Metric Conversions king henry died by drinking chocolate milk k h da b d c m 103 102 101 100 10-1 10-2 10-3 king henry died by drinking chocolate milk k h da base d c m

Metric System Conversions Example: 2.54 cm= _____________ km 0.0000254

TRY THIS: 1000 mg = ______ g 1

TRY THIS: 0.15 m = __________ mm 150

TRY THIS: 0.064 kg = __________ cg 6400

TRY THIS: 89 ds = __________ das 0.89

What is density?   m ÷ ALWAYS REMEMBER UNITS! × D V

Let’s try a density problem together Frank’s paper clip has a mass of 9 g and a volume of 3 mL. What is its density? Density = Mass  Volume Density = 9 g  3 mL = 3 g/mL 9 g = 3 g 3 mL mL m ÷ × D V

Let’s try a density problem together Frank’s eraser has a density of 6 g/mL and a volume of 2 mL. What is its mass? Mass = Density × Volume Mass = 6g/mL × 2mL = 12g 6 g x 2 mL = 12 g mL m ÷ × D V

Let’s try a density problem together Frank’s shot-put has a mass of 500 g and a density of 100 g/mL. What is its volume? Volume = Mass  Density Volume = 500 g  100 g/mL = 5 mL m ÷ × D V

Significant Figures 56,400,000 Is there a decimal? PACIFIC (Present) ATLANTIC (Absent) Start from LEFT & count all #s from first nonzero 0.003100 Start from RIGHT & count all #s from first nonzero 56,400,000 4 sig figs 3 sig figs

You Try! How many sig figs in the following: Examples: a) 1001 km b) 34.00 m c) 129,870 m d) 0.003 km e) 1.003 L f) 6.02 x 1023 atoms g) 20,000 cm h) 0.0023 g Number of Significant Figures: a) 4 b) 4 c) 5 d) 1 e) 4 f) 3 g) 1 h) 2

CALCULATIONS WITH SIG FIGS Summary Multiplying or dividing: round to the measurement with the smallest number of significant figures. 2.6 cm x 3.78 cm = 9.828 cm2 Adding or subtracting: round the answer to the smallest number of decimal places. 165.5 cm + 8 cm + 4.37 cm = 177.87 cm = 9.8 cm2 = 178 cm

PARTS OF THE ATOM Nucleus: Contains protons and neutrons VERY tiny Contains all the atom’s mass Electron Cloud: Contains electrons Makes up the atom’s volume No mass

Isotope Naming  

Electron Configurations 7p

Electron Configurations Electrons fill sublevels in the order on the chart. Read it like a book – from left to right. Every sublevel to the left and above is filled. Boron (B) 1s22s22p1 Oxygen (O) 1s22s22p4 7p

Electron Configurations Electrons fill sublevels in the order on the chart. Read it like a book – from left to right. Every sublevel to the left and above is filled. Silicon (Si) 1s22s22p63s23p2 Gallium (Ga) 1s22s22p63s23p64s23d104p1 7p

2A: Alkaline Earth Metals Periodic Table ROWS: Periods COLUMNS: Families or Groups 8A: Noble Gases 1A: Alkali Metals 7A: Halogens 2A: Alkaline Earth Metals

Trends in Electronegativity Ability of an atom to attract electrons in another atom * Fluorine has the highest electronegativity, Noble gases have ZERO electronegativity

Trends in Ionization Energy The energy required to remove an electron from an atom

Trends in Atomic Size Atomic Size The distance between the nucleus and the outer edge of the electron cloud

Ionic Bonds – electrons transferred Metals lose electrons and Nonmetals gain electrons to form an ionic bond. Properties of Ionic Compounds Crystal lattice structure High melting points Conducts electricity when melted or dissolved in water

Predicting Ionic Charges Group 1A: Lose 1 electron to form 1+ ions H+ Li+ Na+ K+ Rb+

Predicting Ionic Charges Group 2A: Loses 2 electrons to form 2+ ions Be2+ Mg2+ Ca2+ Sr2+ Ba2+

Predicting Ionic Charges Loses 3 electrons to form 3+ ions Group 3A: B3+ Al3+ Ga3+

Predicting Ionic Charges Neither! Group 4A elements rarely form ions EXCEPTION: Sn and Pb!! Treat like transition metals Do they lose 4 electrons or gain 4 electrons? Group 4A:

Predicting Ionic Charges Nitride Gains 3 electrons to form 3- ions Group 5A: P3- Phosphide As3- Arsenide

Predicting Ionic Charges Oxide Gains 2 electrons to form 2- ions Group 6A: S2- Sulfide Se2- Selenide

Predicting Ionic Charges Gains 1 electron to form 1- ions Group 7A: F1- Fluoride Br1- Bromide Cl1- Chloride I1- Iodide

Predicting Ionic Charges Stable noble gases do not form ions! Group 8A:

Covalent Bonds – electrons shared Bond between two nonmetals. Properties of Covalent Compounds Lower melting points Does not conduct electricity when dissolved in water

Metallic Bonds – “sea” of electrons Bond between two metals. Bond is the attraction between electrons and positive nucleus. Properties of Metallic Compounds Malleable (pounded into shapes) Ductile (pulled into wires) Conducts electricity as a solid.

NAMING COMPOUNDS Use roman numerals for transition metals IONIC COMPOUNDS: Name the CATION then the ANION Use roman numerals for transition metals Example: Cu(NO3)2 copper (II) nitrate COVALENT COMPOUNDS (molecules): Use prefixes to match the subscript. Second atom name ends in “ide” Example: N2O4 dinitrogen tetroxide

WRITING FORMULAS Example: iron (II) chloride Fe2+ Cl- Fe 1 Cl 2 FeCl2 IONIC COMPOUNDS: USE THE CROSS RULE: Example: iron (II) chloride Fe2+ Cl- Fe 1 Cl 2 FeCl2 COVALENT COMPOUNDS (molecules): Use prefixes to identify the subscripts. Example: trichloro tetrafluoride Cl3F4

Lewis Structure of Molecules Add up all the valence electrons. This is the number of dots in the final structure. Place least electronegative element in center. (Never H) Place two electrons between central and outer atoms Fill up outer atom octets. Fill up central atom octet. Make double or triple bonds if necessary so all atoms meet the octet rule. Br2 2(7) = 14

Lewis Structure of Molecules Add up all the valence electrons. This is the number of dots in the final structure. Place least electronegative element in center. (Never H) Place two electrons between central and outer atoms Fill up outer atom octets. Fill up central atom octet. Make double or triple bonds if necessary so all atoms meet the octet rule. H2O 6 + 2(1) = 8

Lewis Structure of Molecules Add up all the valence electrons. This is the number of dots in the final structure. Place least electronegative element in center. (Never H) Place two electrons between central and outer atoms Fill up outer atom octets. Fill up central atom octet. Make double or triple bonds if necessary so all atoms meet the octet rule. CO2 4 + 2(6) = 16

Balancing Reactions Balance reactions so that the same number of atoms are on both sides. ONLY change coefficients, NOT subscripts. _____C3H8 + ____O2  ____CO2 + ____H2O ____ Pb(NO3)2 + ____ HCl  ____ PbCl2 + ____ HNO3 Balance in the following order Polyatomic ions (as a group, only if they appear on both sides) Metals Nonmetals Hydrogen 5.Oxygen

Calculating Percent Composition Example Determine the percent composition of each element in Mg(NO3)2 Determine the contribution of each element Molar mass On a per mol basis

Mole Conversions 1 mole = 6.02  1023 particles 1 mole = _______ g *particles could be molecules, ions, atoms, formula units 1 mole = _______ g *1 mole equals the molar mass of the atom or compound 1 mole = 22.4 L * for gases only at STP (Standard Temperature (0˚C and Standard Pressure (1 atm))

Mole Conversions a. What is the number of moles of CaS in 120 g? 1 mole =72.2 g CaS = 1.7 moles 120 g CaS 1 mole 72.2 g CaS b. What is the mass in grams of 1.81 x 1023 molecules of CO2? 1 mole =6.02  1023 particles, 1 mole =44.0 g CO2 = 13.2 g 1.81 x 1023 molecules CO2 1 mole 72.2 g CO2 6.02 x 1023 molecules

Mole Conversions c. How many molecules of CO2 are in 0.50 moles? 1 mole = 6.02  1023 particles = 3.01x1023 molecules 0.50 moles CO2 1 mole 6.02 x 1023 molecules d. How many liters do 7.87×1023 molecules of H2S occupy at STP? 1 mole =6.02  1023 particles, 1 mole =22.4 L at STP = 29.3 L 7.87 x 1023 molecules CO2 1 mole 22.4 L 6.02 x 1023 molecules

Mole Conversions e. What is the number of liters that 27 g of oxygen gas occupies at STP? 1 mole =32.0 g O2, 1 mole =22.4 L at STP = 18.9 L 27 g O2 1 mole 22.4 L 32 g O2

Stoichiometry Calculations Zn(s) + 2 HCl(aq)  ZnCl2(aq) + H2(g) 38a. How many moles of H2 if 4 moles of HCl react? CONVERSION FACTOR: mole ratio: ___ mole _____ = ___ mole ______ 2 mol HCl = 1 mol H2 4 mol HCl 1 mol H2 = 2 mol H2 2 mol HCl

Stoichiometry Calculations Zn(s) + 2 HCl(aq)  ZnCl2(aq) + H2(g) 38b. How many grams of Zn if 3 moles of ZnCl2 are formed? CONVERSION FACTORS: mole ratio: ___ mole _____ = ___ mole ______ molar mass: 1 mole ____ = _____ g ______ 1 mol Zn = 1 mol ZnCl2 1 mol Zn = 65.34 g Zn 3 mol ZnCl2 1 mol Zn 65.34 g Zn = 196.2 g Zn 1 mol ZnCl2

Stoichiometry Calculations Zn(s) + 2 HCl(aq)  ZnCl2(aq) + H2(g) 38c. How many grams of HCl if 6.87 g Zn react? CONVERSION FACTORS: mole ratio: ___ mole _____ = ___ mole ______ molar mass: 1 mole ____ = _____ g ______ 1 mol Zn = 2 mol HCl 1 mol Zn = 65.34 g Zn 1 mol HCl = 36.45 g HCl 6.87 g Zn 1 mol Zn 2 mol HCl 36.45 g HCl = 7.7 g HCl 65.34 g Zn 1 mol HCl

Stoichiometry Calculations Mg + 2 HNO3  Mg(NO3)2 + H2 39a. If 40 g Mg react, how many grams H2 form? CONVERSION FACTORS: mole ratio: ___ mole _____ = ___ mole ______ molar mass: 1 mole ____ = _____ g ______ 1 mol Mg = 1 mol H2 1 mol Mg = 24.3 g Zn 1 mol H2 = 2.0 g H2 40 g Mg 1 mol Mg 1 mol H2 2.0 g H2 = 3.3 g H2 24.3 g Mg

Stoichiometry Calculations Mg + 2 HNO3  Mg(NO3)2 + H2 39b. If 1.7 g H2 was ACTUALLY produced, what was the percent yield?   Actual Yield: Given in problem (1.7 g H2) Theoretical Yield: Calculated in part a (3.3 g H2)  

Stoichiometry Calculations Mg + 2 HCl  ZnCl2 + H2 40a. If 40 g Zn and 40 g HCl react, how many grams H2 form? This is a limiting reactant problem. Do 2 calculations. CONVERSION FACTORS: mole ratio: ___ mole _____ = ___ mole ______ molar mass: 1 mole ____ = _____ g ______ First Calculation: 1 mol Zn = 1 mol H2 1 mol Zn = 65.4 g Zn 1 mol H2 = 2.0 g H2 40 g Zn 1 mol Zn 1 mol H2 2.0 g H2 = 1.22 g H2 65.4 g Zn

Stoichiometry Calculations Mg + 2 HCl  ZnCl2 + H2 40a. If 40 g Zn and 40 g HCl react, how many grams H2 form? This is a limiting reactant problem. Do 2 calculations. CONVERSION FACTORS: mole ratio: ___ mole _____ = ___ mole ______ molar mass: 1 mole ____ = _____ g ______ Second Calculation: 2 mol HCl = 1 mol H2 1 mol HCl = 35.5 g HCl 1 mol H2 = 2.0 g H2 40 g HCl 1 mol HCl 1 mol H2 2.0 g H2 = 1.10 g H2 36.5 g HCl

Stoichiometry Calculations Mg + 2 HCl  ZnCl2 + H2 40b. If 40 g Zn and 40 g HCl react, how many grams H2 form? What is the limiting reactant? First Calculation (Zn is reactant): Produced 1.22 g H2. Second Calculation (HCl is reactant): Produced 1.10 g H2. HCl produced the LEAST amount of product so it is the limiting reactant. You can only produce 1.10 g H2.