Chemistry Chapter 9 Chemical Formulas and Chemical Compounds Heart cell rhythm depends on the opening and closing of a complex series of valves on the cell membrane, called ion channels. Some valves let certain ions ike potassium (K+) flow out, others let different ions like sodium (Na+) flow in. There are also pumps that actively move ions one direction or another.

Nomenclature - Humor “Ferrous Wheel” Fe = iron (Latin = ferrum) Fe 2+ = lower oxidation state = ferrous Iron II Fe 3+ = higher oxidation state = ferric Iron III BaNa 2 “BaNaNa” Fe 2+ What weapon can you make from the elements nickel, potassium and iron? A KNiFe

IonsIons Cation: A positive ionCation: A positive ion Mg 2+, NH 4 +Mg 2+, NH 4 + Anion: A negative ionAnion: A negative ion Cl , SO 4 2 Cl , SO 4 2  Ionic Bonding: Force of attraction between oppositely charged ions.Ionic Bonding: Force of attraction between oppositely charged ions.

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

Predicting Ionic Charges Group 2: Loses 2 electrons to form 2+ ions Be 2+ Mg 2+ Ca 2+ Sr 2+ Ba 2+

Predicting Ionic Charges Group 13: Loses 3 Loses 3 electrons to form 3+ ions B 3+ Al 3+ Ga 3+

Predicting Ionic Charges Group 14: Lose 4 Lose 4 electrons or gain 4 electrons?

Predicting Ionic Charges Group 15: Gains 3 Gains 3 electrons to form 3- ions N 3- P 3- As 3- Nitride Phosphide Arsenide

Predicting Ionic Charges Group 16: Gains 2 Gains 2 electrons to form 2- ions O 2- S 2- Se 2- Oxide Sulfide Selenide

Predicting Ionic Charges Ionic Group 17: Gains 1 Gains 1 electron to form 1- ions F 1- Cl 1- Br 1- Fluoride Chloride Bromide I 1- Iodide

Predicting Ionic Charges Group 18: Stable Noble gases do not form ions! Stable Noble gases do not form ions!

Predicting Ionic Charges Groups : Many transition elements Many transition elements have more than one possible oxidation state. have more than one possible oxidation state. Iron(II) = Fe 2+ Iron(III) = Fe 3+

Metal Cations Type I Group A metalsType I Group A metals –Metals that can only have one possible charge –Determine charge by position on the Periodic Table Type II Transitional Metals Group BType II Transitional Metals Group B –Metals that can have more than one possible charge –Determine metal cation’s charge from the charge on anion (algebraic sumation) –Know the following: Pb +2 Lead II Sn +2 Tin II Pb +2 Lead II Sn +2 Tin II Pb +4 Lead IV Sn +4 Tin IV Pb +4 Lead IV Sn +4 Tin IV Cu +1 Copper I Fe +2 Iron II Cu +1 Copper I Fe +2 Iron II Cu +2 Copper II Fe +3 Iron III Cu +2 Copper II Fe +3 Iron III Memorize these

Predicting Ionic Charges Groups : Some transition elements Some transition elements have only one possible oxidation state. have only one possible oxidation state. Zinc = Zn 2+ Silver = Ag + Remember these Aluminium = Al +3

Writing Binary Ionic Formulas Ionic Nomenclature Tutorial Ionic Nomenclature Tutorial Ionic Nomenclature Tutorial Example: Aluminum sulfide 1. Write the formulas for the cation and anion, including CHARGES! Al 3+ S Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Not balanced! 23 Simulation Al 2 S 3

Naming Binary Ionic Compounds Compounds Naming Binary Ionic Compounds Compounds 1. Cation first, then anion1. Cation first, then anion 2. Monatomic cation = name of the element2. Monatomic cation = name of the element Ca 2+ = calcium ionCa 2+ = calcium ion 3. Monatomic anion = root + -ide3. Monatomic anion = root + -ide Cl  = chlorideCl  = chloride CaCl 2 = calcium chlorideCaCl 2 = calcium chloride

Writing Ionic Compound Formulas Example: Barium nitrate 1. Write the formulas for the cation and anion, including CHARGES! Ba 2+ NO Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Not balanced! ( ) 2 Ba(NO 3 ) 2

Writing Ionic Compound Formulas Example: Ammonium sulfate 1. Write the formulas for the cation and anion, including CHARGES! NH 4 + SO Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Not balanced! ( ) 2 (NH 4 ) 2 SO 4

Writing Ionic Compound Formulas Example: Magnesium carbonate 1. Write the formulas for the cation and anion, including CHARGES! Mg 2+ CO Check to see if charges are balanced. They are balanced! MgCO 3

Writing Ionic Compound Formulas Example: Zinc hydroxide 1. Write the formulas for the cation and anion, including CHARGES! Zn 2+ OH - 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Not balanced! ( ) 2 Zn(OH) 2

Writing Ionic Compound Formulas Example: Aluminum phosphate 1. Write the formulas for the cation and anion, including CHARGES! Al 3+ PO Check to see if charges are balanced. They ARE balanced! AlPO 4

Naming Ternary Ionic Compounds (continued) - some metal forms more than one cation- some metal forms more than one cation -use Roman numeral in name-use Roman numeral in name PbCl 2PbCl 2 Pb 2+ is cationPb 2+ is cation PbCl 2 = lead(II) chloridePbCl 2 = lead(II) chloride Metals with multiple oxidation states

Assigning Oxidation Numbers H +1 with nonmetals H -1 with metals (hydride) O -2 with nonmetals ( most common) O +2 with halogens O -1 in peroxide ion O 2 -2

Writing Ionic Binary Formulas w/ Transitional Elements Example: Iron(III) chloride 1. Write the formulas for the cation and anion, including CHARGES! Fe 3+ Cl - 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Not balanced! 3 ________ FeCl

Naming Covalent Binary Compounds - Compounds between two nonmetals- Compounds between two nonmetals -First element in the formula is named first.-First element in the formula is named first.element -Second element is named as if it were an anion (-ide).-Second element is named as if it were an anion (-ide). -Use prefixes-Use prefixes -Only use mono on second element --Only use mono on second element - P 2 O 5 = CO 2 = CO = N 2 O = diphosphorus pentoxide carbon dioxide carbon monoxide dinitrogen monoxide

Properties of Acids   Acids taste sour   Acids effect indicators   Blue litmus turns red   Methyl orange turns red   Acids have a pH lower than 7   Acids are proton (hydrogen ion, H + ) donors   Acids react with active metals, produce H 2   Acids react with carbonates   Acids neutralize bases

Acids you must know: Strong Acids Weak Acids Hydrochloric acid, HCl Nitric acid, HNO 3 Sulfuric acid, H 2 SO 4 Phosphoric acid, H 3 PO 4 Acetic acid, HC 2 H 3 O 2

Naming Acids Binary Acids:2 elements only Contains Hydrogen plus a monatomic ion HCl H + (Hydro) + Cl - (chlorine becomes –ic ) Hydrochloric Acid Ternary (oxyacid) Acid: 3 or more elements Contains Hydrogen plus a polyatomic ion Phosphate (PO 4 -3 ) H 3 PO 4 Phosphoric acid Phosphite (PO 3 -3 ) H 3 PO 3 Phosphorous acid

Sulfuric Acid  Highest volume production of any chemical in the U.S.  Used in the production of paper  Used in production of fertilizers  Used in petroleum refining

. Sulfuric acid is used as a drying agent to chemically remove water from many substances. If poured on sugar crystals (C 11 H 22 O 11 ), the acid removes eleven molecules of water for every molecule of sucrose. After dehydrating the sugar, all you have left is a brittle, spongy black mass of carbon! If sulfuric acid gets on your skin, it immediately begins to take water out of the molecules in the skin. This is what causes an acid burn. sugar

Nitric Acid Nitric Acid Used in the production of fertilizersUsed in the production of fertilizers Used in the production of explosivesUsed in the production of explosives Nitric acid is a volatile acid – its reactive components evaporate easilyNitric acid is a volatile acid – its reactive components evaporate easily Stains proteins (including skin!)Stains proteins (including skin!)

Hydrochloric Acid Used in the pickling of steelUsed in the pickling of steel Used to purify magnesium from sea waterUsed to purify magnesium from sea water Part of gastric juice, it aids in the digestion of proteinPart of gastric juice, it aids in the digestion of protein Sold commercially as “Muriatic acid”Sold commercially as “Muriatic acid”

Phosphoric Acid oA flavoring agent in sodas oUsed in the manufacture of detergents oUsed in the manufacture of fertilizers oNot a common laboratory reagent

Acetic Acid  Used in the manufacture of plastics  Used in making pharmaceuticals  Acetic acid is the acid present in vinegar

Acids are Proton Donors Monoprotic acidsDiprotic acidsTriprotic acids HCl HC2H3O2HC2H3O2 HNO 3 H 2 SO 4 H 2 CO 3 H 3 PO 4

Predicting type of substance Predicting type of substance Nomenclature Practice Nomenclature PracticeNomenclature PracticeNomenclature Practice

Calculating Formula Mass Formula Calculate the formula mass of magnesium carbonate, MgCO g g + 3(16.00 g) = g

Calculating Percentage Composition Calculate the percentage composition of magnesium carbonate, MgCO 3. From previous slide: g g + 3(16.00 g) = g

Formulas  molecular formula = (empirical formula) n [n = integer]  molecular formula = C 6 H 6 = (CH) 6  empirical formula = CH Empirical formula: the lowest whole number ratio of atoms in a compound. Molecular formula: the true number of atoms of each element in the formula of a compound.

Formulas (continued) Formulas for ionic compounds (formula units) are ALWAYS empirical (lowest whole number ratio). Examples: NaClMgCl 2 Al 2 (SO 4 ) 3 K 2 CO 3

Formulas (continued) Formulas for molecular compounds MIGHT be empirical (lowest whole number ratio). Molecular: H2OH2O C 6 H 12 O 6 C 12 H 22 O 11 Empirical: H2OH2O CH 2 O C 12 H 22 O 11

Empirical Formula Determination 1.Base calculation on 100 grams of compound. 2.Determine moles of each element in 100 grams of compound. 3.Divide each value of moles by the smallest of the values. 4.Multiply each number by an integer to obtain all whole numbers.

Empirical Formula Determination Adipic acid contains 49.32% C, 43.84% O, and 6.85% H by mass. What is the empirical formula of adipic acid?

Empirical Formula Determination (part 2) Divide each value of moles by the smallest of the values. Carbon: Hydrogen: Oxygen:

Empirical Formula Determination (part 3) Multiply each number by an integer to obtain all whole numbers. Carbon: 1.50 Hydrogen: 2.50 Oxygen: 1.00 x Empirical formula: C3H5O2C3H5O2

Finding the Molecular Formula The empirical formula for adipic acid is C 3 H 5 O 2. The molecular mass of adipic acid is 146 g/mol. What is the molecular formula of adipic acid? 1. Find the formula mass of C 3 H 5 O 2 3(12.01 g) + 5(1.01) + 2(16.00) = g

Finding the Molecular Formula The empirical formula for adipic acid is C 3 H 5 O 2. The molecular mass of adipic acid is 146 g/mol. What is the molecular formula of adipic acid? 3(12.01 g) + 5(1.01) + 2(16.00) = g 2. Divide the molecular mass by the mass given by the emipirical formula.

Finding the Molecular Formula The empirical formula for adipic acid is C 3 H 5 O 2. The molecular mass of adipic acid is 146 g/mol. What is the molecular formula of adipic acid? 3(12.01 g) + 5(1.01) + 2(16.00) = g 3. Multiply the empirical formula by this number to get the molecular formula. (C 3 H 5 O 2 ) x 2 = C 6 H 10 O 4

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