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Unit 4 Naming
Naming Binary Ionic Compounds
• In an ionic compound, the cation always comes first followed by the anion• Cation = positive charge • Anion = negative charge
• When naming binary (meaning two elements) ionic compounds1. The cation is named its complete element name (H would be
hydrogen)2. The anion is named its root name plus “ide”
Last vowel in the root is typically dropped
Common anion roots include …
• H – Hydro; hydride
• F – Fluoro; fluoride
• Cl – Chloro; chloride
• Br – Bromo; bromide
• I – Iodo; iodide
• O – Oxy; oxide
• S – Sulfa; sulfide
• N – Nitro; nitride
• P – Phospho; phosphide
ExamplesNaCl CaBr2 Rb2O
CsF AlCl3 LiH
Na2O CaS Sr3N2
BeS MgO KCl
Naming Ionic Compounds w/ Polyatomic Ions • Same rules as naming binary ionic compounds except
polyatomic ions are always given their full name • You do not take the element root and add ide
Examples:
Na2CO3 AlPO4
NH4Cl BaSO4
KMnO4 NaNO3
“I have … , who has … ?” • I will start with a particular
molecular formula • Whoever has the name of
the compound will state that they have it (by stating the name of the compound)
• They will then ask who has the molecular formula on their card
• The next person will continue in similar fashion
• Mr. Norris says NaCl
Sodium Chloride
KBr
Potassium Bromide
NaCN
Sodium cyanide
CaO
Boiling Points of Various Molecules
Phosphate Phosphate w/ Resonance
• Explain the observation that the P – O bond in phosphate is somewhere between the bond length for a P – O single and double bond.
Naming Covalent Compounds • Between two non-metals • Sharing electrons
• Because we can have millions of combinations of two elements for various covalent compounds we need a way to indicate the number of a particular element in a molecule
• We can have C2H2, C2H4, C2H6, and many more combinations of just carbon and hydrogen
Greek Prefixes
1. Mono 2. Di 3. Tri 4. Tetra5. Penta6. Hexa7. Hepta8. Octa9. Nona10. Deca
The Rules
• CO2 Carbon dioxide • CO Carbon monoxide
First Element is Named: Number + element name (If there is only one do not use mono)
Second Element is Named: Number + element root name + ide (Do need to use mono if there is just one)
• State the number of an element using the Greek prefixes
Examples• SiO2
• Silicon dioxide
• B2I6
• Diboron hexaiodide
• Si2F6
• Disilicon hexafluoride • SiO• Silicon monoxide
• Note “a” and “o” vowels are not doubled up • IE monoxide not monooxide
Practice
• IO2
• C2Br6
• N4O9
• P4Se3
• C2H4
• NO
• NH3
• CH4
“I have … , who has … ?“ • I will start with a particular
molecular formula • Whoever has the name of
the compound will state that they have it (by stating the name of the compound)
• They will then ask who has the molecular formula on their card
• The next person will continue in similar fashion
• Mr. Norris says CO
Carbon monoxide
CO2
Carbon dioxide
NH3
Nitrogen trihydride
NO
Naming Ionic Compounds with Transition Metals • Transition Metals middle block of the periodic table• Can have multiple oxidation numbers • Pb and Sn as well
Naming Ionic Compounds with Transition Metals • Normal rules for naming ionic compounds with one exception • Must indicate the oxidation number of the transition metal
with a roman numeral in ( ) • FeO Iron (II) oxide • Cu3N Copper (I) Nitride
• Key added step: • Determining the oxidation number of the transition metal
Determining Oxidation Number of a Transition Metal• We know overall charge must be 0 in an ionic compound
Example: Fe2O3
• How many atoms cation (Fe) • How many atoms anion (O) • What is the charge/oxidation # of the anion (O) • What is the charge/oxidation # cation (Fe)
Steps
1. Gather Information• Atoms cation • Atoms anion • Charge/oxidation # anion
2. Set up algebraic equation # anion(charge) + # cation(charge) = 0
3. Solve for missing charge/oxidation #
4. Check
Examples
• ZrCl2
• Fe2O
• MnS3
Examples
• Zn3(PO4)2
• SnI2
• PbBr4
Practice • One whiteboard and marker per partner pair • Work with your partner to name the compound • When you have and have checked your answer, raise your
board
1. PdBr3
2. CrS2
3. CoN4. Cu3N
5. HgCrO4
Practice • Individually, on your own, name the compound • When you have and have checked your answer wait until I tell
you to switch boards • You will switch boards with your neighbor at your table and
check their work and tell them either where they messed up or that you agree
Example: FeO
1. NiF2. FeP3. CoS4. Fe(CN)2
5. Co2(SO4)3
Ionic Bingo • 5 minutes to work on translating the names of ionic molecules
on your card to their molecular formulas • 15 minutes of Bingo • Winners Bonus Points on Quiz Weds.
• I will say molecular formula twice and write on board • Do not call out answers • False Bingos = Cannot Win
Acids • Acids are special types of compounds that contain hydrogen
atoms and when dissolved in water increase the concentration of hydrogen ions (H+)
Acid Basics • In an acid, H acts like a cation (H+) and always comes first in
the molecular formula • Seeing an H at the start of a molecular formula allows you to
identify a compound as an acid • We name acids bases on the anion bound to H
Naming Binary Acids • Acids with two elements (H and something else) • Rules:
hydro – element root name – ic acid
HF – hydrofluoric acid fluoride; dropping ide and adding ic acid
H3N – hydronitric acid
HI – hydroiodic acid
HCl HBr
Naming Acids w/ Polyatomic Ions • Majority of acids • Rules: • Look at ending of polyatomic ion • Replace “ate” with “ic acid”• Replace “ite” with “ous acid”
• HClO3 – Chloric acid • ClO3 – chlorate
• HClO2 – Chlorous acid • ClO2 – chlorite
Examples/Practice
HC2H3O2
H2CO3
HBrO3
HClO4
HIO3
H2CrO4
Exceptions: P and S • Root names adjusted • H3PO4 – • Phosphoric acid not phosphic acid
• H3PO3 – • Phosphorous acid not phosphous acid
• H3P – • Hydrophosphoric acid not hydrophosphic acid
• H2SO4 – • Sulfuric acid not sulfic acid
• H2SO3 – • Sulfurous acid not sulfous acid
• H2S – • Hydrosulfuric acid not hydrosulfic acid
Molar Mass Intro • Just like cooking, when performing chemical reactions it is
important to know what amount of starting material will yield a certain amount of product • IE 3 cups of flour can make 2 dozen cookies
• In chemistry we call our starting material the reactant • Reactant • Starting material in a chemical reaction
Molar Mass Intro • In Chemistry we will typically measure our reactant in either
moles or grams• To interchange between the two and to perform other
calculations we will need to know how to determine the molar mass of a substance
• Molar Mass – mass of one mole of a substance• Usually expressed in grams/mole (g/mol)
Molar Mass of Elements • We get the mass of one mole of an element by looking at the
atomic weight of an element and rounding to the nearest tenth • Atomic weight – typically found on the bottom of an element’s
box on the periodic table
Examples:
H _____ O _____ Cl _____Na _____ N _____ Br _____
Molar Mass Examples
Determine the molar mass of carbonic acid, H2CO3
LiCl CO2
NH4OH Fe2(CrO4)3
Whiteboard Practice • NaCl• CaCO3
• (NH4)2S
% Composition • One minute to pick something about your group that a % of
you will be, examples include: • % of individuals with birthdays in June or July • % of 16 year olds in the class • % of APUSH students in the class
• You will then calculate the % so that you know what it is (rounding to the nearest tenth)
• I will then try to guess what the % is, my score will be the difference between my guess and the actual number • Low score = good score
% Composition = Part/whole
Examples • Determine the % composition of Na in NaCl
• Determine the % composition of O in CaCO3
• Determine the % composition by of oxygen, O, in the following compounds:
Fe(CO3)2
Al(IO3)3
Whiteboard Practice • AgCl• H2PO4
• C3H6
• Zn(NO3)2
Molecular Formula
• The chemical symbols and subscripts that represent the exact number of atoms in a given molecule• What we have been working with • Examples:
• CO2
• C2H2
• Al2(SO4)3 • MgO
Empirical Formula
• The chemical symbols and subscripts that represent the lowest, whole number ratio of elements in a molecule • Think reduced • Example: CH is the empirical formula of C6H6
• Important for covalent molecules but not ionic ones or acids • Ionic compounds and acids combine in the simplest way
possible to balance charge• The molecular and empirical formula for all ionic compounds and
acids will be the same
Molecular Formula Empirical FormulaWater
Methane(carbon tetrahydride)
Sulfuric Acid
Benzene(hexacarbon hexahydride)
Calcium oxide
Glucose(C6H12O6)
Molecular Formula
Empirical Formula
Name
H3P
ZnCO3
CaCl2
P4O10
H2S
C4H8
AlN
Molecular Formula from Molar Mass and Empirical Formula • A molecule has an empirical formula of C2H3O and a molar
mass of 172g/mol, what is the molecular formula of the molecule?
Steps 1. Determine the molar mass of the
empirical formula2. Compare (i.e. divide) the given
molar mass (molecular formula) by the mass of the empirical formula • Large number divided by small
number
3. Your quotient is the factor by which your empirical formula has been reduced, therefore you multiply each subscript in the empirical formula by the quotient
4. Check your answer by calculating the molar mass of the molecular formula
What is the molecular formula of a compound with an empirical formula of CH2 and a molecular formula of 56.0g/mol?
Practice • An organic molecule has an empirical formula of CH and a
molar mass of 78g/mol. What is the molecular formula of the molecule?
• A molecule has an empirical formula of CH3 and a molar mass of 45g/mol. What is the molecular formula?
Molecular Formula from % Composition and Molar Mass • Nicotine is 74.1% carbon, 8.6% hydrogen, and 17.3% nitrogen
by mass, and has a molar mass of 162g/mol. What is the molecular formula of nicotine?
Steps
1. Convert each percent to decimal form
2. Multiply each decimal by the molar mass of the molecule
3. Divide each of your products by the molar mass of the appropriate element
4. Your quotients give the amount of each element in the molecular formula
Determine the molecular formula of a compound that contains 36.5% sodium, 25.4% sulfur, 38.1% oxygen and has a molar mass of 126g/mol.
Practice • A biologically important molecule contains 40.0% carbon,
6.7% hydrogen, 53.3% oxygen by mass. Determine the molecular formula if the molecule has a molar mass of 180g/mol.
Challenge • Determine the empirical formula of a compound that contains
58.8% barium, 13.75% sulfur, and 27.45% oxygen by mass.