Mass spec- molecular ion peak m/z to give Mr, fragment ions to identify parts of ion. Cl can be Mr 35 or 37. Br can be Mr 79 or 81.
Combined Techniques
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A Level
Summary of Qualitative Analysis of Organic
Must learn these. This is qualitative analysis. Testing Phenol: Phenols acidic so can be tested using pH indicator paper. However phenols not as acidic as carboxylic acid and do not react with sodium carbonate. Or can add bromine at room temperature...
Chromatography and Spectroscopy
Chromatography: Chromatography is used to separate individual components from a mixture of substances. Used in analysis of drugs and other mixtures.
TLC Chromatography
TLC: Thin Layer Chromatography is quick and inexpensive. Indicates how many components there are in mixture. Phase: Stationary phase is solid adsorbent, usually silica. Stationary phase lies on TLC place, usually glass or plastic. Mobile phase is liquid solvent. ...
Gas Chromatography
Gas Chromatography: GC MS enables products to be identified- by separating the components in a mixture and identify them by comparing with a database. GC MS used in forensics, environmental analysis and airport security. Number of products = number of peaks....
NMR (Nuclear Magnetic Resonance) Spectroscopy
NMR: Nuclear magnetic resonance spectroscopy to analyse organic compounds. Nuclei of atoms absorbs magnetic field and radio frequency radiation, absorption measured by NMR. Frequency required for resonance proportional to magnetic field strength. NMR used in...
Carbon- 13 NMR Spectroscopy
C-13 NMR: Carbon- 13 NMR spectrum tells us… number of different carbon environments from number of peaks AND types of carbon environments from chemical shift values. Remember carbon as no splitting. Chemical Environment: Carbon atoms bonded to different atoms...
Proton NMR Spectroscopy
Proton NMR: Proton NMR spectrum tells us… 1) Number of different proton environments from number of peaks. 2) Types of proton environment from chemical shift values. 3) Relative number of proton in each environment given from integration traces/ ratio numbers of...
Cis- Trans Isomerism in Complex Ions
Stereoisomerism: Complex ions display two types of stereoisomerism: cis- trans isomerism AND optical isomerism. Cis- Trans Isomerism: Some square planar and octahedral show show cis- trans isomerism. In complex ion, no double bond needed to restrict rotation....
Amino Acids
Amino Acids: An amino acid is an organic compound containing both basic amine, NH2, and acidic carboxylic acid COOH. α- Amino Acids: Body has 20 amino acids, all of which are α- amino acids where amine group attached to α carbon atom- the second carbon atom next to...
Optical Isomerism
Optical Isomerism only occurs in octahedral complexes containing two or more bidentate ligands. Optical isomers aka enantiomers are pair of non- superimposable mirror images of each other. Cis- isomers may also show optical isomerism such as above. In questions,...
Reactions with Amino Acid
1) Reaction of Amine Group: Amine group in amino acids is basic and reacts with acids to form salts, in same way as amine does. Reaction of Carboxylic Acids Group in Amino Acid… 2) Reaction of Carboxylic Acid Group with Aqueous Alkali: Amino acid reacts with...
Ligand Substitution and Precipitation
Ligand Substitution: A ligand substitution is a reaction in which one ligand in a complex ion is replaced by another ligand. Reactions of Aqueous Copper (II) Ions: When copper (II) sulphate is dissolved in water, pale blue complex ion formed [Cu(H2O)6] 2+ Ligand...
Amides and Chirality
Amides: Amides are products of reactions of acyl chlorides with ammonia/ amines. Stereoisomerism: Remember stereoisomerism are compounds with same structural formula but different arrangement of atoms in space. Types of stereoisomerism are optical isomerism and E/ Z...
Benzene
Benzene: Benzene is C6H6. Classed as an aromatic hydrocarbon or an arene. Two ways to draw benzene. Questions may use either, even though right one is misleading. Joined double benzene ring has 10 carbons and not 12. Physical Properties: Benzene is colourless,...
Condensation Polymers
Addition Polymerisation: AS alkenes form polymers by addition polymerisation. Monomer of addition polymerisation will contain C=C-. Double bond breaks (pi bond breaks) in polymer and is replaced by single bond. In monomer double bond should be at either side. Imagine...
Electrophilic Substitution Reactions of Benzene
Electrophilic Substitution: Benzene and its derivatives react with an electrophile which replaces a hydrogen atom on benzene. 1) Nitration of Benzene: Benzene reacts with nitric acid to form nitrobenzene in electrophilic substitution. Reaction catalysed by conc....
Polyester
Polyester and polyamides used as fibres in clothing. Polyesters: To form polyester, monomers joined together by ester linkages in a long chain. Polyesters can be made from one monomer OR two monomers… When a polymer made from one monomer. The OH and COOH must be...
Phenol
Phenols: Phenols contain a hydroxyl, -OH, directly bonded to an aromatic ring. Simplest member called phenol C6H5OH, same name as the group. Another example is 2- hydroxybenzoic acid below. Aromatic Alcohol: Remember an alcohol is –OH bonded to carbon chain. An...
Polyamides
Polyamides: Polyamides are condensation polymers when monomers joined together by amide linkages in long chain. Can be made from one monomer or two monomers… 3) Polyamides Made from One Monomer: - Polyamides made from one monomer containing either carboxylic acid...
Directing Groups
Activation: A group present in reactant that activates the ring, so aromatic ring reacts more readily with electrophiles. Deactivation: A group present in reactant that deactivates the ring, so aromatic ring reacts less readily with electrophiles. Activation and...
Hydrolysing Condensation Polymers
Hydrolysing: Condensation polymers can be hydrolysed using hot aqueous alkali e.g. sodium hydroxide OR hot dilute aqueous acid e.g. HCl. Wherever there is an amide or ester bond, can break it apart and forms products either side of it. Add water on. 5) Hydrolysing...
Carbonyl Compounds
Aldehyde: C= O or carbonyl group at the end. Written as CHO. Suffix –al. Ketones: C= O or carbonyl group in middle. Written as CO. Suffix –one. Carbonyl group needs to be numbered, unlike aldehyde- which always in position 1. Octanal- suffix starts with vowel, so...
Carbon- Carbon Bond Formation
Formation of Nitriles: Nitrile group is –CN. 1) Haloalkanes to Nitriles: Haloalkanes reacted with sodium or potassium cyanide NaCN/ KCN in ethanol. In this reaction length of carbon chain increased. This is an example of nucleophilic substitution. 2) Aldehydes/...
Identifying Aldehydes and Ketones
2, 4- DNP: A solution of 2,4- dinitrophenylhydrazine is used to detect presence of carbonyl functional group in aldehydes and ketones. If present, a yellow/ orange precipitate called 2,4- dinitrophenylhydrazone produced. Brady’s Reagent: In practical’s, 2,4- DNP...
Further Practical Techniques
Filtration under Reduced Pressure: Need Buchner flask, Buchner funnel, pressure tubing, filter paper and vacuum pump. This separates solid product from liquid. Process: Connect tube from vacuum pump to Buchner flask. Fit Buchner funnel to flask using Buchner rubber...
Carboxylic Acids
Carboxyl Group: Carboxyl group in carboxylic acid. Uses: Carboxylic acids found in medicines and vinegar. Naming: Methanoic acid HCOOH is simplest. As suffix starts with vowel, shorten butane to butan. Solubility of Carboxylic Acids: - Polar C=O bond and O-H...
Further Synthetic Routes
Important to identify all functional groups correctly on starting and target molecule. If two functional groups on compound, need to write reactions that change one functional group and then write reactions that change the other functional group, independent of one...
Carboxylic Acids Derivatives
Carboxylic Acid Derivatives: A derivative of carboxylic acid is a compound that can be hydrolysed to form the parent carboxylic acid. Esters, acyl chlorides, acid anhydrides and amides are derivatives of carboxylic acid. All carboxylic acid derivatives contain acyl...
Esters
An ester is a carboxylic acid derivative. Naming Ester: Put alcohol part first and then acid. Ester commonly used for perfumes or flavourings as they have a fruity smell. 1) Esterification: Esterification is reaction of an alcohol with carboxylic acid to form a...
Acyl Chloride
Acyl chloride is a carboxylic acid derivative. Don’t forget the HCl when reacting with acyl chlorides. 1) Preparing Acyl Chloride: Carboxylic acid and SOCl2 thionyl chloride. Produces gases SO2 and HCl. Carry out in fume cupboard as products harmful. Reactions...
Amines
Amine: Amines are organic compounds, derived from ammonia NH3 where hydrogen atoms in ammonia have been replaced by a group. Classifying Amines: Can get primary amine where one carbon atom attached to nitrogen (instead of hydrogen so leaves NH2). Secondary NH and...
Complex Ion Formation
Complex Ions: Transition metal ion form complex ions. Complex ions formed when ligands bond to central metal ion by coordinate bond. Ligands: Ligands are molecules or ions that donate lone pair of electrons to a central metal ion to form coordinate bond or dative...
Reactions of Amines
1) Bases: Amines act as bases (so react with acids to from salts) due to lone pair of electrons on nitrogen accepting a proton. This forms a dative covalent bond between lone pair of electrons on N and the proton- forming an ammonium ion. 2) Salt Formation: Since...
Complex Ion Shapes
Shape depends on coordination number. Six Coordinate Complexes: If complex ion has coordination number of 6, gives octahedral shape so 90 bond angles around central metal ion. When MnSO4 is dissolved in water. Forms complex ion with octahedral shape. Learn these...
Preparation of Amines
3) Formation of Primary Amines: Aliphatic. 1) Salt Formation: Ammonia has lone pair of electrons on nitrogen so ammonia acts as nucleophile. Substitution reaction of haloalkane and ammonia, forming ammonium salt. 2) Amine Formation: Ammonium salt reacted with aqueous...
Buffer Solutions
Buffer Solution: A buffer solution is a system that minimises pH changes when small amounts of acid or base added. Buffer solutions contains 2 things… Buffer solution contains weak acid, HA, to remove added alkali. Buffer solutions contain conjugate base, A- ,...
Buffer Solutions in the Body
Blood Plasma: Blood plasma needs to be at pH 7.4 due to enzymes. pH controlled by buffers such as the carbonic acid- hydrogencarbonate buffer. The body produces more acidic materials than alkaline. Buffers make sure H2CO3 not built up. Problems with pH: If pH falls...
Neutralisation
pH Meter: A pH meter consists of an electrode. pH reading displayed. pH meter more accurate than indicator paper, as pH meter does to 2 dp compared to whole number. If data logger attached to pH meter, can plot pH titration curve automatically. Experiment Monitoring...
Lattice Enthalpy
Giant Ionic Compounds: Giant ionic compounds have strong ionic bonds- electrostatic attractions between oppositely- charged ions. Must overcome to melt. Lattice Enthalpy: Lattice enthalpy is the enthalpy change that accompanies formation of one mole of an ionic...
Factors Affecting Lattice Enthalpy
Factors Affecting Lattice Enthalpy: Add up ionic radius/ charge if given a range of elements and compounds. When ions in two different groups, need to talk about both ionic charge and ionic size e.g. Mg2+ and Na+. Don’t write Na, write Na+. Don’t forget the...
Factors Affecting Hydration Enthalpies
Factors Affecting Hydration Enthalpies: Hydration enthalpies affected by ionic size and ionic charge in same way as lattice enthalpy. Effect of Ionic Size: Ionic size increase down a group. - MN+ is has a smaller ionic radius than Y+. - Attraction between ion and...
Redox Reactions
OILRIG: Oxidation is loss of electrons and increase in oxidation number. Reduction is gain of electrons and decrease in oxidation number. Redox: A reaction where both oxidation and reduction take place. Oxidation Number: A measure of the number of electrons that...
Entropy
Entropy: The greater the entropy, the greater the disorder. Units of entropy are JK-1mol-1 . 0K = no energy so minimum disorder. States of Matter: Generally changing from solids -> liquids -> gas by melting and boiling, increases entropy increase in disorder,...
Kc
Kc: Remember Kc = products/ reactants. Remember the larger the value, further away from position equilibrium and towards products- AS. Know how to work out Kc if given equilibrium concentrations. Now looking at how Kc calculated from experimental results. Kc...
Free Energy
Feasibility: Reaction can only occur if products have lower overall energy than reactants, then feasible or spontaneous. Gibbs’ Equation: The overall change during chemical reaction called free energy change- ∆G. Enthalpy change refers to heat transfer between...
Kp
Kp: Use Kp with gases. Same as Kc but equilibrium constant in terms of partial pressure instead of concentration. Products/ reactants. Balancing numbers is the power. If asked to write Kp expression, no square brackets and remember p… Only include gases, omit other...
Manganate (VII) Redox Titrations
Redox titrations similar to acid- base titration. If don’t know which way round colour changes, look at table to see what’s added. Manganate (VII) Titrations: Potassium manganate (VII) KMnO4 under acidic conditions. Potassium manganate can be replaced by other...
Controlling Position of Equilibrium
Already know le Chatelier’s principle… Concentration: If concentration increase, position of equilibrium shifts in direction that reduces concentration right/ left, so towards product/ reactants. Pressure: If pressure increased, position of equilibrium shifts...
Iodine/ Thiosulfate Redox Titrations
Iodine/ Thiosulfate Titrations: Oxidising agent must first oxidise I- ions to I2. Then thiosulfate ions S2O3 2- are oxidised and iodine reduced. Amount of iodine can be determined. As well iodine, other oxidising agents can be determined such as chlorate ions ClO- in...
Bronsted- Lowry Acids and Bases
Acid: An acid dissociates and releases H+ ions in aqueous solution. A Bronsted- Lowry acid is a proton donor. A strong acid completely dissociates AND a weak acid partially dissociates. Can measure current through an acid to determine if strong and weak acid....
Electrode Potentials
Voltaic Cell: A voltaic cell is a type of electrochemical cell, which converts chemical energy to electrical energy. Chemical energy from movement of electrons, so use redox reactions as they transfer electrons. Half Cell: A half-cell contains species present in...
pH Scale and Strong Acids
pH Scale: Uses negative logarithm of powers of 10. More manageable scale. H Ion Concentration: Low value of [H+ (aq)] = high value of pH. A change in one pH number is 10x the [H+ (aq)]. Measuring pH: The electrode in pH meter measures electrical potential of H+...
Predictions from Electrode Potentials
Predicting Feasibility: Can predict feasibility of reaction from standard electrode potentials. A reaction takes place when the one being reduced (and on left) has a more positive E o value than one being oxidised (and on right). This works as higher E o value means...
Acid Dissociation Constant Ka
Acid Dissociation Constant Ka: Tells us extent of dissociation. No Ka value for strong acid as completely dissociate. Units are moldm-3. Ka = [ H +(aq)][ A−(aq)] [ HA(aq)] Use this one if Q asks for Ka expression. Equilibrium Constant: Ka changes with temperature so...
Storage and Fuel Cells
Modern Cells and Batteries: Modern cells and batteries based on two electrodes with different electrode potentials. Three main times of cells- primary, secondary and fuel cells. Primary Cells: Primary cells are non- rechargeable. Electricity is produced by oxidation...
pH of Weak Acids
Ka can be calculated from equilibrium amounts. Approximations: Equation above can be simplified to equation below by assuming two things… Dissociation of Water: There is a small concentration of H+ from dissociation of water which is neglected. Therefore when HA...
D Block Elements
D Block Elements: Looking at scandium to zinc of period 4 of d block. All d block are metallic, so high MP, shiny, conduct electricity and heat. The highest energy sub-shell is a d sub-shell. Electron Configuration: Electrons added to 3d orbitals from 1 to 10....
pH of Bases
Determine if acid or alkali. Check if weak or strong before doing method. Also always check if 2OH or 2H as would be dibasic and would need to multiply conc x 2. Check in questions if given pKa or Ka. Kw: Ionic product of water- the ions in water H+ and OH-...
More Acid and Base Calculations
Addition of 25 cm3 of water to 100 cm3 of 0.100 mol dm-3 Ba(OH)2. Find pH. Dilution question. Given concentration of OH- in original volume but want to find out concentration of OH- in diluted volume. - Concentration x old volume/ new volume = concentration of OH-....
Combining Questions
Empirical and Molecular Formula: • Do elemental analysis by using percentage composition data to determine empirical formula and then molecular formula. • Sometimes volumetric analysis given, use Mr Moles to work out Mr. • If empirical formula and molecular formula...
Orders, Rate Equations and Rate Constants
Rate = change in concentration/ change in time. [A] is shorthand for ‘concentration of A’. Rate of Reaction: The change in concentration of a reactant or product per unit time. Units: Usually it is mol dm-3 s-1. -1 in superscript means ‘per’ or ‘divide’. Orders...
Chemical Reactions of Alkanes
Unreactive: C-C bonds non- polar. C- H non- polar as electronegativity of C and H similar. • Complete Combustion: Alkanes burn completely with plentiful supply of oxygen to produce carbon dioxide and water to give out heat. C gives CO2 and half of H gives H2O. •...
Concentration- Time Graphs
Colorimeter: Monitoring colour change/ concentration. Amount of light absorbed by solution. Experiment Method: Prepare standard solutions of known concentrations of solution. Choose filter with complementary colour to coloured chemical. Zero colorimeter with water....
Properties of Alkenes
• Three Sigma Bonds: For each carbon atom in double bond, three of the four electrons are used in three σ- bond/ sigma bond. • One Pi Bond: One electron left in p- orbital. Sideways overlap of two p orbitals on each carbon atom forms π-bond above and below plane of...
Rate- Concentration Graphs
Rate- Concentration Graphs: Zero Order: Straight horizontal line with zero gradient. Rate = k[A]0 so rate = k = Y intercept. Reaction rate does not change with concentration. Can confirm first order of reaction of graph by calculating two half-lives and constant....
Stereoisomerism
Stereoisomers: Compounds with same structural formula but different arrangement of atoms in space. So chemically different. • If asks what type of stereoisomerism- E/Z. • Why E/Z Isomerism: Stereoisomerism arises because… - Must have double bond as rotation around...
Rate- Determining Step
Reaction Mechanism: Reactions take place in series of steps called reaction mechanism. - Collision unlikely between more than 2 species in one step. - Also stoichiometry in rate equation may not match overall equation. Rate- Determining Step: The steps in reactions...
Reactions of Alkenes
Reactivity: Alkenes more reactive than alkanes as the π- electrons are more exposed than σ- bond electrons. The π- bond is weaker than σ- bond. • Addition Reactions: Each of these reactions involves addition of molecule across double bond, causing π- bond (double...
Rate Constants and Temperature
Temperature Increase: As temperature increases, rate increases and the value of rate constant k increases. This is due to two factors… Kinetic Energy: As temperature increases, particles move faster and collide more frequently. Activation Energy: Increasing...
Electrophilic Addition in Alkenes
• Electrophilic Addition: A reaction mechanism. • Electrophile: It is a species that is attracted to an electron- rich centre, where it accepts a pair of electrons to form a covalent bond. Usually a positive ion or contains δ+ charge. It can be something like HBr-...
Polymerisation in Alkenes
• Addition Polymerisation: Polymers are named as poly- (alkene monomer). • All alkene reactions in this topic are addition reaction so 100% atom economy- no waste products. • Remember n, should be on correct side and correct posiiton. • Repeat Unit: Repeat unit is...
Properties of Alcohols
Alcohols: Contain hydroxyl group. Simplest alcohol is methanol- CH3OH and it’s used as fuel, chemical feedstocks and solvents. Next in alcohol homologous series is ethanol and used in alcoholic drinks, fuel and solvent. • If make methanol using carbon monoxide it’s...
Chemical Reactions of Alcohols
Combustion of Alcohols: Alcohols burn completely in plentiful supply of oxygen to produce carbon dioxide and water, like alkanes. • Oxidising Agent: It is a solution of potassium dichromate, acidified with dilute sulfuric acid. Acidified potassium dichromate + reflux....
Chemistry of Haloalkanes
Naming Haloalkanes: If two+ halogen present, listed in alphabetical order. Like alcohols, haloalkanes classed as primary, secondary and tertiary. • Nucleophiles: An atom or group of atoms that is attracted to an electron- deficient carbon atom, where it donates a pair...
Organohalogen Compounds in the Environment
Organohalogen: Contain at least one halogen atom joined to carbon chain. Used in pesticides, polymers and refrigerators. • Ozone Layer: Ozone layer in the outer edge of the stratosphere. Only a fraction of gases making up ozone layer is ozone. Ozone absorbs the...
Practical Techniques in Organic Chemistry – Need to be able to draw all this.
Preparing a Sample of Organic Liquid: Will need Quickfit apparatus- 1) pearshaped/ round bottom flask, 2) receiver, 3) screw- tap adapter, 4) condenser and 5) still head. • Reflux: The continual boiling and condensing of a reaction mixture back to the original...
Synthetic Routes
Heat/ reflux is a condition for most of the reactions, so mention both, as well any acid catalysts. • AS Mechanisms- radical substitution, nucleophilic substitution and electrophilic addition.
Mass Spectrometry
Mass Spectrometer: Sample is placed, vaporised and ionised to form positive ions. Ions are accelerated. Heavier ions move slowly and more difficult to deflect than lighter ions, so ions of each isotope separated. In vacuum so no interference with other molecules. •...
Infrared Spectroscopy
Covalent Bonds: Covalent bonds can absorb infrared radiation, which makes the bonds vibratebonds bend or stretch more. Stretch and bend are two types of vibration. Bonds have energy normally and vibrate. • Wavenumber: Wavenumber is proportional to frequency and used...
Periodic Trends in Bonding and Structure
Semi- Metals: Elements near the diagonal divide are semi- metals or metalloids with in- between properties. • Metallic Bonding: The electrostatic attraction between positive metal ions and delocalised electrons. • Giant Metallic Lattice: Each atom has donated its...
Reaction Mechanisms
Covalent Bonds: Their bonds can be broken by homolytic fission or hetrolytic fission. • Homolytic Fission: Breaking of bond. Each of the bonded atoms takes one of the shared pair of electrons from the bond. Now both atoms are radicals- species with a single unpaired...
Qualitative Analysis
Quantitative Analysis: Example is titration. • Qualitative Analysis: Relies on observations. • Test for Anions: Carbonate, sulphate and halide. • Carbonate and Acids: Carbonates react with acids to form carbon dioxide. Na2CO3 (aq) + 2HNO3 (aq) -> 2NaNO3 (aq) + CO2...
Properties of Alkanes
Alkane Use: Components of natural gas and crude oil. • Sigma Bond: The type of covalent bonds in alkanes are called sigma bond- It is overlapping of two orbitals, one from each bonding atom. Positioned on line directly between bonding atoms. Each carbon atom in alkane...
Enthalpy Change
Enthalpy: H. The heat content that is stored in a chemical system. • Enthalpy Change: ∆ = − . • Conservation of Energy: Energy cannot be created or destroyed. Heat transferred between system and surroundings. • (Chemical) System: The chemical compounds being studied-...
Measuring Enthalpy Changes
Thermometer: It is part of surroundings so can measure temp change in surroundings. • Kelvin Scale: Scale starts at absolute zero 0 K or -273oC. 1 K rise = 1 oC rise. oC + 273 = K. • Calculating Energy Change: Energy change of surroundings is calculated using q =...
Bond Enthalpies
Average Bond Enthalpy: Enthalpy change when one mole of atoms of gaseous covalent bonds is broken. Use average bond enthalpies to calculate enthalpy changes of reaction ∆rH without experiments. To use must have energy required to break bond = endothermic = positive...
Hess’ Law and Enthalpy Cycles
Experiments: The experiments in previous section allow enthalpy changes to be determined directly. Hess’ Law determines it indirectly. • Difficult to determine standard enthalpy change of combustion directly as… - Carbon dioxide and water would also be formed. -...
Reaction Rates
Rate of Reaction: Change in concentration of a reactant used up or product formed in a given time. • Calculating Rate of Reaction: Rate (mol dm-3 s -1 ) = change in concentration (mol dm-3 ) / time (s). Time on x axis. • Working out rate of anything is change in...
Catalysts
Catalyst: A catalyst provides an alternative reaction pathway for reaction with lower activation energy. Catalyst regenerated/ not used up. Increases rate of reaction. Enthalpy Profile Diagrams: Reactants and product should be shown at correct levels with respect to...
The Boltzmann Distribution
Elastic Collisions: Molecules in gas move at high speed and collide with each other. Collisions are elastic as molecules do not slow down as a result of collision so no energy lost. • Energy of Molecules: In gas, liquid, or solution, some molecules move slowly with...
Dynamic Equilibrium and le Chatelier’s Principle
Reversible Reactions: A reaction that takes place in both forward and reverse directions if reversible. Equilibrium only in reversible reactions. • Dynamic Equilibrium System: Equilibrium that exists in a closed system when rate of forward reaction is equal to rate of...
Group 2
Group 2: Aka alkaline earth metals. • Redox Reactions: They are the most common type of reaction of Group 2 elements. Each metal atom is oxidised, losing two electrons to form a X2+ ion- the same electron configuration as noble gas. Another species will gain these two...
The Equilibrium Constant Kc
Equilibrium Constant: Kc. A measure of the position of equilibrium. • Equilibrium Law: Square brackets shorthand for ‘concentration of’. a, b, c and d are balancing numbers- the powers. A, B, C and D are the equilibrium concentrations of products and reactants. •...
The Halogens
Halogens: Group 17. Reactive. All halogens exist as diatomic molecules. • Characteristics: Fluorine is yellow gas. Chlorine is green gas. Bromine is red/ brown liquid. Iodine is grey solid. • Boiling Point Increases Down: - As you go down the group, greater number of...
Exam Technique- organic
If given unknown compound, identify what functional groups and the reactions and properties related to that. Use any hints in question about compound. First draw displayed formula if just given structural formula. • Pay most attention to the ‘weird’ stuff question...
Shapes of Molecules and Ions
Electron- Pair Repulsion Theory: Electron pairs arranged as far apart as possible to minimise repulsion. Number of bond pairs and lone pairs of electrons surrounding central atom determine shape. This holds the bonded atoms in a definite shape. - Name shape. - State...
Organic Chemistry
Organic is when it contains the element carbon. • Hydrocarbon: A compound containing hydrogen and carbon only. • Saturated: Contains single C—C bonds only. Unsaturated: Contains multiple carbon to carbon bond such as C=C bond. • Homologous Series: It is a series of...
Electronegativity and Polarity
Electronegativity: The ability of an atom to attract electrons in a covalent bond. • Periodic Table: - Across the periodic table, the nuclear charge increases and the atomic radius decreases. - Electronegativity increase up the periodic table and across the periodic...
Nomenclature of Organic Compounds
IUPAC- international organisation to standardise names. • 3 Types of Hydrocarbons: Aliphatic- containing carbon atoms joined in straight chain, branched chains or non- aromatic rings. Alicyclic- an aliphatic compound containing carbon atoms joining together in a non-...