Key term
AQA GCSE Chemistry 8462
Atomic Structure and the Periodic Table
Topic overviewAtoms, elements and compoundsWord equations, symbols and balanced equationsMixturesFrom the plum pudding model to the nuclear modelBohr, Chadwick and the modern model of the atomRelative electrical charges of subatomic particlesSize and mass of atomsRelative atomic mass and electronic structureThe periodic tableDevelopment of the periodic tableMetals and non-metalsGroup 0Group 1Group 7Transition metals, and how they differ from Group 1
Bonding, Structure, and the Properties of Matter
Topic overviewChemical bonds, including metallic bondingIonic bondingIonic compoundsCovalent bonding and how it is representedThe three states of matter and changes of statePredicting state, state symbols, and the limits of the particle modelProperties of ionic compoundsProperties of small moleculesPolymers and giant covalent structuresProperties of metals and alloys, and why metals conductDiamond and graphiteGraphene and fullerenesSizes of particles and their propertiesUses of nanoparticles
Chemical Analysis
Chemical Changes
Topic overviewThe reactivity seriesMetal oxides, extraction, and redox in terms of electronsAcids reacting with metals, neutralisation and saltsSoluble saltsThe pH scale and neutralisationTitrationsThe process of electrolysis, and molten ionic compoundsUsing electrolysis to extract metalsElectrolysis of aqueous solutions
Chemistry of the Atmosphere
Topic overviewThe Earth's early atmosphereHow oxygen increased and carbon dioxide decreasedThe gases in today's atmosphere, and which are greenhouse gasesHuman activities which contribute to an increase in greenhouse gases in the atmosphereGlobal climate change and carbon footprintsAtmospheric pollutants from fuels, and their effects
Energy Changes
Organic Chemistry
Topic overviewCrude oil, hydrocarbons and alkanesFractional distillation and petrochemicalsProperties of hydrocarbonsCracking, and testing alkenes with bromine waterWhy cracking is useful, and equations for itStructure and formulae of alkenesReactions of alkenesAlcoholsCarboxylic acidsAddition polymerisationAmino acids, DNA and naturally occurring polymers
Quantitative Chemistry
The Rate and Extent of Chemical Change
Using Resources
Topic overviewUsing the Earth's resources and sustainable developmentProducing potable water in the UKDesalination, and analysing water samplesWaste water treatmentLife cycle assessmentWays of reducing the use of resourcesCorrosion and its preventionAlloys as useful materialsGlass, clay ceramics and polymersComposites, and comparing materialsThe Haber processProduction and uses of NPK fertilisers
Quantitative Chemistry
- 5 subtopics
- 15 things to know
- Paper 1
What Quantitative Chemistry covers
Quantitative Chemistry is examined in Chemistry Paper 1. It covers conservation of mass and balanced chemical equations, relative formula mass and concentration of solutions, mass changes when a gas is involved, and measurement uncertainty, percentage yield and atom economy.
Where it is assessed
Paper 1
Chemistry Paper 1: 1 hour 45 minutes, 100 marks, 50% of the GCSE.
Check the AQA specification ↗The 5 subtopics
Each one has its own page.
- Conservation of mass and balanced chemical equationsThe law of conservation of mass, calculating masses in sealed reactions, why reactions are shown by balanced equations, balancing the equations for hydrogen and methane burning, the difference between balancing numbers and subscripts, and counting atoms in formulae such as 3H₂SO₄ and 2Ca(OH)₂.Open →
- Relative formula mass and concentration of solutionsDefining and calculating relative formula mass, showing both sides of a balanced equation total the same, percentage by mass of an element, and concentration in g/dm³ from the mass of solute and the volume of solution.Open →
- Mass changes when a gas is involved, and measurement uncertaintyWhy a metal gains mass when heated in air and a carbonate loses mass when decomposed, apparent breaches of conservation of mass explained with particles, the effect of sealing the container, uncertainty from the range of repeats, accuracy, precision, repeatability and reproducibility, random and systematic errors, anomalous results, resolution and reading scales, and mean, median and mode.Open →
- Percentage yieldWhy the theoretical mass of product is not always obtained, including reversible reactions, losses during separation and side reactions, the meaning of yield and percentage yield, the percentage yield equation and why it cannot exceed 100%, and worked percentage yield calculations.Open →
- Atom economyWhat atom economy measures and why a high value matters for sustainability and cost, the information and equation needed to calculate it, why a reaction with a single product has 100% atom economy, and worked calculations for calcium oxide, iron and zinc oxide.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Numbers
Give the unit of concentration by mass, how to calculate it, and the mass of solute in 250 cm³ of 40 g/dm³ solution.
Key term
24 g of magnesium reacts completely with oxygen to form 40 g of magnesium oxide. What mass of oxygen reacted?
Key term
No atoms are gained or lost in a reaction, so why is the calculated mass of product not always obtained?
Key term
Explain why using reactions with a high atom economy matters for sustainable development.
Key term
Explain why the total mass inside a sealed container does not change when a reaction happens in it.
Numbers
Calculate the percentage by mass of oxygen in CO₂, given relative atomic masses C = 12 and O = 16.
Key term
Explain why the mass of solid increases when a metal is heated in an open crucible in air.
Key term
Give three reasons why the full theoretical mass of a product may not be obtained.
Key term
Give an economic reason for choosing a reaction with a high atom economy.
Key term
Give the balancing numbers needed for the equation H₂ + O₂ → H₂O.
Numbers
Calculate the percentage by mass of nitrogen in NH₄NO₃, given relative atomic masses N = 14, H = 1 and O = 16.
Key term
Explain why the mass of solid falls when a metal carbonate is thermally decomposed in an open container.
Process
Name a stage of a preparation at which product is commonly lost.
Key term
What information is needed before the atom economy of a reaction can be calculated?
Take Quantitative Chemistry further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Percentage yield vs Atom economy
Percentage yield: product actually obtained as a share of the maximum theoretical amount. Atom economy: the share of reactant formula mass that ends up in the desired product.
Balancing number vs Subscript
Balancing number: the figure in front of a formula that multiplies the whole formula. Subscript: the small figure inside a formula that multiplies only the atom before it.
Questions from this topic
Each one with the model answer underneath.
- 1
State the law of conservation of mass.
Model answer
No atoms are lost or made during a chemical reaction, so the total mass of the products equals the total mass of the reactants.
- 2
In a reaction carried out in a sealed flask, 8 g of one reactant reacts completely with 12 g of another to give a single product. What mass of product forms?
Model answer
20 g, because the mass of the product must equal the total mass of the reactants.
- 3
24 g of magnesium reacts completely with oxygen to form 40 g of magnesium oxide. What mass of oxygen reacted?
Model answer
16 g, since the mass of the product equals the total mass of the reactants.
- 4
Explain why the total mass inside a sealed container does not change when a reaction happens in it.
Model answer
The atoms present are only rearranged into new substances, and none are lost or made, so the total mass stays the same.
- 5
Explain why chemical reactions can be represented by balanced symbol equations.
Model answer
Because no atoms are lost or made, the number of atoms of each element must be the same on both sides of the equation.
- 6
What does it mean to say that a symbol equation is balanced?
Model answer
There are the same numbers of atoms of each element on the left-hand side as on the right-hand side.
What is inside Levo
Six ways to work the same material.
Quantitative Chemistry revision questions
- What does Quantitative Chemistry cover in AQA GCSE Chemistry?
- 5 subtopics: conservation of mass and balanced chemical equations, relative formula mass and concentration of solutions, mass changes when a gas is involved, and measurement uncertainty, percentage yield and atom economy. Each one has its own page with questions and model answers.
- How is Quantitative Chemistry organised?
- By the AQA 8462 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Quantitative Chemistry, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
Or £46 a year, about £3.83 a month. Cancel anytime.