Transcript Document
Science 10 Chemistry Unit A Study Complete homework Review Success Significant Digits • Any digit from 1-9 is significant • Sandwich zeros are significant – E.g. 2.04, 1005.002 • Trailing zeros are significant – E.g. 6.3800, 12 000 • Leading zeros are not significant – E.g. 0.0065 • counted objects and constants are not included • (+ or -) : – round to the lowest number of decimal places 2.35g + 16.77g + 12.1g = 31.22g 31.2g • (x or ): – round to the lowest number of sig digs 100 g 53.29 g/mol = 1.8765 mol 1.88 mol WHMIS •Workplace Hazardous Materials Information System •WHMIS provides guidelines for handling, storage and disposal of reactive materials Know your WHIMIS SYMBOLS! compressed gas poisonous and infectious material causing immediate and serious toxic effects corrosive poisonous and infectious causing other toxic effects flammable and combustible Dangerously active material oxidizing material biohazardous infectious material Matter • It is anything that has mass and occupies space • Has properties which describe the substance • Two types of properties – physical – chemical • It can be classified as being a mixture or a pure substance Substance (Matter) Pure Substance Mixtures Physical Properties • Describe its appearance or features you can measure: density color boiling point melting point Chemical Properties • Describes how it reacts with others substances • It cannot be tested without destroying the substance E.g. combustion, rusting, decomposition reactions Classification of Matter Substance (Matter) Pure Substance Elements Metals Metalloids Non-metals Mixtures Compounds Ionic Heterogeneous Colloids Homogeneous Suspension Alloys Molecular Solutions 1. Mixtures • Are created when 2 or more substances combine • There are 2 types: Heterogeneous Homogenous A. Heterogeneous Mixture • 2 or more phases are visible, or two or more substances are visible • E.g. chicken soup, pulpy orange juice • There are two types: Suspension Colloid Suspension • Is a mixture in which the components are in different states • E.g. Mud (water & sand) Colloids • A mixture in which the components can’t be easily separated • E.g. Milk or salad dressing B. Homogeneous Mixture • A mixture of 2 or more substances that appear as one….( uniform properties) • E.g. kool-aid, coffee, air • There are 2 types: Alloys Solutions Alloys • A homogenous mixture of 2 or more metals • E.g. brass – copper-zinc Solutions • A mixture where you can not see the different parts 2. Pure Substances • The composition does not change • They can be: Elements Compounds A. Elements • Cannot be broken down further • contains only one type of atom • E.g. Gold • Have 3 categories: Metals Nonmetals metalloids Metals • Are: ductile (can be stretched into wire) lustrous (shiny) silver conductors malleable found to the left of the staircase line make up approx. 80% of the elements Non-Metals • Are: non-ductile dull Sulphur non-conductors brittle found to the right of the staircase line make up approx. 20% of the elements Metalloids • Are elements that have properties of both metals and non-metals arsenic E.g. carbon – dull, conducts silicon – lustrous, nonconductor silicon B. Compounds • Are two or more elements bonded together in fixed proportions • E.g. H2O , C6H12O6 The Periodic Table • It was developed by Dmitri Mendeleev in the mid 1800’s Atomic Number Ionic Charge Element Symbol Atomic Mass Element Name • It follows certain rules (patterns) called the “Periodic Law” • It is arranged into groups (families) and periods Period • Are the horizontal rows on the periodic table Period 1 - 2 elements Period 2 - 8 elements Period 3 - 8 elements Period 4 - 18 elements Period 5 - 18 elements Period 6 – 32 elements Period 7 – 32 elements Groups (Families) • Vertical columns • Have similar properties (behave in a similar manner) • The number indicates the # of electrons in the last energy level • Have 2 numbering systems : a) Arabic #’s (1 -> 18) b) Roman numerals & letters (IIA ,VIIB) Group IA • Alkali Metals (E.g. Li, Na, K) • most reactive metals • never found in pure form in nature • all have one electron in the last energy level Group IIA • Alkaline Earths (E.g. Mg, Ca, Ba) • very reactive metals • all have 2 electrons in the last energy level Group VII A • Halogens E.g. (Cl2, Br2, ) • most reactive non-metals • all are diatomic elements E.g.( F2, I2, At2 ) • are one electron short of a full energy level Group VIII A • Are Noble Gases • non-reactive elements (inert gases) • all have full energy levels Series • Are at the bottom of the periodic table • Lanthanum (Lathanides) are rare earth metals located 57-71 • Actinium (Actinides) Are located 89 to 103 Transition Elements • Belong to Group B • Are located in the middle of the table magnetic elements are found here Trends of Transition Metals • metals: – get more reactive as you move (R L) and – The most reactive metal is FRANCIUM • Non-metals : – get more reactive as you move (L R) and – this excludes noble gases Atomic Structure • Describes what an atom is made up of • http://www.youtube.com/watch?v=07yDiEL e83Y&feature=related • A Theory was proposed by Dalton in 1808 Dalton’s Theory 1. All matter is composed of tiny, indivisible particles called atoms. 2. Atoms of an element have identical properties 3. Atoms of different elements have different properties 4. Atoms of two or more elements can combine in constant ratio to form new substances. Know this: Page 22 Textbook J.J Thompson: 1897 • credited with discovery of electrons • “raisin bun” model or “plum pudding” model • atom is a sphere which is positive, with negative electrons embedded in it like raisins in a bun • most of the mass is associated with the positive charge Ernest Rutherford: 1911 • atoms have a nucleus which is positive and has most of the mass • most of the atom is empty space occupied by the moving negatively charged electrons • proposed the existence of protons http://www.learnerstv.com/animation/animati on.php?ani=121&cat=chemistry Neils Bohr: 1913 • electrons move in circular orbits around the nucleus • cannot exist between orbits James Chadwick: 1932 • showed that the nucleus must contain heavy neutral particles to account for all of the atom’s mass (neutrons) Schrodinger/de Broglie: 1930 • quantum mechanical model • electrons have distinct energy levels • exact locations of electrons are not defined, but the probable location in a region of space can be predicted Atoms • Are the smallest part of an element which retains the chemical and physical properties of an element. • They are neutral • It is made up of 3 sub-atomic particles: –Protons –Neutrons –Electrons Protons (P+) • Are large positively charged particle in the atom’s nucleus • They make up 99% of the mass of the atom • the number of protons determines the atomic number • E.g. Cu has 29 protons… atomic number =29 Neutrons (N0) • Are large particles in the atom’s nucleus • They hold the nucleus together • They have no charge Electrons (e-) • Are the smallest particle in an atom • They have a negative charge • Are located outside the nucleus of the atom • They take up most of the space • They are arranged in energy levels • The # of electrons in each level is : • Level # of e• 1 2 • 2 8 • 3 8 • 4 18 You MUST MEMORIZE THIS!!!!! Atomic Number • Is the # of protons in an atom E.g. oxygen: atomic # = 8 it has 8 protons Atomic Number Ionic Charge Element Symbol Atomic Mass Element Name Mass Number • Also called the atomic mass • its the sum of the protons and neutrons (These are averages) Atomic Number Ionic Charge Element Symbol Atomic Mass Element Name • E.g. Lithium Atomic Number Atomic Mass 3 6.9 (so it has 3 Neutrons) (round it) • Try: Mercury Atomic Number Atomic Mass ___ (so it has _ Neutrons) ___ (round it) • Try: Chlorine Atomic Number Atomic Mass ___ (so it has _ Neutrons) ___ (round it) Finding The Number of Neutrons • Use the Formula: Neutrons = Atomic Mass – Protons • E.g. Oxygen Mass = Protons = ____ ____ Neutrons = Atomic Mass – Protons Neutrons = _____ - ____ Neutrons = _____ Try the Following • E.g. Calcium Mass = ____ Protons = ____ • Neutrons = Atomic Mass – Protons • Neutrons = _____ - ____ • Neutrons = _____ Isotopes • Have a different atomic mass • They have a different number of neutrons…. but same number of protons • E.g. Copper has 35 neutrons ..but an isotope of copper can have 36 Isotope Notation x A z A = symbol x = mass # (p+ + n°) z = atomic # (p+) Try copper – 64 (together) Isotope Notation x z A A = symbol x = mass # z = atomic # (#p+ + n°) (#p+) copper - 64 __ Cu __ Try copper - 62 # p+ = ____ #n° = ___ - ___ =___ # e- = ____ # p+ = _____ #n° = _____ # e- = _____ Try the Following • Write the isotope notation for the following: Cobalt - 61 Cobalt – 60 EELR - Electron Energy Level Representations • It is a diagram that shows the following: – The Nucleus – Energy Levels – Valence electrons • Energy Levels: show the number of electrons in each level number of levels = the period # • Valence Electrons: Are electrons in the last energy level It is the group # E.g. Sodium # p+ = # e- = #n° = - atomic # - mass # ___ ___ ____ ____ ____ - ____ = _____ (round) __ e__ e- ____ ____ e- __ ep+ = ___ n° = ___ Level 1 = 2 Level 2 = 8 Level 3 = 8 Level 4 = 18 E.g. Sodium # p+ = # e- = #n° = - atomic # - mass # 11 11 22.99 - 11 = 11.99 1 e8 e- 11 22.99 12 11 e- 2 ep+ = 11 n° = 12 Level 1 = 2 Level 2 = 8 Level 3 = 8 Level 4 = 18 Krypton # p+ = # e- = #n° = - atomic # - mass # _____ _____ ___ ___ ___ - ____ = ____ round ___ ___ e___ e___ e___ ep+ = ___ n° = ___ ____ e- Level 1 = 2 Level 2 = 8 Level 3 = 8 Level 4 = 18 Krypton # p+ = # e- = #n° = - atomic # - mass # 36 83.80 36 36 83.80 - 36 = 47.80 48 18 e8 e8 e2 ep+ = 36 n° = 48 36 e- Level 1 = 2 Level 2 = 8 Level 3 = 8 Level 4 = 18 Assignment Draw an EELR for each of the following atoms (a) (c) (e) (f) berylium chlorine calcium magnesium Ions • Are atoms or group of atoms that have: – become electrically charged – gained or lost electrons to be isoelectronic with a noble gas (same configuration) • They can be: – Monatomic – Polyatomic Their outer orbital is filled A. Monatomic Ions • Are made of one element • Can be: – Cations – Anions Cations • Are positively charged • Are METALS • lose electrons …….to obtain a stable electron configuration (like a noble gas) • E.g. Sodium ( Na+1 ) • • • • E.g. Sodium ion Losses 1 electron It tries to have the same configuration as Neon Na+1 has 10 electrons • • • • Try: Calcium Ion Losses _____ electron(s) It tries to have the same configuration as _____ Ca 2+ has ________ electrons Anions • Are negatively charged • They are NON-METALS • gain electrons….. to obtain a stable electron configuration (like a noble gas) • They have an “ide” ending • E.g. Sulfide (S 2-) • • • • E.g. Fluorine ion Gains 1 electron It tries to have the same configuration as Neon F-1 has 10 electrons • Try: Oxygen Ion • Gains_____ electron(s) • It tries to have the same configuration as _____ • O2- has ________ electrons B. Polyatomic Ions • Are a group of atoms that act like anions. (Except: ammonium…it acts like a cation) • They are located at the top of the periodic table They don’t use bi anymore… use hydrogen instead Different Ways of Writing Acetate − CH3COO or C2H3O − EELR of Ions • It is a diagram that shows the following: – The Nucleus – Energy Levels – Valence electrons • The only difference is the electrons!!! Electrons = # of protons - the charge Nitride N3- # p+ = # e- = #n° = - atomic # - mass # _____ _____ ____ ____ - (-___) = ___ _____ - ___ = ____ ___ e___ ep+ = ___ n° = ___ ____ e- ______ Nitride N3- # p+ = # e- = #n° = - atomic # - mass # 7 14.01 7 7 - (-3) = 10 14.01 - 7 = 7.01 8 e2 ep+ = 7 n° = 7 7 10 e- Cadmium ion Cd 2+ # p+ = # e- = #n° = - atomic # - mass # ____ ____ ____ ____ - (+___) = ___ ____ - ____ = _____ ___ e___e___e___e___ ep+ = __ n° = __ ___ e- ___ Cadmium ion Cd 2+ # p+ = # e- = #n° = - atomic # - mass # 48 48 - (+2) = 46 112.41 - 48 = 64.41 10 e18 e8 e8 e2 ep+ = 48 n° = 64 46 e- 48 112.41 64 Iron (III) ion - atomic # - mass # Fe3+ # p+ = # e- = #n° = ___ ___ ____ ____ - (+___) = ___ ____ - ___ = _____ ==> __e__ e__ e___ ep+ = __ n° =___ ____ e- ____ Iron (III) ion - atomic # - mass # Fe3+ # p+ = # e- = #n° = 26 55.85 26 26 - (+3) = 23 55.85 - 26 = 29.85 ==> 30 5e8 e8 e2 ep+ = 26 n° =30 23 e- Draw an EELR for each of the following ions: 1. 2. 3. 4. 5. Sulfide strontium ion Copper (II) ion Iodide Vanadium (V) ion Elements • Metallic elements: – exist as single atoms (monatomic) – The formula is the symbol followed by the state E.g. [sodium] Na (s) • Non-metals: – Excluding noble gases don’t exist as single atoms… they are diatomic or polyatomic H2 N2 O2 F2 P4 S8 Cl2 Br2 polyatomic I2 Chemical Bonds • Are interactions that occur between atoms or molecules • There are two types: Covalent Ionic Covalent • Are formed when electrons are shared between atoms • It occurs between non-metals Each needs one electron to complete it’s 1st orbital 1+ 1+ Hydrogen Ions Single Bond 1+ 1+ Hydrogen Molecule H -- H H2 Ionic • Are formed when electrons TRANSFER from one atom to another • It occurs between a metal and a nonmetal. Compounds • are two or more substances that are held together by chemical bonds • There are two types: – Molecular – Ionic Molecular • Are solid, liquid or gas at room temperature • Contain only non- metals • Have a covalent bond • Don’t conduct electricity • may dissolve in water to produce either (a) neutral molecular solution (b) acidic solution Ionic Compounds • Are crystal solids at room temperature • occur because of a force of a attraction between the + and - ions • contain a metal and a non metal • have an ionic bond • Have high melting point and boiling points • Conduct electricity in water • May dissolve in water to produce either a (a)neutral ionic solution (b)basic solution. Ionic & Molecular Compounds Ionic Molecular cation + anion (metal + non-metal) all elements are non metals NO PREFIXES PREFIXES ALL SOLIDS AT R.T. SOLIDS, LIQUIDS & GAS Solutions conduct electricity solutions do not conduct electricity solutions are basic or neutral solutions are acidic or neutral ex. NaCl ex. OF2 Identify if it is M or I • A yellow gas forms a neutral solution_____ • A purple solid dissolves in water to produce a conducting solution _____ • A white solid dissolves in water and turns red litmus paper blue ______ (solutions) • A yellow gas forms a neutral solution____M_ • A purple solid dissolves in water to produce a conducting solution __I___ • A white solid dissolves in water and turns red litmus paper blue __I____ Naming & Writing Formulas For Molecular & Ionic Compounds Naming Molecular Compounds Non-metal + Non-metal • Step 1: write the element name for the first non-metal add a prefix ….(if there is more than one atom) • Step 2: Write the second element name and add an ide ending Add a prefix Exceptions • DO NOT use any prefixes at all if the first element is hydrogen ……these are acids Prefixes 6= hexa 7= hepta 3= mono di tri 8= octa 4= tetra 9= nona 5= penta 10 = deca 1= 2= Examples • P4O10 tetraphosphorus decaoxide • BrH7 bromine heptahydride • H 2S hydrogen sulfide Try the Following • CO(g) carbon monoxide • CO2(g) carbon dioxide • N3F8 Trinitrogen octafluoride Writing Formulas for Molecular Compounds • Steps: Write each elements symbol Write the subscript number (the prefix) • E.g. dinitrogen oxide disulfur oxide N2O S20 Try the Following • oxygen dibromide OBr2 • diphosphorus pentasulphide P2S5 • carbon tetraiodide CI4 • phosphorus pentachloride PCl5 Molecular Compounds that Must be memorized !!! NH3 ( g) = ammonia H2O ( l) = water H2S ( g) = hydrogen sulphide CH4 ( g) = methane CH3OH ( l) = methanol C2H6 ( g) = ethane C2H5OH ( l) = ethanol C6H12O6 ( s) = glucose C12H22O11 ( s) = sucrose O3 ( g) = ozone H2O2 ( l) = hydrogen peroxide Naming Binary Ionic Compounds Metal + non-metal • DO NOT USE PREFIXES • Steps 1.Write the metal 1st 2. Write the non-metal 2nd with an ide ending E.g. NaF sodium fluoride Na2S sodium sulphide two sodium ions are bonded with one sulphide ion… this doesn’t matter for naming ionic compound Try the Following • • • • • • • LiF KCl BeS Rb3P MgF2 Na2O CsBr lithium fluoride potassium chloride beryllium sulphide rubidium phosphide magnesium fluoride sodium oxide cesium bromide Try the Following • KCl potassium chloride • MgBr2 magnesium bromide • Ba3N2 barium nitride • ScP scandium phosphide Writing Formulas for Binary Ionic Compounds • Steps 1.Look up the symbol for each…& write the metal first 2.Balance the charges (total + charges = total – charges) 3.Use subscripts to show the # of each element sodium oxide 1+ 2 Charge Charge 1+ 2 = 2 + 2 1 = 2 Na2O calcium phosphide 2+ Charge 2+ 3= 3 Charge 32=6 6+ Ca3P2 Try the Following • magnesium chloride MgCl2 • calcium chloride CaCl2 • zinc sulphide ZnS • silver sulphide Ag2S • germanium oxide GeO2 • calcium arsenide Ca3As2 • magnesium nitride Mg3N2 Try the Following • lithium iodide LiI • zinc fluoride ZnF2 • strontium phosphide Sr3P2 • silver oxide • germanium arsenide Ag2O Ge3As4 Naming Multivalent Ionic Compounds transition metal + non-metal • Transition metal ions have more than one possible charge Cu2+, Cu+, Fe3+, Fe2+ • Steps 1. Write metal 1st with the charge in roman numerals Roman Numerals (I,II,III,IV,V,VI,VII) 2.Write non-metal second remember the charges have to balance Examples uranium (VI) fluoride U6+ F– UF6 chromium (III) nitride Cr3+ N3- CrN cobalt (II) chloride Co2+ ClCoCl2 Try the Following • AuBr gold (I) bromide • CrCl2 chromium (II) chloride • Co2O3 cobalt (III) oxide • VS2 vanadium (IV) sulphide • PuN2 plutonium (VI) nitride Naming Complex Ions Metal + complex ion • Steps: 1. Name the metal ion 2. Name the complex ion E.g.) PO43 Note: NH4+ (ammonium ion) is the only positive complex ion…it will take the place of a metal Examples • CaCO3 • Ba(OH)2 • (NH4)3N Solutions • CaCO3 Calcium carbonate • Ba(OH)2 Barium hydroxide • (NH4)3N Ammonium nitride Try the Following • KIO3 potassium iodate • NaCH3COO sodium acetate • MgSO3 magnesium sulphite • NH4NO3 ammonium nitrate • Ca3(PO4)2 calcium phosphate Writing Formulas For Complex Ions • Steps: 1. Look up the symbol for each ion 2. Balance the charges • Note: if you need more than 1 complex ion to balance the charges use brackets 2+ 1- • E.g. Ca(CH3COO)2 Try the Following • aluminum phosphate AlPO4 • calcium sulphite CaSO3 • scandium acetate Sc(CH3COO)3 • ammonium sulphate • nickel (II) phosphate • aluminum chlorate (NH4)2SO4 Ni3(PO4) Al(ClO3)3 2 Solubility Will the compound dissolve in water? Soluble • Refers to whether or not the compound dissolves in water • If it is…. the compound is aqueous (aq) • All acids are soluble • Some ionic compounds are soluble… the rest are solids Is It soluble? • This will apply to ionic compounds (only) • Steps 1. Find each ion in the boxes across the top 2. if it is soluble it will have (aq) aqueous 3. If it does not dissolve it will have (s) solid. Determine if the following compounds are soluble in water. Use the proper subscript to indicate the state. • • • • • • • • AgCl BaCO3 LiOH Ca2(PO4)3 NaCl CaI2 Pb(NO3)2 HMnO4 • AgCl (s) • BaCO3 (s) • LiOH (aq) • Ca2(PO4)3 (s) • NaCl (aq) • CaI2 (aq) • Pb(NO3)2 (aq) • HMnO4 (aq) Acids & Bases Acids • They are always soluble in water • Conduct electricity • Taste sour • React with metals to produce hydrogen gas (H2(g)) • Neutralize a base • they ALWAYS have hydrogen ….usually as the first element • E.g. HCl(aq) , H3PO4(aq) • There are three types: Binary Oxo Organic Binary Acids • contain only H and one other element (Cl, Br, etc.) • E.g. HCl (aq) Oxo Acids • Contain H and Oxygen • E.g. H3PO4(aq) Organic Acids • Contain C, H, & O • The H is written at the end • All have COO• E.g. CH3COOH(aq) – acetic acid C6H5COOH(aq) - benzoic acid HOOCCOOH(aq) – oxalic acid Acid Indicators • Turns blue litmus paper red • Able to turn bromothymol blue to yellow • Phenolphthalein remains colorless • E.g. lemon juice Bases • Are usually soluble in water • Conduct electricity (not weak ones) • Neutralize acids • Taste bitter • Usually solids • Feel slippery Base Indicators • Turns red litmus paper blue • Bromothymol blue remains blue • Turns phenolphthalein pink • E.g. baking soda, Rolaids, soap, Draino crystals Naming Acids • Steps: Hydrogen ____ide becomes hydro____ic acid Hydrogen ____ate becomes _______ic acid Hydrogen ____ ite becomes _______ ous acid Examples • HF (aq) hydrogen fluoride = hydrofluoric acid • H2SO3 (aq) hydrogen sulphite = sulphurous acid • H3BO3 (aq) hydrogen borate = boric acid • HCl (g) Hydrogen chloride (not an acid) Try the Following hydrosulphuric acid phosphorus acid carbonic acid hydrogen sulphide 1+ 2- H2S (aq) hydrogen phosphite 1+ 3- H3PO3 (aq) hydrogen carbonate H2CO3(aq) 1+ 2- Writing Acid Formulas • Steps: 1. Use the naming rules in the opposite direction • Example: hydrosulphuric acid hydrogen sulphide H2S(aq) Try the Following • carbonic acid hydrogen carbonate H CO 2 3(aq) • chlorous acid hydrogen chlorite HClO2(aq) Naming Bases • Steps: 1. Write the metal name 1st 2. Write hydroxide or bicarbonate E. g. NaOH sodium hydroxide Try the Following • KOH • Ba(OH)2 • NaHCO3 potassium hydroxide barium hydroxide sodium bicarbonate Chemical Reactions • Can cause a physical or a chemical change • Always results in the formation of a new substance • Evidence: 1. Temperature change 2. Formation of a precipitate 3. Colour change 4. Gas produces Reactants Products balancing 1 Zn(s) + 2 HCl(aq) states 1 ZnCl2(aq) + 1 H2 (g) states Energy Changes • Can occur in the form of heat, light, electrical, or mechanical • There are two types: Endothermic Exothermic • Endothermic Energy is absorbed (enters) Reactants + Energy products • Exothermic Energy is released (leaves) Reactants product + energy Balancing Equations • There must be equal numbers of each element on both sides of the equation Use lowest numbers Example ____Mg(s) + ___ O2(g) ___ MgO(s) ____ H2O(l) ____H2(g) + ____ O2(g) • When chemicals react they follow the Law of Conservation of Matter: Matter can not be created or destroyed it only changes form • Mass of reactants = mass of products Counting Practice • How many of each element are in the following compounds? 1. NaCl 5. NH4CH3COO 2. BaBr2 6. 3 (NH4)2S 3. (NH4)3P 7. 2 CaCl2 4. Ba(OH)2 8. 8 PbI2 9. 4 Zn(CH3COO)2 Balancing Practice ____ Cu(s) + ____ AgNO3(aq) ____ Ag(s) + ___ Cu(NO3)2(g) ___ Cl2(g) + ____ NaBr(aq) ____ Br2(l) + ____ NaCl(aq) ____ KI(aq) + ____ Pb(NO3)2(aq) ___ PbI2(s) + ___NO3(aq) ____ CH4(g) + ____ O2(g) ____ CO2(g) + ____ H2O(g) Types of Reactions • There are 5 types of reactions: Simple Composition Simple decomposition Single replacement Double replacement Hydrocarbon combustion Composition/ Formation Reactions • Elements combine to form a compound Element + element compound (s) • These are usually exothermic E.g. 2 Mg (s) + O2 (g) 2 MgO(s) Try the Following Mg(s) + Cl2(g) 2+ 14 Fe(s) + 3 O2(g) 3+ 22 Zn(s) + 2+ O2 (g) 2- MgCl2(s) 2 Fe2O3(s) 2 ZnO(s) Simple Decomposition • Compound decomposes into its elements Compound element + element • These are usually Endothermic E.g. 2 H2O(l) 2 H2(g) + O2(g) Try the Following 2 HMnO4(s) 2 HCl(g) Pb(NO3)2(s) H2(g) + 2 Mn(s) + 4O2(g) H2(g) + Cl2(g) Pb(s) + N2(g) + 3 O2(g) Single Replacement • An element reacts with an ionic compound to form a different element and compound element + compound element + compound • This occurs in water (use solubility chart) E.g. Cu(s) + 2 AgNO3(aq) 2 Ag(s) + Cu(NO3)2(aq) Example Cl2(g) + 2 NaBr(aq) Br2(l) + 2 NaCl(aq) Try the Following Zn (s) + 2 NaCl (aq) ZnCl2 (aq) + Na (s) 2 Pb (s) + Cu(NO3)2 (aq) Pb(NO3)2 (aq) + Cu (s) Mg (s) + 2 HOH (l) (g) + H (s) Mg(OH) 2 2 2 KCl (aq) + Br2 (l) 2 KBr (aq) + Cl2 (g) Double Replacement • Two ionic compounds react to form two different ionic compounds compound + compound compound + compound • It occurs in water (solubility chart) • There are two types of reactions: Precipitation Neutralization a. Precipitation Reaction • One product that is formed is insoluble compound + compound insoluble + compound compound E.g. Pb(NO3)2(aq) + 2 KI(aq) PbI2(s) + 2 KNO3(aq) solid b. Neutralization • An acid reacts with a base to form water and salt acid + base water + salt E.g. 1 HCl(aq) + 1 NaOH(aq) 1 H2O(l) + 1 NaCl(aq) Hydrocarbon Combustion • A hydrocarbon is made up of C &H (E.g. CH4) • Occurs when a hydrocarbon burns in the presence of oxygen • it always produces CO2 (g) + H2O (g) C?H? + O2(g) CO2(g) hydrocarbon E. g. CH4(g) + 2 O2(g) + H2O(g) CO2(g) + 2 H2O(g) Try the Following 6 CO2(g) + C6H12O6(s) + O 62(g) C2H6 (g) + O2(g) 2 CO2(g) + 3 H2O(g) 2 C2H6 (g) + O 7 2(g) 2 H 6 2O(g) C10H22 (l) + 31O2(g) 4 CO2(g) + 6 H2O(g) 20 CO2(g) + 22H2O(g) Other • any reaction that does not follow any of the above patterns E.g. Ca(OH)2(aq) + CO2(g) CaCO3(s) + H2O(g) HBrO3(aq) + 5 HBr HOH 3 (l) + Br2(l) 3 Mole • is a quantity equal to 6.02 x1023 atoms, ions, molecules, etc…. Which is Avogadro’s number • originally defined as the number of atoms in exactly 12 g of carbon-12 • it is used to determine the mass of all other elements Molar Mass • Is the mass of 1 mole of a substance Symbol – M Units – g/mol Steps: 1. Write the correct chemical formula. 2. List all elements present 3. Determine how many of each element are present 4. Multiply by the atomic molar mass of that element. 5. Find the sum. Example 1: Determine the molar mass of barium hydroxide Ba(OH)2 Ba 1 x 137.33 g/mol= 137.33 g/mol O 2 x 16.00 g/mol = 32.00 g/mol H 2 x 1.01 g/mol = 2.02 g/mol 171.35 g/mol Example 2: Determine the molar mass of magnesium nitrate Mg(NO3)2 Mg 1 2 N 6 O x 24.31 g/mol x 14.01 g/mol x 16.00 g/mol = 24.31 g/mol = 28.02 g/mol = 96.00 g/mol 148.33 g/mol Finding the # of Moles m = nM n = moles (mol) n =m M m = mass (g) M = molar mass (g/mol) E.g.1 How many moles are there in a 25.0 g sample of lithium sulfate? Li2SO4 = Li – 2 x 6.94 g/mol S - 1 x 32.06 g/mol O – 4 x 16.00 g/mol 109.94 g/mol n = m/M = 25.0 g 109.94 g/mol = 0.227 mol E.g.2 How many moles are there in a 32.8 g sample of potassium permanganate? KMnO4 = K – 1 x 39.10 g/mol Mn - 1 x 54.94 g/mol O – 4 x 16.00 g/mol 159.04 g/mol n = m/M = 32.8 g 159.04 g/mol = 0.20754… mol = 0.208 mol Example 3 What mass of copper (II) sulfate is present in a 0.3750 mol sample? CuSO4 m=? n = 0.3750 mol M= Cu – 1 x 63.55 g/mol S - 1 x 32.06 g/mol O - 4 x 16.00 g/mol 159.61 g/mol m = nM = (0.3750 mol)(159.61 g/mol) = 59.85 g Example 4 What mass of sodium hydrogen carbonate is present in a 2.50 mol sample? NaHCO3 m=? n = 2.50 mol M= Na - 1 x 22.99 g/mol H - 1 x 1.01 g/mol C - 1 x 12.01 g/mol O - 3 x 16.00 g/mol 84.01 g/mol m = nM = (2.50 mol)(84.01 g/mol) = 210g