Key term
Edexcel A-Level Chemistry 9CH0
Atomic Structure and the Periodic Table
Bonding and Structure
Inorganic Chemistry and the Periodic Table
Topic overviewFlame tests and how they workThermal decomposition of nitrates and carbonatesCarrying out flame tests and testing the gasesGroup 2 elements and their compoundsTrends in Group 7 and predicting fluorine and astatineHalogen displacement reactionsDisproportionation and the reactions of chlorineHalides with concentrated sulfuric acid, and the hydrogen halidesTesting for halide ions with silver nitrateTesting for carbonate and hydrogencarbonate ionsTesting for sulfate and ammonium ions
Formulae, Equations and Amounts of Substance
Topic overviewThe mole, molar mass and empirical formulaThe ideal gas equation and molar volumeEquations, concentration and reacting quantitiesStandard solutions, titration and uncertaintyPercentage yield, atom economy and acid reactionsCore practicals 1 to 3Empirical formula and water of crystallisation by experimentApparatus, uncertainty and mathematical skills
Organic Chemistry I
Topic overviewFormulae, homologous series and functional groupsIUPAC nomenclatureTypes of organic reaction and structural isomerismStereoisomerism and E/Z nomenclaturePractical techniques in organic chemistryAlkanes, crude oil and combustion pollutantsRadical substitutionAlkenes, the double bond and hydrogenationElectrophilic addition, Markovnikov's rule and the test for an alkeneAddition polymers and waste polymersNucleophilic substitution of halogenoalkanesRates of hydrolysis and the SN1 and SN2 mechanismsClassifying and oxidising alcoholsAlcohols: practical techniques and the core practicals
Modern Analytical Techniques I
Energetics I
Kinetics I
Equilibrium I
Acid-Base Equilibria
Energetics II
Redox II
Transition Metals
Topic overviewElectron configuration and what makes a transition metalComplex ions, ligands and the colour of transition metal ionsCoordination number, monodentate ligands and the shapes of complexesBidentate and multidentate ligands, and ligand exchangeVanadium and chromium chemistryReactions with sodium hydroxide and ammoniaCobalt and copper complexesLigand exchange, amphoteric behaviour and the chelate effectTransition metals as catalysts
Kinetics II
Organic Chemistry II
Topic overviewChiralityAldehydes, ketones and their oxidationReduction and nucleophilic addition of HCNTesting for a carbonyl group: 2,4-DNPH and the iodoform reactionCarboxylic acids and their reactionsEsters and acyl chloridesReflux, extraction and recrystallisationDistillation, melting temperature and working safely
Organic Chemistry III
Topic overviewThe structure of benzene and the evidence for itElectrophilic substitution of benzeneNitration, halogenation, Friedel-Crafts and phenolAmines: structure and basicityReactions of amines and preparing themAmides and condensation polymersAmino acids, zwitterions and proteinsEmpirical and molecular formulae from analytical dataGrignard reagents and multi-step synthesisPurification techniques and the aspirin preparation
Formulae, Equations and Amounts of Substance
Percentage yield, atom economy and acid reactions
- 3 things to know
- Papers 1, 2 and 3
Overview
Percentage yield and theoretical yield, atom economy and why a high value is desirable, displacement reactions, the products of acids with metals, carbonates, metal oxides and alkalis, precipitation reactions, and hazard, risk and laboratory precautions.
What you need to know
Answer each one before you reveal it.
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Numbers
State the formula for percentage yield.
Numbers
Calculate the percentage yield when actual yield = 17.4 g, theoretical yield = 20.7 g.
Questions from this subtopic
Each one with the model answer underneath.
- 1
State the formula for percentage yield.
Model answer
Percentage yield = (actual yield / theoretical yield) × 100%
- 2
Calculate the percentage yield when actual yield = 17.4 g, theoretical yield = 20.7 g.
Model answer
Percentage yield = (17.4 ÷ 20.7) × 100 = 84.1 %.
- 3
Define theoretical yield.
Model answer
Theoretical yield is the maximum mass of product that could be formed from the given amounts of reactants, assuming complete reaction.
- 4
State the formula for atom economy.
Model answer
Atom economy = (molar mass of desired product / sum of molar masses of all products) × 100%
- 5
Calculate the atom economy when molar mass of desired product = 374.6 g mol⁻¹, sum of molar masses of all products = 595.6 g mol⁻¹.
Model answer
Atom economy = (374.6 ÷ 595.6) × 100 = 62.9 %.
- 6
Why is a high atom economy desirable in a chemical reaction?
Model answer
A high atom economy means a greater proportion of reactant atoms end up in the desired product, making the reaction more efficient and sustainable.
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