SACE Stage 1 Yr 11 Chemistry End of Year Exam Notes

DefinitionsTechniques/Chemistry Building BlocksMixture: anything that can be separated into more than one simpler substance by physical change

Elements: can’t be broken down physically or chemically

Compounds: can be broken down into simpler substances by chemical means only

Heterogeneous: mixtures in different states

Homogeneous: mixtures in the same state

Immiscible: liquids that form layers – do not mix with each other

Miscible: liquids that are soluble in each other

Isotopes: elements with the same # of protons but different # of neutrons – the atomic # is the same but the mass # is different

Isomers: molecules with the same formula but different structural formula

Mass #: ‘A’ – sum of protons + neutrons

Atomic #: ‘Z’ - # of protons and electrons

Electronegativity: electron-attracting power of an element

Sublimation: transition of a substance from the solid phase to the gas phase without passing through the liquid phase. It separates solids from solids

Law of Conservation of Matter: matter cannot be destroyed nor created; only converted from one form to another

Law of Conservation of Mass: during a chemical reaction there is no change in mass

Bonding TheoryCations: positively charged ions

Anions: negatively charged ions

Polyatomic Ions: ions that include two or more elements

Non-polar: when the bonding pairs of electrons are shared equally between two atoms; two atoms of equal Electronegativity simultaneously attracting a pair of electrons

Polar: formed between elements with different electronegativities

Valence Electrons: electrons in the outer, unfilled shells. These are involved in bonding.

Acid-Base Theory/QuantitiesMole: the amount of substance containing 6.02 x 1023 particles

Amphoteric: substances that can act as an acid or base – 2H2O H3O+ + OH-

Ionisation: the formation of ions in solution

Strong Acid: an acid that completely ionises

Weak Acid: an acid that partially ionises

Strong Base: readily produces OH- (hydroxide ions)

Weak Base: does not readily produce OH- (hydroxide ions)

Alkali: a soluble metal hydroxide

Alkaline: basic

Indicators: a substance, which will tell by colour if a solution is acidic, alkaline or neutral

Dissociation: when salts dissolve in water

Concentrated Solution: have a large amount of solvent and a small amount of solute

Dilute solution: have a small amount of solvent and a large amount of solute

Neutralisation: the reaction between an acid and a base

Redox & ElectrochemistryOxidation: a gain in oxygen; loss of electrons; increase in oxidation number

SACE Stage 1 Yr 11 Chemistry End of Year Exam Notes Reduction: a loss in oxygen; gain of electrons; decrease in oxidation number

Oxidation Numbers: numbers assigned to different elements in redox equations to simplify the understanding of the process

Oxidising Agents: are themselves reduced

Reducing Agents: are themselves oxidised

Galvanic Cells: create an electric current from spontaneously occurring redox reactions

Electrolytic Cells: require electricity to drive redox reactions that do not happen simultaneously

Redox Reactions: electron transfer reactions

Organic ChemistryOctane Number: measure of the ignition quality of gas (gasoline or petrol)

Catalytic Cracking: the process of converting larger and less useful alkanes molecules into smaller, more useful ones. Catalytic cracking is done at a lower temperature than thermal cracking, in the presence of a catalyst

Isomerisation: the conversion of a compound into an isomer of itself

Catalytic Reforming: a chemical process that changes the shape of the hydrocarbon molecules using a catalyst to speed up the reaction

Substitution Reactions: the replacing of one atom by another atom

Addition Reactions: a reaction in which one molecule bonds covalently with another molecule without losing any other atoms

Hydrocarbons: chemical compounds that contain only carbon and hydrogen bonds

PolymersPolymer: a naturally occurring or synthetic compound consisting of large molecules made up of a linked series of repeated simple monomers

Monomer: a molecule that can be bonded to other identical molecules to form a polymer

Repeating Unit: the result of a monomer, which has been polymerized into a long chain/the simplest structural entity of a polymer chain

Ions: charged atom

Molecule: group of atoms joined together

Electrolyte: liquid that conducts electricity

Homologous Series: a group of organic compounds having a similar functional group

Functional Group: an atom or group of atoms that gives an organic molecule its specific property

Thermoplastics: melt easily when heated eg. Polystyrene

Thermosetting: char when heated eg. Bakelite

Hydrophobic: substances that do not dissolve in water eg. Oil and sulfur. They are generally non-polar and include hydrocarbons, metallic substances and elements.

Hydrophilic: substances that dissolve easily in water eg. Sodium chloride and glucose. They usually contain polar or ionic groups that are attracted to either of the polar ends of water molecules

Cross-links: covalent bonds that form between polymer chains – if the number of cross-links is small, an elastomer will result. If the number is large, a hard flexible thermosetting polymer will be produced.

Isotactic: a linear polymer with the side branches arranged on the same side. Due to greater effect of dispersion forces, such polymers can pack together closely, producing a substance, which has a high density and is rigid and tough with a high softening temperature

Actactic: when branches occur at irregular points on both sides of the chain. The chains of molecules cannot get as close together and a low density substance is formed

Fractional Distillation: a manufacturing process that separates the different components in a chemical mixture according to their different boiling points. The liquid is raised to boiling and vapours pass through a tubular column where temperature is gradually lowered along its length.

SACE Stage 1 Yr 11 Chemistry End of Year Exam Notes Components with a higher boiling point are collected. Gasoline, kerosene and naphtha are fractions separated from crude oil using fractional distillation.Diagram:

Wine Making:Wine can be produced by fermentation and distillation. Fermenting sugar with yeast, which contains enzymes, and limewater, then incubating the substance can breakdown the yeast into ethanol and carbon dioxide. Then through fractional distillation, heating the substance above 78o, ethanol can be extracted.

Note:1. Metal oxides tend to react with water to form basic solutions of the metal hydroxide

2. Non-metal oxides tend to form acidic oxides

3. Concentrated H2SO4 does not conduct electricity dilute H2SO4 does

4. The presence of H3O + ions is indicative of an acidic solution

5. The presence of OH - ions is indicative of an alkaline/basic solution

6. Water – Amphiprotic substance Proton Acceptor: H2O + H+ H3O+

Proton Donor: 2H2O H3O+ + OH-

7. Inert electrodes – carbon graphite or platinum

8. As molecular size increases, dispersion forces increase, therefore boiling point increases

9. Benzene is the basis for aromatic chemistry

10. All nitrates are soluble

11. Ethanoic acid – acetic acid

12. Metals lose electrons, non-metals gain electrons

13. CH3COOH + H2O = CH3COO - + H 3O +

14. Polar substances – element that has the higher electronegativity pulls the electrons in.

15. Zinc is used to galvanise steel

16. Sulfurous acid H2SO3

17. Diprotic (acts as a base and acid) – eg. H2SO4 H2SO4 + NH4 (NH4)2SO4 HNO3 + NH3

NH4NO3

Planar Linear V-shaped Trigonal Planar Tetrahedral

TECHNIQUES OF CHEMISTRYTypes of mixtures:SOLID-SOLID oresLIQUID-SOLID sand & waterLIQUID-LIQUID (miscible) ethanol and water; (immiscible) oil and water

Separation Techniques:

SACE Stage 1 Yr 11 Chemistry End of Year Exam Notes HETEROGENEOUS: Filtration (liquids from suspensions)

Separating funnel (2 immiscible liquids)Decantation (solid from liquid)

HOMOGENOUS: Crystallisation (dissolved solid in liquid)Sublimation (solids from solids)Evaporation (dissolved solid from a liquid)Fractional Distillation (liquids in liquids with different boiling points)Chromatography (separates pigments from dyes)

TRENDS IN THE PERIODIC TABLEMetallic Character:Across: decreases (attraction force of nucleus increases with increasing number of protons)Down: increases (electrons are less attracted to the nucleus, they are shielded by the increasing # of shells

Atomic Size: Across: decreases (the attraction force of the nucleus increases with the increasing # of

protons, and so pulls the electrons closer)Down: increases (increasing # of electron shells)

Reactivity:Highest in the middle, lowest at the ends/Most reactive – Fluorine

Electronegativity:Across: increases (fluorine is the most electronegative element. The further away an element

is placed from fluorine in the periodic table, the less electronegative it is)Down: decreases (increasing inner shells shield outer shell electrons from the nucleus)

CHEMICAL EQUATIONSCombination: A + B AB

Decomposition/Dissociation: AB A + B

Combustion: substance + O2 CO2 + H2O

Precipitation: AB + CD AC + BD (forms an insoluble substance)

Displacement: AB + C AC + B

Neutralisation: acid + base salt + water1. acid + metal salt + hydrogen2. acid + metal carbonate salt + H2O + CO2

3. acid + metal oxide salt + water4. acid + metal hydroxide salt + water

BONDING THEORYMELTING POINT

H L Covalent Molecular

CONDUCTIVITY OF SOILDS

H LMetallic Bonding

CONDUCTIVITY IN MOLTEN STATE

H L Ionic Bonding Covalent

Network

SACE Stage 1 Yr 11 Chemistry End of Year Exam Notes

METALLIC BONDING Metals & MetalsDefinition: positively charged cations in a sea of electrons

Properties of metals and non-metalsMetals: lustrous, conduct heat and electricity, malleable, high melting point and boiling point, solids @ room temperature except mercury

Non-metals: dull, non-conductors, brittle, low density and low melting and boiling points

IONIC BONDING Non-metals & MetalsDefinition: the bonding between metals and non-metalsIonic bonding involves one atom (metal) that is willing to give up its electrons for stability

Properties1. Ionic compounds are crystalline solids. Positive and negative ions attract one another and build

a giant structure – IONIC LATTICE

2. Ionic compounds are hard to melt. High MPt – attraction between +ve and –ve ions are strong

3. Most ionic compounds are soluble in water. Water gets in between ions to separate them

4. Ionic compounds conduct electricity when molten or when dissolved. +ve and –ve ions are able to carry current when they are free to move

COVALENT BONDING Non-metals & Non-metalsDefinition: the sharing of pairs of electrons between non-metals and non-metals

Properties1. Covalent compounds have low melting and boiling points. The chemical bonds between atoms

are strong, but the forces between molecules are weak. They take a little energy to overcome

2. They do not conduct electricity. All electrons are held in bonds. There are *no ions

3. They tend to dissolve in water – acids are exceptions

4. They tend to dissolve in covalent solvents. Solubility is dependent (mainly) on polarity. Covalent compounds are generally non-polar. As covalent compounds and solvents are both non-polar in general they will dissolve

5. They are very stable. The covalent bond is a strong bond.

Two types of covalent compounds:

Covalent molecular: atoms joined to make discreet units called moleculesProperties Non-conductors unless a reaction occurs with water to produce ions Low melting and boiling points Soft solids, liquids or gases

Covalent network: atoms joined to make a continuous network; no moleculesEg. Silicon dioxideOr carbon as graphiteOr carbon as diamond

Properties Non-conductors when solid or molten – electrons localised in covalent bonds or on the atoms Very high melting points – strong covalent bonding extending throughout the lattice Hard – atoms strongly bound in the lattice Brittle – distortion breaks covalent bonds

SECONDARY BONDING – THE BONDING BETWEEN MOLECULESThree types:1. Dispersion forces (the weakest type of intermolecular attraction)

Electrons in one atom can be attracted to the positively charged nucleus of anotherDepends on

SACE Stage 1 Yr 11 Chemistry End of Year Exam Notes a) number of electrons in the atom. More electrons, greater attractionb) shape of the molecule. Closer the molecules, stronger the attraction

2. Dipole-dipole interactionsAttraction between the positive end of a polar molecule with the negative end of another

3. Hydrogen bonding - FONNo electrons surrounding the hydrogen the nucleus is ‘unshielded’ allowing the negative end of another molecule to get much closer

ACID-BASE THEORYACIDS *proton donors Substances that always contain hydrogen, that is released in solution To act as an acid another substance must be presented to accept the proton

IONISATION HCl + H2O Cl - + H 3O +

Strong Acids

Weak Acids

H2SO4 Citric AcidHCl Acetic Acid

(vinegar)HNO3 Lactic AcidH3PO4 -(Mineral acids)

(Organic acids)

Properties1. Most common acids dissolve in water. Water is an able acceptor of protons and therefore

ionisations occurs2. Solutions of acids conduct electricity. Ions are formed3. Solutions of acids have many properties in common. All contain H3O+ ions (hydronium ions)

Structures of IMPORTANT acidsSulfuric acid H2SO4 Hydrochloric acid HCl Acetic Acid CH3COOH

BASES (Alkalis) *proton acceptorsBases neturalise acids to form salts

Properties1. Affect indicators2. Slippery feel3. React with oxides of non-metals – non-metal oxides are acidic4. Forms hydroxide ions (OH-)5. Eg. NH3 + H2O NH4

+ + OH-

pH CALCULATIONS 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

RED ACIDIC NEUTRAL BASICPURPLE

pH = -log <H3O+> - concentration pOH = -log <OH-> pH +pOH = 14

SALTS

SACE Stage 1 Yr 11 Chemistry End of Year Exam Notes Ionic compounds Soluble salts dissolve in water – DISSOCIATION

Preparation of Salts1. Direct combination: 2Na + Cl2 2NaCl2. Soluble salt preparation: (neutralisation reactions)3. Insoluble salt preparation: solution containing required ions are mixedeg. To prepare CuCO3 CuSO4 + Na2CO3 CuCO3 + 2Na+ + SO4

2-

THE MOLE CONCEPTRelative Atomic MassThe weight of 1 mole of particlesH = 1.01g Cu = 63.55g (PERIODIC TABLE)

Calculating ‘NUMBER OF MOLES’N (moles) = m (mass in g)/M (molar mass in g/mol)N = # of particles/6.02 x 1023

Empirical Formula – the simplest whole number ratio of atoms (or ions) in a compound (ionic and covalent network formulae are always empirical) Pg. 60

Molecular Formula – the actual number and kind of atoms in a molecule Pg. 61

Percentage composition Pg. 57

STOICHIOMETRY Reacting Mole Ratios – The Calculation1. A balanced equation2. Number of moles of the known3. Mole ratio – unknown/known4. Number of moles of the unknown

Example: Calculate the mass of CO2 formed when 6.0 g of carbon is burnt in excess oxygen.1. Equation: C + O2 = CO2

SACE Stage 1 Yr 11 Chemistry End of Year Exam Notes 2. Moles of known: mass of C = 6.0g, therefore # of moles (n) = 6/12 = 0.5mol3. Ratio: unknown/known = 1/14. Moles of unknown: m = n x M, 0.5 x 44 (12 + 16 + 16) = 22g

Concentration – mol/LM = MolarityC = n/v OR C = (m/M)/V(L)

REDOX – REDUCTION & OXIDATION occur concurrently

Common oxidising agents Common reducing agentsO2 O2- Alkali metal

MM+

ClO- Cl- CO CO2

H2O2 H2O SO32- SO4

2-

NO3- NO2 Fe2+ Fe3+

MnO4- Mn2+ H2S S

Cl2, Br2 Cl-, Br- H2O2 O2

H+ H2 I- I2CrO7

2- Cr3+

Balancing Redox Equation1. Balance the atoms involved2. Balance oxygen by adding H2O3. Balance Hydrogen by adding H+

4. Balance the charge by adding e-s

GALVANIC CELLS Chemical to ElectricalSalt Bridge: Ion balance

ELECTROLYTIC CELLElectrical to Chemical

Electrolytic cells are used for:1. Extracting Al2. Purify metals3. Electroplate4. Make chemicals

Factors affecting electrolysis1. Concentration of electrolyte

Dilute NaCl Anode: 2H2O 4H+ + O2 + 4e-

Cathode: 2H2O + 2e- H2 + 2OH-

Concentrated NaCl Anode: 2Cl- Cl2 + 2e-

Cathode: 2H2O + 2e- H2 + 2OH-

SACE Stage 1 Yr 11 Chemistry End of Year Exam Notes Moletn NaCl Anode: 2Cl- Cl2 + 2e-

Cathode: Na2+ + e- Na

2. Nature of electrolyteCuCl (inert electrodes – carbon graphite or platinum)Anode: 2Cl- Cl2 + 2e-

Cathode Cu2+ + 2e- Cu

3. Nature of electrodesActive electrodes (metal) – CuSO4 electrolyteAnode: (impure Cu) Cu Cu2+ + 2e-

Cathode: (pure Cu) Cu2+ + 2e- Cu

Electroplating

Difference & Similarities between Galvanic and Electrolytic CellsGalvanic Cells Electrolytic CellsChemical to electrical Electrical to chemicalAnode (negative), cathode (positive) Anode (positive), cathode

(negative)Voltmeter Battery cellMore reactive metal oxidises @ the anode

Half-cells not separated

ORGANIC CHEMISTRYPhotosynthesis 6CO2 + 6H2O C 6H1206 + 6O2

Respiration C6H12O6 + 6O2 6CO 2 + 6H2O + ENERGY

HOMOLOGOUS SERIESCharacteristics:1. each member has similar chemical properties2. physical properties change with increasing chain length

- melting point/boiling point increase as chain length increases- solubility decreases

ALKANES CnH2n+2 saturated (only C-H, C-C bonds) and therefore contains the most # of hydrogen’s per molecule General formula: Methane, ethane, propane, pentane, hexane, heptane, octane, nonane, decane

Physical Properties1. insoluble in water, soluble organic (non-polar) solvents2. low melting and boiling points3. unreactive4. do not react with – concentrated acids/alkali’s, strong oxidising agents, bromine (although they

will if heated or in bright light

Substitution reaction: CH4 + Br2 CH3Br + HBrCombustion: CH4 + 2O2 CO2 + 2H2O

ALKENES CnH2n unsaturated – contain one C=C double bond

Physical Properties insoluble in water, soluble in non-polar solvents low melting and boiling points

SACE Stage 1 Yr 11 Chemistry End of Year Exam Notes Chemical Properties Combustion: due to higher ratio of carbon to hydrogen, alkenes burn with a luminous, smoky

flame, indicative of incomplete combustion

Addition of Bromine: C2H4 + Br2 C2H4Br2 DECOLOURISESAddition of bromine water to an alkene will result in decolourisation of the bromine water/ No reaction will occur with alkanes

Addition of Hydrogen: C2H4 + H2 (Ni catalyst) C2H6

This is prevalent in the production of margarine: Vegetable oil + nH2 (Ni catalyst) Fat

Addition of Water:

Reaction with Acids:

Reaction with H2SO4:

ALKYNES CnH2n-2 Unsaturated; contains a triple bond

Physical Properties: same as alkenes

Chemical Properties Addition of Bromine: C2H3 + Br2 C2H2Br2 C2H2Br2 + Br2 C2H2Br4

Addition of HCl: Combustion: alkynes burn with a smoky, luminous flame. In pure oxygen combustion occurs

C2H2 + 5/2O2 2CO2 + H2O

ALCOHOLS CnH2n+1OHPreparation:1. Fermentation of sugar: C6H12O6 2C2H5OH + 2CO2

2. Ethene with water: C2H4 + H2O C2H5OH3. Reduction of alcohol with sodium: CH3OH + Na ½H2 + CH3ONa

Physical Properties: Methanol propenol are completely soluble in water Butanol , solubility in water decreases All soluble in organic solvents As chain length increases, so does boiling point

Chemical Properties: Combustion – clean burning: C2H5OH + 3O2 2CO2 + 3H2O *Oxidation:

o In air: C2H5OH + O2 CH3COOH (vinegar/acetic acid) + H2Oo With acidified Cr2O7

2-: C2H5OH (Cr2O72-/H+) CH3COOH orange to green

CARBOXYLIC ACIDSOrganic Acids weak “only partially ionise”R-COOH Carboxyl GroupThe first in series:Methanoic acid HCOOH Ethanoic acid CH3COOH Propanoic acid C2H5COOH Butanoic acid C3H7COOH

SACE Stage 1 Yr 11 Chemistry End of Year Exam Notes

Carboxylic acids are weak electrolytes They neutralise bases, react with carbonates and hydrogen carbonates Sharp taste, characteristic odour

o Eg. Citrus fruits – citric acid (ascorbic acid); rhubarb – oxalic acid; vinegar - ethanoic acid (acetic acid)

Ethanoic acid + sodium hydroxide: CH3COOH + NaOH CH3COONa + H2OMethanoic acid + sodium carbonate: 2HCOOH + Na2CO3 2HCOONa + CO2 + H2O

ESTERSEsters are prepared when an alcohol and a carboxylic acid are heated, under reflux, in the presences of a catalyst (conc. H2SO4)

Esters are named after the alcohol acidALCOHOL

ACID ESTER

Ethanol Methanoic acid

Ethyl methanoate

1-propanol

Ethanoic acid Propyl ethanoate

Esterification is a condensation reaction because H2O is also producedEsters have a fruity odourEsterification examples:Methanol and butanoic acid CH3OH + C3H7COOH (H2SO4 cat, reflux) CH3OOCC3H7 + H2O

Ethanol and methanoic acid

1-propanol and methanoic acid

Ethanol and propanoic acid CH3CH2OH + CH3CH2COOH (H2SO4 cat, reflux) CH3CH2OOCCH3CH2 + H2O

POLYMERS & CLEANING AGENTSPlastics: can be mouldedElastomers: stretchyAdhesives: cement by forming more bondsFibres: threadlike and can be woven

Cross-links: covalent bonds that form between polymer chains – if the number of cross-links is small, an elastomer will result. If the number is large, a hard flexible thermosetting polymer will be produced.

Natural fibres:

SACE Stage 1 Yr 11 Chemistry End of Year Exam Notes Proteins – hair, wool, silk ANIMAL Monomer: Amino acids composed of C, H, O, NCarbohydrates – linen, cotton, and hemp PLANT Monomer: glucose C6H12O6

Synthetic Fibres:Rayon – cellulose monomer but cellulose is rearranged by humansOther synthetics – nylon, polyesters, polyvinyl chloride

Polymerisation - the linking together of monomers to form a polymer chain1. Addition polymerisation: occurs when monomer molecules link without the loss of atoms. The monomer usually has at least one carbon-carbon double bond per molecule – monomers (usually alkanes) add to form long chains Eg. Polyethene

2. Condensation polymerisation: occurs when one or more compounds (such as water) are produced as the monomer molecules linkEg. Polyester – diol + diacid – polyester

Nylon – diamine + diacid - polyamide

Soaps/SaponificationFats/oils that contain triglyceride, their ester linkages, are hydrolysed in water to form glycerol and carboxylic acids. Sodium hydroxide is then added to neutralise the acids to form three soap molecules. Ionic hydrophilic head (-COO-Na+), hydrocarbon tail – hydrophobic, have the general formula RCOO-

Na+

Detergents The hydrocarbon tail must be joined to an ionic head in the manufacture of detergents The ionic heads are either a sulfate ion or a sulfonate ion obtained from sulfuric acid (catalyst)

How soaps and detergents work When soaps and detergents dissolve in water, surfactant ions are produced in solution The sodium ion has no function in the cleaning process Hydrocarbons are insoluble in water but soluble in oils or grease, whereas ionic compounds are

usually soluble in water but insoluble in oil or grease since surfactant molecules contain both a hydrophilic and hydrophobic part, they dissolve in both

Detergents The hydrocarbon tails mix with the particle of grease and surround it The ionic head stays in the water

SACE Stage 1 Yr 11 Chemistry End of Year Exam Notes The particle of grease comes off the surface and remains suspended in the water, forming a

grease micelle If excess detergent is added to the water, the detergent molecules will arrange themselves so

that their non-polar tails point toward each other, leaving their polar heads facing out toward the water

Heating the water and stirring it helps loosen grease and dirt particles from the surface being cleaned

Detergents form a lather with water which helps to hold suspended particles of grease and dirt

Bleaches HClO hypochlorous acid Oxidation bleach Whiten paper, peppercorns, clothing Kill germs Household bleach contains sodium hypochlorite (NaOCl) or calcium hypochlorite (Ca(OCl)2) that

acts as disinfectants, bleaches and deodorises Cotton, paper all bleached by HClO