Chemical Nomenclature

Transcription

1 Chamras CHEMISTRY 110 LECTURE NOTES EXAM 2 Materials: Chp s. 5 (in part), 6, 7 IUPAC: Chemical Nomenclature Types of Naming: a) Ionic Compounds b) Binary Molecular Compounds c) Acids d) Hydrates How to tell these types apart by just looking at the formula? Formula Indicator Example Ionic Molecular Acid Hydrate First, A brief review on the Periodic Table of Elements: The Periodic Table: Lists all the elements that are so far known to us. Most of the elements are naturally occurring but some are human-made. Metals and non-metals are separated by the zigzag line starting at B(boron), and ending At(astatine). With the exception of aluminum (Al), all the elements touching the metal-non-metal separation line are called metalloids or semi-metals. Metals lose electrons (become cations) and non-metals gain electrons (become anions) when ionized. Metals of Groups 1, 2, and 13 assume charges of +1, +2, and +3 respectively, when ionized. 1

2 Non-metals of groups 15, 16, and 17, assume charges of 3, 2, and 1 respectively, when ionized. When formulating an ionic compound, the Principle of Neutrality applies. Review on Ionic Charges: H Li Be Simple Cations with Fixed Charges Na M g Al K Ca Zn Rb Sr Ag Cd Cs Ba Fr Ra H Simple Anions N O F P S Cl Br I Nomenclature rule for Mono-atomic (simple) Cations with Fixed Charge: Template: Name of Neutral Element + ion Examples: Nomenclature rule for Mono-atomic (simple) Anions: Template: Rootname for element + ide Examples: ***Cations with Variable Charges: 2

3 Simple Cations with Variable Charges Cr M n Fe Co Ni Cu As Sn Au Hg Pb Sb Bi Nomenclature rule for Mono-atomic (simple) Anions: Two methods: 1) Name for element + (Charge for cation indicated in Roman numeral form). Example: 2) Latin name of cation + ous or ic + Name of the anion Example: Need to Know: Element Name Lower Charge Ion Name Higher Charge Ion Name Cr chromium Cr 2+ chromous Cr 3+ chromic Mn manganese Mn 2+ manganous Mn 3+ manganic Fe ferrum Fe 2+ ferrous Fe 3+ ferric Co cobalt Co 2+ cobaltous Co 3+ cobaltic Ni nickel Ni 2+ nickelous Ni 3+ nickelic Cu cuprum Cu + cuprous Cu 2+ cupric Au aurum Au + aurous Au 3+ auric Hg mercury Hg 2+ 2 [Hg + ] mercurous Hg 2+ mercuric (hydrargyrum) Sn stannum Sn 2+ stannous Sn 4+ stannic Pb plumbum Pb 2+ plumbous Pb 4+ plumbic As arsenicum As 3+ arsenous As 5+ arsenic Sb antimonium Sb 3+ antimonious Sb 5+ antimonic (stibium) Bi bisemutum Bi 3+ bisemutous Bi 5+ bisemutic 3

4 Template: name for cation name for anion Examples: Practice problems for writing names and formulas (in both directions): Complete the following Table: Chemical Formula IUPAC Name Chem. Formula IUPAC Name Na 3 P potassium chloride CaO aurous nitride FeN (two ways) barium fluoride manganic oxide Fe 3 N 2 (two ways) HgCl 2 Al 2 S 3 MgBr 2 SnO 2 chromium (III) phosphide iron(ii) iodide cuprous nitride silver oxide aluminum bromide copper(i) phosphide Mono-atomic (Simple) ions Versus Polyatomic Ions Examples: List of Polyatomic Ions to Know for CHEM110 Cations: 4

5 NH 4 + ammonium ion Hg 2 2+ mercury(i) or mercurous ion Anions: Charge: 1- Charge: 2- Charge 3- H 2 PO 4 dihydrogen phosphate HPO 4 2 monohydrogen phosphate PO 4 3 phosphate H 2 PO 3 dihydrogen phosphite HPO 3 2 monohydrogen phosphite PO 3 3 phosphite HCO 3 2 HSO 4 2 SO 3 NO 3 2 bicarbonate CO 3 (hydrogen carbonate) 2 bisulfate SO 4 (hydrogen sulfate) 2 bisulfite SO 3 (hydrogen sulfite) 2 nitrate O 2 carbonate sulfate sulfite peroxide NO 2 nitrite CrO 4 2 chromate C 2 H 3 O 2 acetate Cr 2 O 7 2 BrO 4 perbromate C 2 O 4 2 dichromate oxalate BrO 3 BrO 2 BrO CN OCN SCN MnO 4 OH bromate bromite hypobromite cyanide cyanate thiocyanate permanganate hydroxide Practice problems for writing names and formulas: Complete the following table: 5

6 Chemical Formula IUPAC Name Chem. Formula IUPAC Name Na 3 PO 4 potassium chlorate CaO 2 aurous nitrite Fe(NO 2 ) 2 (two ways) barium perbromate manganic peroxide Fe(NO 3 ) 3 (two ways) mercury (I) phosphite iron(ii) hypoiodite Hg 2 Cl 2 Al 2 (SO 4 ) 3 Mg(BrO 2 ) 2 Sn(CO 3 ) 2 cuprous sulfate silver oxalate aluminum acetate copper(ii) permanganate What are binary molecular compounds? 6

7 Template: # prefix + name of the first element # prefix + name of the second ion Example: Exception: If there is only one of the first element as written in the formula, the prefix mono is absent. Latin Number Prefixes: # Prefix Meaning # Prefix Meaning mono- 1 hexa- 6 di- 2 hepta- 7 tri- 3 octa- 8 tetra- 4 nona- 9 penta- 5 deca- 10 Practice problems for naming binary molecular compounds: Complete the following table: IUPAC Name dichlorine pentaphosphide Chemical Formula CO 2 dinitrogen monoxide N 2 O 4 NO Definition for acid: 7

8 There are two methods of naming acids (based on the type): a) Binary Acids: Template: hydro + rootname for non-h element + ic acid HBr(aq) à b) Oxy-Acids: rootname for non-o, non-h element + ic acid (for anions ending in ate ) ous acid (for anions ending in ite ) Examples: HBrO 3 (aq) à HBrO 2 (aq) à ***If the formula of the acid is displayed without the (aq) solution indicator, then name it as an ionic compound (name the hydrogen as a cation) uniformly, regardless of the type being binary or oxy-acid. Examples: HBr à HBrO 3 à HBrO 2 à Practice problems for naming acids: Complete the following table: 8

9 IUPAC Name hydrobromic acid hydrogen nitrite hypoiodous acid hydrogen sulfide HClO 4 (aq) HClO 3 HNO 2 (aq) H 3 PO 4 Chemical Formula Definition for hydrates: Everyday examples of hydrates: Nomenclature Exercise: Complete the following naming tables: Name Formula Name Formula barium nitrate H 2 SO 4 (aq) dichlorine pentoxide AlI 3 mercurous peroxide Hg 3 (PO 4 ) 2 bromic acid AuOH. 6H 2 O ammonium sulfite Ag 2 O 2 hydrogen perchlorate HBrO 2 sulfur trioxide Mn(NO 2 ) 3 ferric bicarbonate trihyrdate K 2 O hydroiodic acid NO periodic acid HCl Nomenclature Chart: 9

10 Chapter 6: Chemical Composition To account for the amount of a chemical substance: 10

11 grams or amu 1 amu = x g Remember: Atomic mass. 29 Cu atom of copper = amu => 63.55amu x (1.66 x g) = 1.05 x g 1 amu Example: Determine the mass of 3 aluminum atoms: Problem with practical measurement: Grains of sugar? Individual count of eggs? Grains of rice? Any solution for the problem? Solution: The MOLE 11

12 Avogadro s Number: x particles 1 Mole of Particles *Remember: Particles = Advantages: How? Mass of a proton: 1 amu = x g ( x g) x ( x ) = 1g A few examples of Avogadro s number of objects: 1. A computer counting atoms at 10 million atoms a second would take 2 billion years to count one mole of atoms. 2. If one mole of marbles were spread over the surface of the Earth, our planed would be covered by a 50-mile-thick layer of marbles. 3. A glass of water, which is about 10 moles of water, contains more water molecules than there are grains of sand in the Sahara desert. Some interesting sites: Cu

13 1 atom of copper = amu => 63.55amu x (1.66 x g) = 1.05 x g 1 amu 1 mole of copper = x copper atoms = g!!!! Average Atomic Mass à Average Molar Mass Molar Mass: Sample Problems: Two types of Conversions: 1. moles particles USE: Avogadro s Number 2. moles grams USE: Molar Mass from the Periodic Table Examples: a) Calculate the mass of 3.44 moles of aluminum: b) How many moles of carbon will 55.4 grams of carbon be? c) How many atoms of iron would 5.33 x 10 2 moles of iron be? d) How many moles of gold would 1.00 x atoms of gold be? 13

14 e) How many grams of silver would 33.3 x atoms of silver be? f) How many atoms of mercury would have a mass of grams? What is in a formula? Example: N 2 O 5 à g) Calculate the molar mass of water: h) Calculate the molar mass of nitrogen gas: i) Calculate the molar mass of ammonium phosphate: j) How many atoms of oxygen are there in 44.0 grams of water? k) How many molecules of nitrogen can be generated using the nitrogen present in 3.0 milligrams of iron(iii) nitrate? Percent Composition of Compounds (Analytical Chemistry) Based on the percentage by mass. 14

15 *Remember: The general concept of Percentage Example: NaCl Calculate the Percentage by mass of sodium in sodium chloride: Calculate the Percentage by mass of carbon in ethanol (Formula = C 2 H 6 O): Definition: Empirical Formula (Analytical Chemistry) 15

16 Sample problem: The results of combustion analysis on g of an unknown substance indicate that it is made of 1.201g of carbon, 0.800g of oxygen, and g of hydrogen. Determine the empirical formula for this compound: *Variation: The results of combustion analysis on an unknown substance indicate that it is made of % carbon, % oxygen, and % hydrogen. Determine the empirical formula for this compound: Determination of Molecular Formula (Analytical Chemistry) Need Molar Mass. 16

17 Example: a) The results of combustion analysis on g of an unknown substance indicate that it is made of 1.201g of carbon, 0.800g of oxygen, and g of hydrogen. Determine the empirical formula for this compound: b) If the molar mass of this compound is 92.00g.mol 1, determine its molecular formula: Challenge Problem (To be solved after CHP.7): Problem: grams of an unknown organic compound containing carbon, hydrogen, and oxygen was subjected to a combustion reaction with excess oxygen, as shown in the reaction below: 17

18 C x H y O z + no 2 (g) xco 2 (g) + y H 2 O(g) 2 As a result, grams of carbon dioxide and grams of water formed. Determine the empirical formula for this unknown organic compound: Chapter 7: Chemical Reactions & Types What Is A Chemical Reaction? 18

19 Evidences for Chemical Reactions: 1. Formation of solid 2. Formation of Gas 3. Evolution or Absorption of Heat (Thermal Energy) 4. Color Change Chemical Equations: A Short Hand Method to Describe Chemical Reactions Example: Solid sodium metal reacts with water and forms aqueous sodium hydroxide and hydrogen gas. Writing Chemical Equations: Reactant Side Product Side Reaction Arrow States Relative Amounts: Law of Conservation of Mass Balancing Chemical Equations (Balancing by inspection) Solutions: Definition: 19

20 Components of Solution: Examples of Solutions: SOLVENT SOLUTE Example Solubility: Some Conditions Affecting Solubility: 1. Temperature 2. Polarity: (like dissolves like) Ionic Polar Slightly polar non polar Dissolution Process (behavior) in Water: a) For SOLUBLE Ionic Compounds: 20

21 b) For POLAR Molecular Compounds: c) For Strong Acids & Bases: d) For Weak Acids & Bases: ***Dissociation: Lecture Demonstration: Aq. Solution Name Solute Formula * Solute Type Solution Inventory ** Light Int. % Dissociation sodium chloride hydrochloric acid sodium hydroxide ammonium hydroxide acetic acid sugar tap water deionized water None (H 2 O only) *Solute Type: Soluble ionic, strong acid, strong base, weak acid, weak base, polar molecular. ** Light intensity: Bright, dim, none. Types of Chemical Reactions 1. Synthesis (Combination) 2. Drcomposition 21

22 3. Single Replacement 4. Double Displacement 5. Combustion More Details on Chem. Reactions: 1. Single Replacement: How to predict 22

23 a) The products? Remember the general reaction form (p.22): b) If a reaction will happen or not? Using: Common Metals Activity Series Examples: a) A piece of lead is placed in an aqueous solution of cupric nitrate: CM CI NI b) Powdered magnesium is added to a solution of tin(iv) bromide: CM CI NI c) A gold nugget is placed in brine: (What is brine??) CM CI NI 2. Double Displacement: How to predict a) The products? Remember the general reaction form (p.22): 23

24 b) If a reaction will happen or not? Check for formation of: If at least one of the 5 is present, then there will be a reaction. Formation of a solid: How to Predict the Solubility Behavior of a Product? Use SOLUBILITY RULES Solubility Rules for Ionic Compounds: Behavior Compounds Containing the Ions of Exception(s) Soluble + Group 1 metals & NH 4 None Soluble - NO 3 None Soluble Cl -, Br -, I - Ag +, Hg 2+ 2, Pb 2+ Soluble 2- SO 4 Ba 2+, Pb 2+, Ca 2+ Insoluble S 2-, CO , PO 4 + Group 1 metals & NH 4 Insoluble OH - Group 1 metals & NH + 4, Ca +, Ba 2+, Sr 2+ Example: Label the following ionic compounds as soluble or insoluble. Na 3 PO 4 : AgBr: HgI 2 : PbCl 4 : Hg 2 Cl 2 : BaCO 3 : Ca(OH) 2 : Fe(OH) 3 : Li 2 S: Formation of weak acid + base: Why weak and not strong? 24

25 Acid & Base Solubility: *Remember: Definition for Acids: Strong Acids: Weak Acids: Definition for Bases: Strong Bases: Weak Bases: List of Strong Acids: (7) HCl(aq), HBr(aq), HI(aq), H 2 SO 4 (aq), HNO 3 (aq), HClO 4 (aq), HClO 3 (aq) Weak Acids: List of Strong Bases: (8) LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH) 2, Sr(OH) 2, Ba(OH) 2 Weak Base: (1) NH 4 OH Examples: Write the complete and balanced molecular equation, and predict whether a reaction will occur if: a) A solution of aluminum sulfate is mixed with a solution of barium nitrate. CM 25

26 CI NI b) A solution of calcium acetate is mixed with hydrochloric acid: CM CI NI c) A solution of lithium carbonate is mixed with a solution of potassium iodide: CM CI NI d) Hydroiodic acid is mixed with calcium hydroxide: CM CI NI e) A solution of calcium hydroxide is mixed with a solution of ammonium phosphate: CM CI NI 3 Ways to Write Chemical Equations: 1. Complete Molecular Equation: 26

27 2. Complete Ionic Equation: 3. Net Ionic Equation: *Practice on P. 23 and p