3 S +6 +4 +2 -2 Cl +7 +5 +3 +1 -1 Ar Sc 3+ Ti +4 +3 +2 V +5 +4 +3 +2 Cr +6 +3 +2 Mn +7 +6 +4 +3 +2 Fe +3 +2 Co +3 +2 Ni +2 Cu +2 +1 Zn +2 Ga +3 Ge +4 -4 As 5+ 3+ 3- Se 6+ 4+ 2- Br +5 +1 -1 Kr +4 +2 Y +3 Zr +4 Nb +5 +4 Mo +6 +4 +3 Tc +7 +6 +4 Ru +8 +6 +4 +3 Rh +4 +3 +2 Pd +4 +2 Ag +1 Cd +2 In +3 Sn +4 +2 Sb +5 +3 -3 Te +6 +4 -2 I +7 +5 +1 -1 Xe +6 +4 +2 Lu +3 Hf +4 Ta +5 W +6 +4 Re +7 +6 +4 Os +8 +6 Ir +4 +3 Pt +4 +2 Au +3 +1 Hg +2 +1 Tl +3 +1 Pb +4 +2 Bi +5 +3 Po +2 At -1 Rn Lr +3 Common oxidation numbers
Polyatomic ions • A special class of ions where a group of atoms tend to stay together. • NH4+ ammonium • NO3- nitrate • SO42- sulfate • OH- hydroxide • O22- peroxide • Your book contains a more complete list.
Polyatomic ions • For compounds that contain 1 or 2 polyatomic ions, base the formulas upon the given ion name(s). • ammonium chloride NH4Cl • sodium hydroxide NaOH • potassium permanganate KMnO4 • ammonium sulfate (NH4)2SO4
Naming Inorganic Compounds Names and Formulas of Ionic Compounds Polyatomic anions containing oxygen with more than two members in the series are named as follows (in order of decreasing oxygen): per- …. -ate ClO41- …. -ate ClO31- …. -ite ClO21- hypo- …. -ite ClO1-
Oxidation number and nomenclature • Polyatomic anions containing oxygen rely on a modification of the name of the other element to indicate the oxidation number. • Anions • per ________ate • ________ate • ________ite • hypo ________ite Increased #oxygen and Oxidation number
Oxidation number and nomenclature • Examples • Cl oxidation • number Formula Name • +7 NaClO4 sodium perchlorate • +5 NaClO3 sodium chlorate • +3 NaClO2 sodium chlorite • +1 NaClO sodium hypochlorite • -1 NaCl sodium chloride • Usually, the overall charges of all ions for a nonmetal are the same. Sometimes the -ates and -ites have a different charge than the -ide ions.
-ate has 4 Oxygens La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Polyatomic Ions -ate has 3 Oxygens 1 2 13 14 15 16 17 18 I A II A III A IV A VA VI A VIIA 0 H He -ate & -ite charges usually = -ide charge 1 2 3 4 5 6 7 Li Be B C N O F Ne 3 4 5 6 7 8 9 10 11 12 III B IVB V B VIB VIIB VIII B IB IIB Na Mg Al Si P S Cl Ar Slivka’s Square K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe * Cs Ba Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn + Fr Ra Lr * +
Polyatomic Ions “ate” 4 Oxygens .. Inside Slivka’s Square ex: SO42- sulfate 3 Oxygens .. Borders the outside of the square ex: NO31- nitrate
Polyatomic Ions “ite” 1 less Oxygen compared to the -ate ex: ClO21- chlorite SO32- sulfite
Polyatomic Ions “per” root name “ate” has 1 more O than the “ate”ex: IO41-periodate “hypo” root name “ite” has 2 less O than the “ate” ex: ClO1- hypochlorite
Polyatomic Ions “Per”-“ate” 1 more O - “ate” - “ite” 1 less O “hypo”-“ite” 2 less O (also notice oxidation # of nonmetal changes)
La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Polyatomic Ions Group B Elements follow Group A patterns 1 2 18 I A II A VIIIA CrO42- chromate MnO41- permanganate 13 14 15 16 17 H He III A IV A VA VI A VIIA 1 2 3 4 5 6 7 Li Be B C N O F Ne 3 4 5 6 7 8 9 10 11 12 III B IVB V B VIB VIIB VIII B IB IIB 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 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe * Cs Ba Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn + Fr Ra Lr * +
Other Methods of Naming - Latin • For ionic compounds containing a metal and a nonmetal, the Latin root word for the metal is sometimes used with an -ous or -ic suffix. • The -ous suffix indicates a lower oxidation state, -ic a higher one. • Ex. ferrous = Fe2+ • ferric = Fe3+
Latin Root Words plumbous = Pb2+ plumbic = Pb4+ aurous = Au1+ auric = Au3+ cuprous = Cu1+ cupric = Cu2+ stannous = Sn2+ stannic = Sn4+ Note that there is no pattern between the -ous and -ic suffixes and the actual charge of the ions.
Naming Covalent Compounds • What is the difference between SO32-and SO3 • polyatomic ion vs. neutral compound sulfite ionvs. sulfur (VI) oxide
Naming Covalent Compounds • Some nonmetals can have more than one positive oxidation state when they share electrons to form molecules called covalent compounds. Therefore Roman numbers must be used. SCl4 sulfur (IV) chloride SCl sulfur (VI) chloride CO carbon (II) oxide CO2 carbon (IV) oxide
Naming Inorganic Compounds • Names and Formulas of Binary Molecular Compounds • Binary molecular compounds are composed of two nonmetallic elements. • The element with the positive oxidation number (the one closest to the lower left corner on the periodic table) is usually written first. Exception: NH3. • Greek prefixes are used to indicate the number of atoms in the molecule(subscripts). • PCl5 is phosphorus pentachloride
Naming Inorganic Compounds Names and Formulas of Binary Molecular Compounds Roman numerals can be used to indicate the positive oxidation number, but sometimes prefixes more accurately describe the actual composition of the molecule. Example: sulfur (V) fluoride exists as disulfur decafluoride molecules. F F F F S S F F F F F F
Other Methods of Naming molecules • For binary molecular compounds composed of two nonmetals, prefixes are sometimes used to indicate the number of atoms of each element present. Common prefixes mono = 1 di = 2 tri = 3 tetra = 4 penta = 5 hexa = 6 hepta = 7 octa = 8 deca = 10
Other Methods of Naming molecules • name elements in the formula. • use prefixes to indicate how many atoms there are of each type. • N2O5 • CO2 • CO • CCl4 • dinitrogen pentoxide • carbon dioxide • carbon monoxide • carbon tetrachloride • The rule may be modified to improve how a name sounds. • Example - use monoxide not monooxide.
Other Naming -Acids • Acidsare substances that produce H+ ions in water solutions (aqueous). • The names of acids are related to the names of the anions to which H+ is bonded: • -ide becomes hydro-….-icacid • H2S is hydrosulfuric acid • -ate becomes -ic acid • H3PO4 is phosphoric acid • -ite becomes -ous acid • HNO2 is nitrous acid