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Define the term relative atomic mass (2 marks). - Correct Ans-. 1. The average mass of an atom of an element (average mass of all isotopes of an element) 2. Compared to 1/12th the mass of an atom of carbon-12 Describe how molecules are ionised using electrospray ionisation (4 marks). - Correct Ans-1. Sample dissolved (in a volatile solvent) (allow named solvent eg water or methanol) 2. (injected through) a needle or nozzle or capillary and at high voltage/4000 volts or high...

AQA Chemistry A level

AQA A LEVEL CHEMISTRY PAPER 1 Questions and Answers 100% Solved Hydrogen fuel cell advantages and disadvantages + less pollution + greater efficiency (less heat energy wasted) - expensive - safety issues storing and transporting H2 - H2 produced by electrolysis of water (uses electricity) What happens if current flows in an electrochemical cell? -reactions occur separately at each electrode -voltage falls to zero as reactants used up

AQA A-Level Chemistry - Amount of Substance, Amount of Substance - AQA ALevel Chemistry Questions and Answers Why is Percentage Yield never 100%? -Loss by mechanical transfer (e.g. when moving from one container to another) -Loss during separation (e.g. filtration) -Reaction not completing -Side reaction Calculating Moles of a Solvent Dissolved in a Solution Moles = (solution volume(cm^3) x concentration(mol/dm^3))/1000

AQA A LEVEL Chemistry Questions with Complete Solutions Oxidising agent for oxidation of alcohols Acidified potassium dichromate Orange (Cr2O7 2-) to green(Cr 3+) What happens when an unsymmetrical alcohol undergoes and elimination reaction A mixture of isomeric products are produced

AQA A Level Chemistry Definitions Questions with Complete Solutions Disproportionation The oxidation and reduction of the same element in a redox reaction Dynamic Equilibrium The equilibrium that exists in a closed system when the rate of the forward reaction is equal to the rate of the reverse reaction E/Z Isomerism A type of stereoisomerism in which different groups attached to each carbon of a C=C double bond may be arranged differently in space because of the restricted rotation of ...

AQA Chemistry A level Questions and Answers 100% Solved what is a lewis acid electron pair acceptor (metal ion) what is a lewis base electron pair donor (ligand) colour of hexaaqua iron (II) green colour of hexaaqua copper (II) blue

AQA Chemistry A level exam 2024

What is the relative mass and charge on a proton? Mass 1 charge +1 What is the relative mass and charge on a neutron? Mass 1 Charge 0 What is the relative mass and charge on an electron? Mass 1/2000 Charge -1 What is the mass number? The total number of protons and neutrons in the nucleus of an atom What is the Atomic (proton) number? This is the number of protons in the nucleus of an atom and is used to identify an element What are Ions? Ion have different numbers of protons and electrons....

AQA CHEMISTRY A LEVEL WITH COMPLETE SOLUTIONS covalent bond - ANSWER-a shared pair of electrons between non-metal elements co-ordinate bond - ANSWER-a shared pair of electrons where both electrons are supplied by one atom repulsion in shapes of molecules - ANSWER-Lone pair-lone pair > lone pair-bonding pair > bonding pair-bonding pair electronegativity - ANSWER-the power of an atom to attract the pair of electrons in a covalent bond hess' law - ANSWER-Total enthalpy chang...