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Metric Conversions king henry died by drinking chocolate milk
k h da b d c m king henry died by drinking chocolate milk k h da base d c m
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Metric System Conversions
Example: cm= _____________ km
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TRY THIS: 1000 mg = ______ g 1
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TRY THIS: 0.15 m = __________ mm 150
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TRY THIS: kg = __________ cg 6400
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TRY THIS: 89 ds = __________ das 0.89
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What is density? m ÷ ALWAYS REMEMBER UNITS! × D V
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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
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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
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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
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Significant Figures 56,400,000 Is there a decimal? PACIFIC (Present)
ATLANTIC (Absent) Start from LEFT & count all #s from first nonzero Start from RIGHT & count all #s from first nonzero 56,400,000 4 sig figs 3 sig figs
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You Try! How many sig figs in the following: Examples: a) 1001 km
b) m c) 129,870 m d) km e) L f) 6.02 x 1023 atoms g) 20,000 cm h) g Number of Significant Figures: a) 4 b) 4 c) 5 d) 1 e) 4 f) 3 g) 1 h) 2
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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 = cm2 Adding or subtracting: round the answer to the smallest number of decimal places. 165.5 cm + 8 cm cm = cm = 9.8 cm2 = 178 cm
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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
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Isotope Naming
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Electron Configurations
7p
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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
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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
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2A: Alkaline Earth Metals
Periodic Table ROWS: Periods COLUMNS: Families or Groups 8A: Noble Gases 1A: Alkali Metals 7A: Halogens 2A: Alkaline Earth Metals
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Trends in Electronegativity
Ability of an atom to attract electrons in another atom * Fluorine has the highest electronegativity, Noble gases have ZERO electronegativity
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Trends in Ionization Energy
The energy required to remove an electron from an atom
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Trends in Atomic Size Atomic Size The distance between the nucleus and the outer edge of the electron cloud
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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
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Predicting Ionic Charges
Group 1A: Lose 1 electron to form 1+ ions H+ Li+ Na+ K+ Rb+
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Predicting Ionic Charges
Group 2A: Loses 2 electrons to form 2+ ions Be2+ Mg2+ Ca2+ Sr2+ Ba2+
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Predicting Ionic Charges
Loses 3 electrons to form 3+ ions Group 3A: B3+ Al3+ Ga3+
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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:
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Predicting Ionic Charges
Nitride Gains 3 electrons to form 3- ions Group 5A: P3- Phosphide As3- Arsenide
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Predicting Ionic Charges
Oxide Gains 2 electrons to form 2- ions Group 6A: S2- Sulfide Se2- Selenide
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Predicting Ionic Charges
Gains 1 electron to form 1- ions Group 7A: F1- Fluoride Br1- Bromide Cl1- Chloride I1- Iodide
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Predicting Ionic Charges
Stable noble gases do not form ions! Group 8A:
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Covalent Bonds – electrons shared
Bond between two nonmetals. Properties of Covalent Compounds Lower melting points Does not conduct electricity when dissolved in water
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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.
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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
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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
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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
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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
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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
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Balancing Reactions Balance reactions so that the same number of atoms are on both sides. ONLY change coefficients, NOT subscripts. _____C3H ____O2 ____CO ____H2O ____ Pb(NO3) ____ HCl ____ PbCl ____ HNO3 Balance in the following order Polyatomic ions (as a group, only if they appear on both sides) Metals Nonmetals Hydrogen 5.Oxygen
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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
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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))
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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 molecules CO2 1 mole 72.2 g CO2 6.02 x molecules
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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 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 molecules CO2 1 mole 22.4 L 6.02 x molecules
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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
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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
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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 = g Zn 3 mol ZnCl2 1 mol Zn 65.34 g Zn = g Zn 1 mol ZnCl2
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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 = g Zn 1 mol HCl = 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
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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
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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)
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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 = g H2 65.4 g Zn
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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 = g H2 36.5 g HCl
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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.
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