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.