Key term
Edexcel GCSE Combined Science Chemistry 1SC0
Key Concepts in Chemistry
Topic overviewFormulae, word equations and balanced equationsHazard symbols and assessing riskThe changing model of the atomProtons, neutrons and electronsThe nucleus, mass number and atomic massElements and isotopesCalculating particle numbers and relative atomic massMendeleev's periodic tableHow the modern periodic table is arrangedElectronic configuration and the periodic tableHow ionic bonds formIons in ionic compoundsFormulae of ionic compoundsNaming compounds and the ionic latticeCovalent bonds and moleculesDot and cross diagrams for simple moleculesClassifying substances and the properties of ionic compoundsProperties of simple molecular substances, and forms of carbonGraphite and diamondFullerenes and graphenePolymers and models of bondingThe properties of metalsRelative formula mass and percentage compositionEmpirical and molecular formulaeConservation of mass in closed and open systemsReacting masses from balanced equationsConcentration in grams per cubic decimetre
States of Matter and Mixtures
Topic overviewThe three states of matter and changes of stateEnergy changes during changes of state, and predicting statePure substances and melting point dataChoosing a separation techniqueSeparating a mixture in practicePaper chromatography and interpreting a chromatogramInvestigating inks by distillation and chromatographyMaking water potable
Chemical Changes
Topic overviewAcids, alkalis and the pH scaleIndicators: litmus, methyl orange and phenolphthaleinInvestigating pH change when neutralising an acidBases and alkalisReactions of acids, and testing for hydrogen and carbon dioxideNeutralisation and its ionic equationPreparing soluble salts from insoluble and soluble reactantsPreparing pure, dry copper sulfate crystalsCarrying out an acid-alkali titrationSolubility rulesPredicting precipitates and preparing an insoluble saltElectrolytes and what electrolysis isMovement of ions and predicting the products of molten electrolysisElectrolysis with inert electrodesElectrolysis of copper sulfate solutionInvestigating the electrolysis of copper sulfate
Extracting Metals and Equilibria
Groups in the Periodic Table
Topic overviewThe groups of the periodic table, and the alkali metalsReactions of the alkali metals with waterThe pattern in alkali metal reactivity and why it happensPhysical properties of the halogensThe test for chlorine, and halogens reacting with metalsHydrogen halides, and explaining halogen reactivityDisplacement reactions of the halogensGroup 0: the noble gases
Rates of Reaction and Energy Changes
Fuels and Earth Science
Topic overviewHydrocarbons and crude oilFractional distillation and the fractionsProperties of the fractions and homologous seriesComplete and incomplete combustionCarbon monoxide and sootPollutants and acid rainHydrogen and fossil fuels comparedCracking and why it is necessaryThe Earth's early atmosphereHow the oceans formed and how oxygen appearedThe test for oxygen and the greenhouse gasesToday's atmosphere and evidence for climate change
Rates of Reaction and Energy Changes
Collision theory and factors affecting rate
- 3 things to know
- Paper 4
Overview
The conditions for a successful collision, collision frequency and energy, how temperature, concentration, surface area and pressure affect rate, why reactions slow as reactants are used up, and calculating surface area to volume ratios.
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Explain in terms of collisions how pressure, powdering a solid and cooling affect rate, and why pressure does not affect solutions.
Key term
State the two conditions that must be met for reactant particles to react.
Questions from this subtopic
Each one with the model answer underneath.
- 1
State the two conditions that must be met for reactant particles to react.
Model answer
The particles must collide with one another, and they must collide with enough energy.
- 2
What name is given to the explanation that reactions happen when particles collide?
Model answer
Collision theory.
- 3
State the two ways in which the rate of a reaction can be increased in terms of collisions.
Model answer
Either the frequency of collisions is increased, or the energy of the collisions is increased.
- 4
What is meant by the frequency of collisions?
Model answer
It is the number of collisions that happen each second.
- 5
Explain why not every collision between reactant particles causes a reaction.
Model answer
A collision only leads to a reaction if the colliding particles have at least the minimum energy needed.
- 6
A reaction mixture gradually slows down as it is left. Explain this in terms of collisions.
Model answer
The reactants are being used up, so fewer particles remain and collisions become less frequent.
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