Name the change of state that produced the first oceans.

Condensation of water vapour into liquid water produced the oceans.

Explain why oceans could not form while the Earth's surface was still very hot.

The temperature was above the boiling point of water, so all the water stayed as vapour.

State where the water vapour that formed the oceans came from.

It was released into the atmosphere by volcanic activity.

Describe how the amount of water vapour in the atmosphere changed as the oceans formed.

The amount of water vapour fell sharply as it condensed out of the atmosphere.

Explain how the formation of the oceans reduced the amount of carbon dioxide in the atmosphere.

Carbon dioxide is soluble in water, so large amounts of it dissolved into the newly formed oceans.

Edexcel GCSE Combined Science Chemistry 1SC0

Key Concepts in Chemistry

Topic overview Formulae, word equations and balanced equations Hazard symbols and assessing risk The changing model of the atom Protons, neutrons and electrons The nucleus, mass number and atomic mass Elements and isotopes Calculating particle numbers and relative atomic mass Mendeleev's periodic table How the modern periodic table is arranged Electronic configuration and the periodic table How ionic bonds form Ions in ionic compounds Formulae of ionic compounds and ionic equations Naming compounds and the ionic lattice Covalent bonds and molecules Dot and cross diagrams for simple molecules Classifying substances and the properties of ionic compounds Properties of simple molecular substances, and forms of carbon Graphite and diamond Fullerenes and graphene Polymers and models of bonding The properties of metals Relative formula mass and percentage composition Empirical and molecular formulae Conservation of mass in closed and open systems Reacting masses from balanced equations Concentration in grams per cubic decimetre Moles and the Avogadro constant Limiting reactants and stoichiometry

States of Matter and Mixtures

Topic overview The three states of matter and changes of state Energy changes during changes of state, and predicting state Pure substances and melting point data Choosing a separation technique Separating a mixture in practice Paper chromatography and interpreting a chromatogram Investigating inks by distillation and chromatography Making water potable

Chemical Changes

Topic overview Acids, alkalis and the pH scale Indicators: litmus, methyl orange and phenolphthalein Hydrogen ion concentration and the pH scale Investigating pH change when neutralising an acid Dilute and concentrated, weak and strong acids Bases and alkalis Reactions of acids, and testing for hydrogen and carbon dioxide Neutralisation and its ionic equation Preparing soluble salts from insoluble and soluble reactants Preparing pure, dry copper sulfate crystals Carrying out an acid-alkali titration Solubility rules Predicting precipitates and preparing an insoluble salt Electrolytes and what electrolysis is Movement of ions and predicting the products of molten electrolysis Electrolysis with inert electrodes Writing half equations Oxidation and reduction at the electrodes Electrolysis of copper sulfate solution Investigating the electrolysis of copper sulfate

Extracting Metals and Equilibria

Topic overview Investigating the reactivity of metals Displacement reactions as redox reactions The reactivity series Ores, oxidation and reduction Choosing a method to extract a metal Biological methods of metal extraction Corrosion resistance and recycling metals Life cycle assessment Reversible reactions and dynamic equilibrium The Haber process and its conditions Changing the position of an equilibrium

Groups in the Periodic Table

Topic overview The groups of the periodic table, and the alkali metals Reactions of the alkali metals with water The pattern in alkali metal reactivity and why it happens Physical properties of the halogens The test for chlorine, and halogens reacting with metals Hydrogen halides, and explaining halogen reactivity Displacement reactions of the halogens Group 0: the noble gases

Rates of Reaction and Energy Changes

Topic overview Investigating the rate of a reaction Measuring rate and interpreting rate graphs Collision theory and factors affecting rate Catalysts and enzymes Exothermic and endothermic changes Bond breaking, bond making and the overall energy change Bond energies, activation energy and reaction profiles

Fuels and Earth Science

Topic overview Hydrocarbons and crude oil Fractional distillation and the fractions Properties of the fractions and homologous series Complete and incomplete combustion Carbon monoxide and soot Pollutants and acid rain Hydrogen and fossil fuels compared Cracking and why it is necessary The Earth's early atmosphere How the oceans formed and how oxygen appeared The test for oxygen and the greenhouse gases Today's atmosphere and evidence for climate change

Fuels and Earth Science

How the oceans formed and how oxygen appeared

3 things to know
Paper 4

Overview

How condensing water vapour formed the oceans, how dissolved carbon dioxide was locked into carbonate sediments, limestone and fossil fuels, and how photosynthesis by primitive plants gradually removed carbon dioxide and added oxygen.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

Explain how the first oceans formed and why they could not appear while the surface was still very hot.

Key term

Give the word equation for photosynthesis and explain how it changed the early atmosphere and allowed animals to evolve.

Key term

Explain how the Earth's oceans formed.

Questions from this subtopic

Each one with the model answer underneath.

1
Explain how the Earth's oceans formed.
Model answer
As the Earth cooled, water vapour in the atmosphere condensed into liquid water, which collected in hollows in the surface.
2
Name the change of state that produced the first oceans.
Model answer
Condensation of water vapour into liquid water produced the oceans.
3
Explain why oceans could not form while the Earth's surface was still very hot.
Model answer
The temperature was above the boiling point of water, so all the water stayed as vapour.
4
State where the water vapour that formed the oceans came from.
Model answer
It was released into the atmosphere by volcanic activity.
5
Describe how the amount of water vapour in the atmosphere changed as the oceans formed.
Model answer
The amount of water vapour fell sharply as it condensed out of the atmosphere.
6
Explain how the formation of the oceans reduced the amount of carbon dioxide in the atmosphere.
Model answer
Carbon dioxide is soluble in water, so large amounts of it dissolved into the newly formed oceans.

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Key Concepts in Chemistry

States of Matter and Mixtures

Chemical Changes

Extracting Metals and Equilibria

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Hydrogen is formed.

chloridebromideiodide

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AChlorine is a pale green gas at room temperature.

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