THE EARTH’S ATMOSPHERE A guide for GCSE students 2010 SPECIFICATIONS KNOCKHARDY PUBLISHING

THE EARTH’S ATMOSPHERE INTRODUCTION This Powerpoint show is one of several produced to help students understand selected GCSE Chemistry topics. It is based on the requirements of the AQA specification but is suitable for other examination boards. Individual students may use the material at home for revision purposes and it can also prove useful for classroom teaching with an interactive white board. Accompanying notes on this, and the full range of AS and A2 Chemistry topics, are available from the KNOCKHARDY WEBSITE at... All diagrams, photographs and any animations in this Powerpoint are original and created by Jonathan Hopton. Permission must be obtained for their use in any work that is distributed for financial gain.

CONTENTS CONTENTS Preparatory work Today’s atmosphere Fractional distillation of air Composition of air – laboratory experiment How the atmosphere has changed over time The Miller-Urey experiment Carbon dioxide in the atmosphere THE EARTH’S ATMOSPHERE

THE ATMOSPHERE PREPARATORY WORK

THE ATMOSPHERE PREPARATORY WORK Arrange the following gases into ELEMENTS, COMPOUNDS and MIXTURES CARBON DIOXIDE AMMONIA WATER (VAPOUR) AIR OXYGEN ARGON NITROGEN HYDROGEN

THE ATMOSPHERE PREPARATORY WORK Arrange the following gases into ELEMENTS, COMPOUNDS and MIXTURES CARBON DIOXIDE AMMONIA WATER (VAPOUR) AIR OXYGEN ARGON NITROGEN HYDROGEN ELEMENTS COMPOUNDS MIXTURES

THE ATMOSPHERE PREPARATORY WORK Arrange the following into ELEMENTS, COMPOUNDS and MIXTURES

THE ATMOSPHERE PREPARATORY WORK Arrange the following into ELEMENTS, COMPOUNDS and MIXTURES ELEMENTS COMPOUNDS MIXTURES

THE ATMOSPHERE PREPARATORY WORK All these gases have been in the earth’s atmosphere. How many of them… were there originally / are there now? CARBON DIOXIDE AMMONIA WATER VAPOUR OXYGEN ARGON NITROGEN HELIUM OZONE METHANE HYDROGEN

THE ATMOSPHERE PREPARATORY WORK CARBON DIOXIDE AMMONIA WATER VAPOUR OXYGEN ARGON NITROGEN HELIUM OZONE METHANE ORIGINAL PRESENT CARBON DIOXIDE WATER VAPOUR All these gases have been in the earth’s atmosphere. How many of them… were there originally / are there now?

THE ATMOSPHERE PREPARATORY WORK Which of the following gases are classed as atmospheric pollutants? CARBON DIOXIDE WATER VAPOUR OXYGEN ARGON NITROGEN CARBON MONOXIDE NITROGEN MONOXIDE SULPHUR DIOXIDE

THE ATMOSPHERE PREPARATORY WORK Which of the following gases are classed as atmospheric pollutants? CARBON DIOXIDE WATER VAPOUR OXYGEN ARGON NITROGENCARBON MONOXIDE NITROGEN MONOXIDE SULPHUR DIOXIDE NON-POLLUTANTSPOLLUTANTS

THE EARTH IS COVERED BY A THIN LAYER OF ATMOSPHERE MADE UP OF A MIXTURE OF GASES THE ATMOSPHERE TODAY

THE MOST COMMON GASES IN THE ATMOSPHERE ARE

THE ATMOSPHERE TODAY THE MOST COMMON GASES IN THE ATMOSPHERE ARE NITROGEN

THE ATMOSPHERE TODAY THE MOST COMMON GASES IN THE ATMOSPHERE ARE NITROGEN OXYGEN

ESTIMATE THE PERCENTAGES THE ATMOSPHERE TODAY NITROGEN OXYGEN OTHER GASES (MOSTLY ARGON) THE MOST COMMON GASES IN THE ATMOSPHERE ARE

NITROGEN OXYGEN OTHER GASES (MOSTLY ARGON) 78%78% 21%21% 1%1% THE ATMOSPHERE TODAY THE MOST COMMON GASES IN THE ATMOSPHERE ARE

Air is a mixture of various gases ATMOSPHERIC GASES - SUMMARY

Air is a mixture of various gases Its composition can vary depending on the environment. If one ignoreswater vapour0% - 4% pollutants(variable) ATMOSPHERIC GASES - SUMMARY

Air is a mixture of various gases Its composition can vary depending on the environment. If one ignoreswater vapour0% - 4% pollutants(variable) the main constituents arenitrogen78% oxygen21% noble gases* 1% carbon dioxide0.03% * mostly argon but with some helium, neon, krypton and xenon The gases in air have different boiling points and can be fractionally distilled to provide a source of raw materials used in a variety of Industrial processes. ATMOSPHERIC GASES - SUMMARY

FRACTIONAL DISTILLATION OF AIR

The gases in air have different boiling points and can be fractionally distilled to provide useful raw materials used in industrial processes. FRACTIONAL DISTILLATION OF AIR

The gases in air have different boiling points and can be fractionally distilled to provide useful raw materials used in industrial processes. FRACTIONAL DISTILLATION OF AIR Air is filtered to remove dust Water vapour condenses, and is removed using absorbent filters Carbon dioxide freezes at –79ºC, and is removed The remaining air is cooled in stages to –200°C where it is a liquid The liquid is then allowed to warm up Nitrogen boils off first at –196ºC Oxygen boils off at –183ºC Air

The gases in air have different boiling points and can be fractionally distilled to provide useful raw materials used in industrial processes. FRACTIONAL DISTILLATION OF AIR Air is filtered to remove dust Water vapour condenses, and is removed using absorbent filters Carbon dioxide freezes at –79ºC, and is removed The remaining air is cooled in stages to –200°C where it is a liquid The liquid is then allowed to warm up Nitrogen boils off first at –196ºC Oxygen boils off at –183ºC

The gases in air have different boiling points and can be fractionally distilled to provide useful raw materials used in industrial processes. FRACTIONAL DISTILLATION OF AIR Air is filtered to remove dust Water vapour condenses, and is removed using absorbent filters Carbon dioxide freezes at –79ºC, and is removed The remaining air is cooled in stages to –200°C where it is a liquid The liquid is then allowed to warm up Nitrogen boils off first at –196ºC Oxygen boils off at –183ºC CO 2

The gases in air have different boiling points and can be fractionally distilled to provide useful raw materials used in industrial processes. FRACTIONAL DISTILLATION OF AIR Air is filtered to remove dust Water vapour condenses, and is removed using absorbent filters Carbon dioxide freezes at –79ºC, and is removed The remaining air is cooled in stages to –200°C where it is a liquid The liquid is then allowed to warm up Nitrogen boils off first at –196ºC Oxygen boils off at –183ºC

The gases in air have different boiling points and can be fractionally distilled to provide useful raw materials used in industrial processes. FRACTIONAL DISTILLATION OF AIR Air is filtered to remove dust Water vapour condenses, and is removed using absorbent filters Carbon dioxide freezes at –79ºC, and is removed The remaining air is cooled in stages to –200°C where it is a liquid The liquid is then allowed to warm up Nitrogen boils off first at –196ºC Oxygen boils off at –183ºC

The gases in air have different boiling points and can be fractionally distilled to provide useful raw materials used in industrial processes. FRACTIONAL DISTILLATION OF AIR Air is filtered to remove dust Water vapour condenses, and is removed using absorbent filters Carbon dioxide freezes at –79ºC, and is removed The remaining air is cooled in stages to –200°C where it is a liquid The liquid is then allowed to warm up Nitrogen boils off first at –196ºC Oxygen boils off at –183ºC N2N2

The gases in air have different boiling points and can be fractionally distilled to provide useful raw materials used in industrial processes. FRACTIONAL DISTILLATION OF AIR Air is filtered to remove dust Water vapour condenses, and is removed using absorbent filters Carbon dioxide freezes at –79ºC, and is removed The remaining air is cooled in stages to –200°C where it is a liquid The liquid is then allowed to warm up Nitrogen boils off first at –196ºC Oxygen boils off at –183ºC O2O2

The gases in air have different boiling points and can be fractionally distilled to provide useful raw materials used in industrial processes. FRACTIONAL DISTILLATION OF AIR Air is filtered to remove dust Water vapour condenses, and is removed using absorbent filters Carbon dioxide freezes at –79ºC, and is removed The remaining air is cooled in stages to –200°C where it is a liquid The liquid is then allowed to warm up Nitrogen boils off first at –196ºC Oxygen boils off at –183ºC O2O2 N2N2 CO 2 Air Argon boils off at -186ºC

USES OF THE COMPONENTS OF AIR OXYGENsteel making oxy-acetylene welding breathing equipment aerating sewage NITROGENinert atmosphere for food – stops it going ‘off’ liquid nitrogen is used for cooling medical tissue ARGONinert atmosphere for light bulbs

COMPOSITION OF AIR - LABORATORY EXPERIMENT

Place copper turnings in a silica tube and fill one of the syringes with air. Heat the copper and push the air repeatedly over it. Continue until the volume is constant. The pinkish solid turns black and the volume of air decreases. The copper reacts with about 20% of air, OXYGEN, to produce a new substance. The remaining, unreactive, 80% is mostly NITROGEN. COMPOSITION OF AIR - LABORATORY EXPERIMENT THE ANIMATION WILL START SOON

THE ATMOSPHERE ORIGIN

THE ATMOSPHERE ORIGIN During the first billion years of the earth’s existence, there was intense volcanic activity which released… GASES- this formed the original atmosphere WATER VAPOUR- which eventually condensed to form oceans

THE ATMOSPHERE ORIGIN During the first billion years of the earth’s existence, there was intense volcanic activity which released… GASES- this formed the original atmosphere WATER VAPOUR- which eventually condensed to form oceans The atmosphere was probably... mainlyCARBON DIOXIDE some WATER VAPOUR small amounts of METHANE small amounts of AMMONIA Since then it has changed considerably

THE ATMOSPHERE 4½ BILLIONS OF YEARS AGO Any atmosphere burned away 1 The earth was molten 1

THE ATMOSPHERE 4½ BILLIONS OF YEARS AGO CARBON DIOXIDE plus STEAM and a little METHANE and AMMONIA (A bit like Mars or Venus today) 2 Volcanic activity 12

THE ATMOSPHERE 4½ BILLIONS OF YEARS AGO WATER VAPOUR condensed to form the oceans. 3 The earth cooled 123

THE ATMOSPHERE 4½ BILLIONS OF YEARS AGO Atmosphere became ‘polluted’ with OXYGEN 4 Plants began to evolve; PHOTOSYNTHESIS 1234

THE ATMOSPHERE 4½ BILLIONS OF YEARS AGO CARBON DIOXIDE levels went down 5 CO 2 dissolved in oceans forming carbonates and also got ‘locked up’ in sedimentary rocks and fossils fuels 12345

THE ATMOSPHERE 4½ BILLIONS OF YEARS AGO NITROGEN and CARBON DIOXIDE were produced 6 Methane and ammonia reacted with oxygen

THE ATMOSPHERE 4½ BILLIONS OF YEARS AGO More NITROGEN produced and ammonia levels drop 7 Ammonia converted to nitrates by bacteria

THE ATMOSPHERE 4½ BILLIONS OF YEARS AGO Small decrease in OXYGEN; OZONE layer formed 8 SOME OXYGEN TURNED INTO TO OZONE WHICH FILTERED OUT HARMFUL UV RAYS AND ALLOWED MORE ORGANISMS TO EVOLVE

THE ATMOSPHERE 4½ BILLIONS OF YEARS AGO 9 Today’s atmosphere NITROGEN78% 4/5 OXYGEN21% 1/5 + NOBLE GASES CARBON DIOXIDE WATER VAPOUR

THE MILLER-UREY EXPERIMENT (1952)

Two scientists, Miller and Urey, tried to recreate the conditions which may might have occurred around 3 billion years ago.

THE MILLER-UREY EXPERIMENT (1952) Two scientists, Miller and Urey, tried to recreate the conditions which may might have occurred around 3 billion years ago. They mixed water vapour with ammonia, methane and hydrogen and passed electric sparks (to represent lightning) through the gases.

THE MILLER-UREY EXPERIMENT (1952) Two scientists, Miller and Urey, tried to recreate the conditions which may might have occurred around 3 billion years ago. They mixed water vapour with ammonia, methane and hydrogen and passed electric sparks (to represent lightning) through the gases. When they analysed the mixture they found that many carbon-based compounds had formed inside the flask. Some compounds were amino acids which can be built into proteins.

THE MILLER-UREY EXPERIMENT (1952) Two scientists, Miller and Urey, tried to recreate the conditions which may might have occurred around 3 billion years ago. They mixed water vapour with ammonia, methane and hydrogen and passed electric sparks (to represent lightning) through the gases. When they analysed the mixture they found that many carbon-based compounds had formed inside the flask. Some compounds were amino acids which can be built into proteins. The first life forms (about 3 billion years ago) may have been bacteria which were able to live on methane and ammonia. Primordial soup is a mixture of chemicals which may have given rise to life on Earth. It can be used to explain how living organisms appeared on Earth.

THE MILLER-UREY EXPERIMENT (1952) Two scientists, Miller and Urey, tried to recreate the conditions which may might have occurred around 3 billion years ago. They mixed water vapour with ammonia, methane and hydrogen and passed electric sparks (to represent lightning) through the gases. When they analysed the mixture they found that many carbon-based compounds had formed inside the flask. Some compounds were amino acids which can be built into proteins. The first life forms (about 3 billion years ago) may have been bacteria which were able to live on methane and ammonia. Primordial soup is a mixture of chemicals which may have given rise to life on Earth. It can be used to explain how living organisms appeared on Earth. HOWEVER, IT IS JUST ONE OF MANY THEORIES

THE MILLER-UREY EXPERIMENT

WATER IS HEATED GASES ARE ADDED H 2, CH 4, NH 3 WATER VAPOUR A SPARK IS APPLIED TO THE MIXTURE OF GASES THE GAS MIXTURE IS COOLED ANY LIQUID IS DRAWN OFF UNREACTED GASES ARE RECYCLED

THE MILLER-UREY EXPERIMENT WATER IS HEATED GASES ARE ADDED H 2, CH 4, NH 3 WATER VAPOUR A SPARK IS APPLIED TO THE MIXTURE OF GASES THE GAS MIXTURE IS COOLED ANY LIQUID IS DRAWN OFF UNREACTED GASES ARE RECYCLED

THE MILLER-UREY EXPERIMENT WATER IS HEATED GASES ARE ADDED H 2, CH 4, NH 3 WATER VAPOUR A SPARK IS APPLIED TO THE MIXTURE OF GASES THE GAS MIXTURE IS COOLED ANY LIQUID IS DRAWN OFF UNREACTED GASES ARE RECYCLED

THE MILLER-UREY EXPERIMENT WATER IS HEATED GASES ARE ADDED H 2, CH 4, NH 3 WATER VAPOUR A SPARK IS APPLIED TO THE MIXTURE OF GASES THE GAS MIXTURE IS COOLED ANY LIQUID IS DRAWN OFF UNREACTED GASES ARE RECYCLED

THE MILLER-UREY EXPERIMENT WATER IS HEATED GASES ARE ADDED H 2, CH 4, NH 3 WATER VAPOUR A SPARK IS APPLIED TO THE MIXTURE OF GASES THE GAS MIXTURE IS COOLED ANY LIQUID IS DRAWN OFF UNREACTED GASES ARE RECYCLED

THE MILLER-UREY EXPERIMENT WATER IS HEATED GASES ARE ADDED H 2, CH 4, NH 3 WATER VAPOUR A SPARK IS APPLIED TO THE MIXTURE OF GASES THE GAS MIXTURE IS COOLED ANY LIQUID IS DRAWN OFF UNREACTED GASES ARE RECYCLED

THE MILLER-UREY EXPERIMENT WATER IS HEATED GASES ARE ADDED H 2, CH 4, NH 3 WATER VAPOUR A SPARK IS APPLIED TO THE MIXTURE OF GASES THE GAS MIXTURE IS COOLED ANY LIQUID IS DRAWN OFF UNREACTED GASES ARE RECYCLED

THE MILLER-UREY EXPERIMENT WATER IS HEATED GASES ARE ADDED H 2, CH 4, NH 3 WATER VAPOUR A SPARK IS APPLIED TO THE MIXTURE OF GASES THE GAS MIXTURE IS COOLED ANY LIQUID IS DRAWN OFF UNREACTED GASES ARE RECYCLED

CARBON DIOXIDE IN THE ATMOSPHERE

THEN Years ago carbon dioxide got ‘locked up’ in limestone rock which had formed from the remains of shellfish. The carbon dioxide also reacted with sea water to produce insoluble carbonates which formed a sediment and soluble magnesium hydrogencarbonate and calcium hydrogencarbonate. Carbon dioxide ended up as the carbon in fossil fuels.

THEN Years ago carbon dioxide got ‘locked up’ in limestone rock which had formed from the remains of shellfish. The carbon dioxide also reacted with sea water to produce insoluble carbonates which formed a sediment and soluble magnesium hydrogencarbonate and calcium hydrogencarbonate Carbon dioxide ended up as the carbon in fossil fuels NOW Animals and humans produce carbon dioxide through respiration Plants help in removing carbon dioxide through photosynthesis. This process isn’t enough to balance the extra carbon dioxide produced by the burning of fossil fuels. The extra carbon dioxide contributes to global warming as a greenhouse gas. CARBON DIOXIDE IN THE ATMOSPHERE

CO 2 CARBON DIOXIDE IN THE ATMOSPHERE COMBUSTION PHOTOSYNTHESIS OCEANS SEDIMENTARY ROCKS AIR

THE EARTH’S ATMOSPHERE THE END © 2011 JONATHAN HOPTON & KNOCKHARDY PUBLISHING