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3.1.4 Energetics, A Level Chemistry, AQA Questions and Answers What values of deltaH do exothermic reactions have? Negative (less than 0) What values of deltaH do endothermic reactions have? Positive (more than 0) What do exothermic reactions do with energy? Give out energy What do endothermic reactions do with energy? Absorb energy Are oxidation reactions endo or exothermic? Exothermic Is combustion endo or exothermic? Exothermic Are thermal deco...

A-level AQA chemistry mechanisms Questions and Answers constant product for every nucleophilic addition-elimination of an acyl chloride HCl nucleophilic addition mechanism for carbonyls in nucelophilic addition mechanisms with carbonyls and cyanide ions, where do the cyanide ions come from KCN or NaCN (but not HCN bc it's highly toxic) in nucelophilic addition mechanisms with carbonyls and :H-, where does the :H- come from reducing agent what is the reducing ag...

AQA A Level Chemistry Aldehydes and Ketones Questions and Answers What is a carbonyl group? C=O What type of bond is C=O? Polar What are the effects of the carbonyl group being planar? There is no steric hindrance, so the bond can be attacked from any angle Why do nucleophiles attack carbonyl groups? The carbon is slightly positive How do you turn a primary alcohol into an aldehyde? Oxidise it How to you turn a carboxylic acid into an aldehyde? Reduce it...

AQA A-Level Chemistry (new spec) 1.3 Bonding Questions and Answers Ionic Bonding The electrostatic force of attraction between two oppositely charged ions formed by electron transfer Covalent Bonding A shared pair of electrons Dative Covalent Bonding (AKA Co-ordinate bonding) Formed when the shared pair of electrons in the covalent bond come from only one of the bonding atoms. Metallic Bonding The electrostatic force of attraction between the positive metal cations an...

AQA A-LEVEL CHEMISTRY PERIOD 3 Questions and Answers reaction of sodium with water- observation Floats, fizzes and moves on the surface of the water, molten. melts into a ball and disappears pH of sodium with water alkali, 12-14 sodium oxide formula Na2O What is the structure bonding in NaO ionic lattice, ionic bonding between Na+ ions an O2- ions Why is the melting point of sodium oxide high? ionic lattice with strong electrostatic forces of attraction between ...

AQA A Level Chemistry 3.1.12 - Acids and Bases Questions and Answers Bronsted-Lowry acid Proton donor Bronsted-Lowry base Proton acceptor pH Measure of acidity by measuring concentration of H⁺ ions. Low pH means Acidity High pH means Alkalinity Calculating pH pH = -log [H⁺] Calculating [H⁺] -pH [H⁺] = 10 What does an acid/base reaction involve? Transfer of the H⁺ from the acid to the base. Strong acid Fully dissociate...

AQA A level Chemistry 3.1.8 – Thermodynamics Questions and answers correct What are standard conditions? 298K/25°C 100kPa/1 atm 1 moldm-3 Enthalpy change of formation The enthalpy change when 1 mole of a compound is formed from its constituent elements under standard conditions, with all reactants and products in their standard states. Enthalpy change of combustion The enthalpy change when 1 mole of a substance is burned completely in oxygen. Enthalpy change of atom...

Aqa A level Chemistry Energetics Definitions and Formulas Questions and Answers Standard Enthalpy Of Formation The enthalpy change that takes place when one mole of a compound is formed from its constituent elements under standard conditions; all products and reactants in their standard states Standard Enthalpy Of Combustion The enthalpy change that takes place when one mole of a compound completely reacts with oxygen under standard conditions with all reactants and products being in ...

Aqueous ions a level chemistry aqa Questions and Answers Aqueous ion formula for Iron (11) and what colour is it [Fe(H2O)6]2+ (aq) green solution Aqueous ion formula for copper (11) what colour is it [Cu(H2O)6]2+ blue solution Aqueous ion Iron (111) and what colour is it [Fe(H2O)6]3+ (aq) purple solution may look yellow-brown due to [Fe(H2O)5(OH)]2+ Aqueous ion Aluminium (111) and what colour is it [Al(H2O)6]3+(aq) colourless solution Iron (11) aqueous ion plus N...

AQA A-level Chemistry Topic 1.4 - TOF Mass Spectrometry Questions and Answers What are the two types of ionisation for a mass spectrometer? Electron impact Electrospray ionisation Describe the stages of electron impact. 1. High energy electrons are fired at the sample using an electron gun. 2. This knocks off an electron from each atom/molecule to form 1+ ions. Describe the stages of electrospray ionisation. 1. The sample is dissolved in a volatile solvent (e.g. methanol or w...