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
States of Matter and Mixtures
Separating a mixture in practice
- 3 things to know
- Paper 3
Overview
Choosing filtration, crystallisation, chromatography or fractional distillation for sand and water, copper sulfate, sand and salt, pen dyes and ethanol and water, and how to obtain pure water from muddy salt water.
What you need to know
Answer each one before you reveal it.
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Key term
Describe how to obtain copper sulfate crystals from copper sulfate solution.
Key term
A mixture contains sand and salt. Describe how to obtain dry salt from it.
Questions from this subtopic
Each one with the model answer underneath.
- 1
Which technique separates sand from a mixture of sand and water?
Model answer
Filtration, because sand is an insoluble solid.
- 2
Describe how to obtain copper sulfate crystals from copper sulfate solution.
Model answer
Heat the solution to evaporate some of the water, then leave the concentrated solution to cool so that crystals form.
- 3
A mixture contains sand and salt. Describe how to obtain dry salt from it.
Model answer
Add water and stir to dissolve the salt, filter off the sand, then crystallise the salt from the filtrate.
- 4
Which technique would you use to find out how many coloured dyes are in a felt-tip pen?
Model answer
Paper chromatography.
- 5
Suggest how to separate a mixture of ethanol and water.
Model answer
Use fractional distillation, because the two liquids mix together and have different boiling points.
- 6
What properties of the components do you need to know before choosing a separation technique?
Model answer
Properties such as solubility, boiling point and whether each component is a solid or a liquid.
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