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Tests for Ions- A-Level Chemistry Questions and Answers What is used to test for carbonates? Hydrochloric acid How do you know if the test result is positive for carbonates? Bubbles of CO2 released- tested with limewater How do you test for sulphates? Add dilute HCl and barium chloride solution How do you know if the test result is positive for sulphates? White precipitate formed of barium sulphate How do you test for halides? Add nitric acid and then silver nit...

A-level AQA Chemistry Transition Metals Questions and Answers Transition Metal Metal that can form one or more stable ions with a partially filled d sub-level. Scandium isn't a TM because... Has an empty d-shell when Sc3+ Zinc isn't a TM because... Has a full d-shell when Zn2+ Which 2 TM have 1 electron in 4s sub-level to give stability? Chromium and Copper Which sub levels electrons fill up first and empty first? 4s What physical properties do they...

AQA A LEVEL CHEMISTRY PAPER 1 Question and Answers TOF steps 1) ionisation 2) acceleration 3) ion drift 4) detection 5) analysis Electron impact Sample vaporised and electron gun fires high energy electrons at it which knock off 1 electron from each particle, making them 1+ ions NB- can knock off more than one e or break molecular ion electrospray ionization Sample dissolved in volatile solvent then injected through needle to give fine mist which is attached to positive en...

Practical’s Chemistry AQA A-level Questions and Answers Required Practical 1 - titration and making a standard solution Making a standard solution 1. weigh the required mass of solid using a sample bottle on a 2 dp balance. 2. transfer the solid into a beaker using distilled water to wash it out- preventing any solid remaining in the sample bottle. 3. reweigh the sample bottle and work out the difference. 4. Add 100cm3 of distilled water to the beaker to dissolve the solid (small...

OCR A Level Chemistry Transition metal colours [Cu(H2O)6]2+ Pale blue Solution [Fe(H2O)6]2+ Pale green solution [Fe(H2O)6]3+ Yellow Solution [Mn(H2O)6]2+ Pale Pink Solution [Cr(H2O)6]3+ Pale Purple Solution Cu(OH)2 Pale Blue PPT Fe(OH)2 Green PPT which darkens on standing Fe(OH)3 Orange Brown PPT Mn(OH)2 Light brown PPT which darkens on standing Cr(OH)3 Grey-green PPT [Cr(OH)6]3- Dark green solution Cr2O7 2-...

AQA A-Level Chemistry - Amount of Substance Questions and Answers Relative Atomic Mass The average mass of an atom of an element, compared to that of the mass of 1/12th of the average mass of an atom of carbon-12 Relative Molecular Mass The average mass of one molecule compared to 1/12th of the mass of one atom of carbon-12 Avogadro Constant The number of particles in one mole of an atom: 6.022 x 10^23 Solvent A liquid that can have a substance dissolved into it ...

AQA A Level Chemistry- Inorganic chemistry Questions and Answers Periodic table Table that provides chemists with a structural organisation of the known chemical elements that can be used to deduce physical and chemical properties Atomic radius across Period 3 Decreases First ionisation energy across Period 3 Increases Exceptions: Drops at Al and S Melting points across Period 3 Increases from Na to Si Decreases from Si to Ar Small rise at S Explain why the me...

AQA A level - Organic Chemistry Questions and Answers Organic compounds Compounds that contain a chain of carbon atoms Number of electrons in carbons outer shell 4 so can form 4 covalent bonds Carbon-Carbon bonds are... non-polar and relatively strong Empirical formula the simplest whole number ratio of atoms of each element in a compound molecular formula a formula that tells us the actual number of atoms of each different element in a compound structura...

A-Level Chemistry Paper 1 Definitions Questions and Answers Orbital A region around the nucleus that can hold up to two electrons with opposite spins First Ionisation Energy The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms Ionic bonding The electrostatic attraction between positive and negative ions Covalent bonding The strong electrostatic force of attraction between a shared pair of electrons and the nuclei of the bonded atoms Dati...

AQA A Level Chemistry Required Practical 10 Questions and Answers Why is the minimum volume of solvent used ? To make a saturated solution To increase the yield of the compound (enable crystallisation on cooling) Why do you hot filter the solution ? Remove insoluble impurities Prevent crystals reforming Why do you need to cool the beaker solution in ice ? Crystals reform (ice increases yield) Soluble impurities in solution Why use suction filtration ? The water pum...

OCR Chemistry A-Level - Modules 1-4 Questions and Answers what is water of crystallisation? water molecules that make up part of the crystal structure of a solid define relative isotopic mass the ass of an atom of an isotope of an element relative to one twelfth the mass of an atom of C-12 why is relative atomic mass written as a decimal? it is a weighted average mass define molecular formula the actual number of atoms of each element in a compound define what...

AQA A Level Chemistry - Shapes of Molecules Questions and Answers V-Shaped 118 2 bonding pairs, 1 lone pair, 118 Tetrahedral 4 bonding pairs, 0 lone pairs, 109.5 Pyramidal 3 bonding pairs, 1 lone pair, 107 V-Shaped 104.5 2 bonding pairs, 2 lone pairs, 104.5 Trigonal Bipyramid 5 bonding pairs, 0 lone pairs, 120 + 90

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 ...