233 terms

AQA GCSE Triple Science - Chemistry paper 2

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What is in the nucleus?
Protons and neutrons
What is relative atomic mass?
Relative atomic mass is an average mass taking into account the different masses and abundances of all the isotopes that make up the element
How do you calculate the relative atomic mass?
Sum of (isotope abundance x isotope mass number) / sum of abundances of all the isotopes
What are compounds?
Substances formed from two or more elements, the atoms of each are in fixed proportions throughout the compound, and they're held together by chemical bonds
What is ionic bonding?
A compound formed through bonding between a metal and non-metal (consists of ions). The metals become positive as they lose electrons, and the non-metals become negative as they lose electrons. E.g. the metal gives an electron to a chlorine atom. The oppositely charged ions are attracted to each other by electrostatic forces
What are five properties of ionic compounds?
High melting points
High boiling points (due to the strong bonds between the ions)
Cannot conduct electricity in solid form
Conduct electricity in molten form as the ions are free to move
Dissolve easily in water
What is covalent bonding?
A compound formed from non-metals consists of molecules. Each atom shares an electron with another atom.
Give an example of an ionic compound
NaCl (Sodium chloride)
Give an example of a compound that is covalently bonded
HCl (Hydrogen chloride)
What are 5 features of simple molecular structures?
Weak intermolecular forces
Low melting points
Low boiling points
Melting and boiling points increase as the molecules get bigger
Don't conduct electricity
What is the formula for carbon dioxide?
CO2
What is the formula for ammonia?
NH3
What is the formula for water?
H2O
What is the formula for sodium chloride?
NaCl
What is the formula for carbon monoxide?
CO
What is the formula for hydrochloric acid?
HCl
What is the formula for calcium chloride?
CaCl2
What is the formula for sodium carbonate?
Na2CO3
What is the formula for sulfuric acid?
H2SO4
What are mixtures?
Two or more elements not chemically bonded together
Give five methods of separating mixtures
Filtration
Crystallisation
Simple distillation
Fractional distillation
Chromatography
How do you do paper chromatography?
Draw a line near the bottom of a sheet of filter paper
Add a spot of ink to the line
The solvent seeps up the line
How do you separate a soluble salt from a solution using evaporation?
Pour the solution into an evaporating dish
Heat the solution
The solution will get more concentrated as the solvent evaporates and crystals will form
Heat until the only thing left is dry crystals
How do you separate a soluble salt from a solution using crystallisation?
Pour the solution into an evaporating dish
Heat the solution
Once some of the solution has evaporated, or when you see crystals start to form, remove from heat and allow solution to cool
The salt should for crystals as it becomes insoluble in the cold, highly concentrated solution
Filter the crystals out of the solution
How do you use filtration and crystallisation to separate rock salt?
Grind the mixture so the salt crystals dissolve easier
Dissolve the salt in water
Filter the mixture
Evaporate the water from the salt so it forms dry crystals
How do you use simple distillation to separate solutions?
The solution is heated and the part of the solution that has the lowest boiling point evaporates
The vapour is then cooled, condensed, and collected
What is an issue with simple distillation?
It can only be used to separate mixtures with very different boiling points
What method is used to separate mixtures with similar boiling points?
Fractional distillation
How do you do fractional distillation?
Put the mixture in a flask with a fractionating column on top
Heat the mixture to a certain temperature
When the temperature on the thermometer matches the boiling point of the liquid with the lowest boiling point, the first one will evaporate.
When the first fraction boils, it evaporates. It is collected through a condenser
This process is repeated at higher temperatures
How was the 'plum pudding model' of the atom formed?
At the start of the 19th century, Dalton thought atoms were solid spheres. In 1897, JJ Thomson concluded they weren't solid spheres. He believed they contains a smaller, negatively charged particle - electrons. The plum pudding model shows the atom as a ball of positive charge with electrons stuck in it
What is the alpha scattering experiment?
Rutherford set up an experiment where he fired a beam of alpha particles towards some thin gold foil. He found most of the particles went straight through the foil. This suggested that there was lots of empty space, however he noticed that some alpha particles were deflected, with a few by more than 90 degrees. This suggested that there was a concentrated positive nucleus in the centre of the atom since two positive forces repel. This led to the current model being developed as the plum pudding model thought electrons were suspended in a positive cloud.
Who suggested that all electrons were contained in shells?
Niels Bohr
What is the maximum number of electrons in each of the first three shells?
2, 8, 8
How has the periodic table developed?
Dalton suggested the periodic table was arranged by mass, measured by chemical reactions. Newlands built on this theory with the 'law of octaves'. He noticed he properties of every 8th element were similar. Dmitri Mendeleev arranged them by atomic mass, and left space for elements that were undiscovered at the time.
How many outer electrons do elements in group 1 have?
1
Give some features of group 1 metals
They react with water more vigorously as you go down the periodic table as the electrons are further away from the pull of the positive nucleus. They have low melting and boiling points compared to the other metals, and they are softer. As you go down the group, the melting point decreases, the density increases, and they become more reactive
Give some features of group 7 halogens
They become less reactive as you go down the group as the positive nucleus is needed to pull the electrons in, and this force is weaker as the shells get further away.
The halogens are: fluorine, chlorine, bromine, iodine, and astatine
They are diatomic
Roughly how much of the periodic table is metals?
75%
What are the features of most metals?
They're strong, but can be bent or hammered into different shapes
They're great at conducting heat and electricity
They have high melting and boiling points
What are five features of non-metals?
Dull looking
Brittle
Not always solids at room temperature
Don't usually conduct electricity
Usually have a lower density
What are three features of transition metals?
They can have more than one ion
They are often coloured, so compounds that contain them are colourful
They often make good catalysts
What happens when you react alkali metals with water?
They produce hydrogen gas and metal hydroxides
What types of compounds do ionic compounds form?
White solids that dissolve in water to form colourless solutions
Give an example of a reaction of an alkali metal with water
Sodium + water --> sodium hydroxide + hydrogen
2Na(s) + 2H20(l) --> 2NaOH(aq) + H2(g)
What happens when you react an alkali metal with chlorine gas?
They form white metal chloride salts
Give an example of a reaction of an alkali metal with chlorine gas
Sodium + chlorine --> sodium chloride
2Na(s) + Cl2(g) --> 2NaCl(s)
When lithium reacts with oxygen, what does it form?
Lithium oxide (Li2O)
When sodium reacts with oxygen, what does it form?
A mixture of sodium oxide (Na2O) and sodium peroxide (Na2O2)
When potassium reacts with oxygen, what does it form?
A mixture of potassium peroxide (K2O2) and potassium superoxide (KO2)
What is fluorine?
A very reactive, poisonous yellow gas
What is chlorine?
A fairly reactive, poisonous, dense green gas
What is bromine?
A dense, poisonous, red-brown volatile liquid
What is iodine?
A dark grey crystalline solid or a purple vapour
What will more reactive halogens do to less reactive ones?
Displace them
Give an example of a displacement reaction involving halogens?
Cl2(g) Pale green + 2KI(aq) --> I2(aq) Brown + 2KCI(aq)
How do the boiling point of the noble gases change as you go down the group?
Boiling points increase (greater intermolecular forces between atoms)
What are ions?
Charged particles
Why do atoms gain or lose electrons?
To gain a full outer shell
What type of ions do metals form?
Positive
What type of ions do non-metals form?
Negative
What are cations?
Positive ions
What are anions?
Negative ions
What are polymers?
Long chains of repeating units joined together by covalent bonds
What are giant covalent structures?
Macro-molecules. They have strong covalent bonds.
What are three properties of most giant covalent structures?
High melting point
High boiling point
Don't conduct electricity as they don't contain charged particles
What is the structure of diamond?
Each carbon atom forms four covalent bonds in a very rigid giant covalent structure
What is the structure of graphite?
Each carbon atom forms three covalent bonds to create layers of hexagons. Each carbon atom also has one delocalised electron
Give three properties of diamond
Really hard
Very high melting point
Doesn't conduct electricity
Give three properties of graphite
Soft and slippery due to the layers, which makes it good as a lubricating material
High melting point
Conducts electricity and thermal energy
Give three properties of graphene
Strong due to the covalent bonds
Very light so it can be added to composite materials to improve their strength without adding weight
Can conduct electricity, meaning it is used in electronics
What do fullerenes form?
Spheres and tubes
What can fullerenes be used to do?
Deliver drugs into the body as they 'cage' other molecules
Catalysts as they have a huge surface area
Lubricants
Give three features of nanotubes
Conduct electricity
Conduct heat
High tensile strength
What can nanotubes be used in?
Electronics, or to strengthen materials without adding much weight (e.g. tennis racket frames)
What does metallic bonding involve?
Delocalised electrons
Why are alloys harder than pure metals?
Different elements have different sized atoms. When elements are combined to form alloys, the different sizes make it harder for the layers to slide over each other
What three things does the strength of the force between the particles in a material depend on?
The material
The temperature
The pressure
What features do all solids have?
The particles don't move around like in a liquid or gas
They keep a definite shape and volume
The particles vibrate as they become hotter
What features do all liquids have?
They have a definite volume
They move to fit the shape of the container
They expand slightly when heated
What features do all gases have?
They don't have a definite shape
They don't have a definite volume
The particles move randomly, and get faster as it gets hotter
How do solids change to liquids?
When a solid is heated, the particles gain energy. This makes the particles vibrate more, which weakens the forces that hold the solid together. At the melting point, the particles have enough energy to break free from their positions
How do liquids change to gases?
When a liquid is heated, the particles gain more energy. This means they move faster, and can eventually break all bonds, so the liquid becomes a gas.
What are the four state symbols?
solid (s), liquid (l), gas (g), and aqueous (aq)
What are coarse particles?
Paricles with a diameter between 2500nm and 10000nm. They are also known as dust
What are fine particles?
Particles with a diameter between 100nm and 2500nm
What are nano particles?
Particles that have a diameter between 1nm and 100nm. They only contain a few hundred atoms.
What happens to the surface area to volume ratio as particles decrease in size?
The ratio increases
How do you calculate the surface area to volume ratio?
surface area / volume
Give some uses for nanoparticles
Nanomedicine
Since some nano particles conduct electricity, they can be used in electric circuits for computer chips
Silver nano particles have antibacterial properties. They can be added to polymer fibres used to make wound dressings and surgical masks
Improve moisturisers without making them very oily
How do you calculate the percentage mass of an element in a compound?
((Relative atomic mass x number of atoms of that element) / formula mass of the compound) x 100
What is one mole of a substance?
The amount of that substance that contains an Avogadro number of particles (6.02 x 10^23)
What does one mole of carbon weigh?
12g
What does one mole of carbon dioxide weigh?
44g
How do you calculate the number of moles in a given mass?
Mass in g of element or compound / molecular mass of the element or compound
What mass of carbon is there in 4 moles of carbon dioxide?
4 x 12 = 48g
Why can masses change during a reaction?
If the mass increases, it it because one reactant is a gas found in the air, and the products are solids, liquids, or aqueous. When the gas reacts to form part of the product, it gets contained in the vessel so the total mass increases.
If the mass decreases, it is because a product is a gas, so its mass cannot be accounted for.
When does a reaction stop?
When all of one of the reactants is used up
What is the limiting reactant?
The reactant that is used up
What happens if you halve the amount of limiting reactant?
It halves the amount of product formed
How much does one mole of any gas occupy at 20 degrees C?
24 dm^3
How do you calculate the volume of gas?
(Mass of gas / relative formula mass of gas) x 24
What is concentration a measure of?
How crowded things are?
How do you calculate the concentration (in g/dm^3)?
Mass of solute in g / volume of solvent in dm^3
How do you calculate the concentration (in mol/dm^3)?
Number of moles of solute in mol / volume of solvent in dm^3
How do you convert from mol/dm^3 to g/dm^3?
mass = moles x relative formula mass
How do you calculate atom economy?
(relative formula mass of desired product / relative formula mass of all reactants) x 100
How is high atom economy good?
Create less waste as there isn't as much to dispose of
Cheaper
How do you calculate the percentage yield?
(mass of product actually made / maximum theoretical mass of product) x 100
Give three reasons why the yield is never 100%
Not all reactants react to make a product (e.g. in reversible reactions)
There may be side reactions
You lose some product when you separate it from the reaction mixture
What does the pH scale measure?
How acidic or alkaline a substance is
What does a low pH number mean?
The solution is acidic
What pH number does a neutral substance have?
pH 7
How do you measure the pH of a solution?
Use an indicator
pH probe, which measures it electronically and gives a numerical value
What is an acid?
A substance that forms an aqueous solution with a pH of less than 7. They form H+ ions in water
What is a base?
A substance that will react with an acid to form a salt
What is the reaction between acids and bases called?
Neutralisation
What is the generic neutralisation equation?
Acid + base --> salt + water
H+(aq) + OH-(aq) --> H2O(l) + salt
What are titrations used for?
Find out concentrations
How do you do a titration?
If you want to find the concenration of an alkali, use a pipette and pipette filler to add a set volume of the alkali to a conical flask. Add two to three drops of indicator too. Use a funnel to fill a burette with some acid of a known concentration. Use the burette to add the acid to the alkali a bit at a time, and swirl the conical flask regularly. Go especially slowly when you think the end-point (colour change) is about to be reached. The indicator changes colour when all the alkali has been neutralised. Record the final volume of acid in the burette, and use it, along with the initial reading, to calculate the volume of acid used to neutralise the alkali.
Give three single indicators, and what colours they go in acids and alkalis
Phenolphthalein - colourless in acids, pink in alkalis
Litmus - red in acids, blue in alkalis
Methyl orange - red in acids, yellow in alkalis
What do acids produce in water?
Protons - H+ ions
What do strong acids do in water?
Ionise completely
What do weak acids do in water?
They don't fully ionise and it is a reversible reaction
When there is a decrease of 1 on the pH scale, by what factor does the concentration of H+ ions increase by?
10
What are the products of a reaction involving acid and metal oxide?
Salt and water
What are the products of a reaction involving acid and metal hydroxide?
Salt and water
What are the products of a reaction involving acid and metal carbonate?
Salt, water and carbon dioxide
What is the reactivity series?
How well a metal reacts
What is the reactivity series from most reactive to least reactive, and including carbon and hydrogen?
Potassium
Sodium
Lithium
Calcium
Magnesium
Carbon
Zinc
Iron
Hydrogen
Copper
How can metals less reactive than carbon extracted from their ores?
Reduction with carbon
What are the products when an acid is reacted with a metal?
Salt and hydrogen
What are the products when a metal is reacted with water?
Metal hydroxide and hydrogen
Which metals won't react with water?
Zinc, iron and copper
What is oxidation, in the formation of metal ore?
Gain of oxygen
What is reduction, in the extraction of metal?
Loss of oxygen
What method is used to extract metals more reactive than carbon?
Electrolysis
What is a loss of electrons called?
Oxidation
What is the gain of electrons called?
Reduction
What will a more reactive metal do to a less reactive metal that is in a compound?
Displace it
What is electrolysis?
Splitting up with electricity
What happens during electrolysis?
An electric current is passed through an electrolyte solution. The ionic compound must be dissolved so the ions are free to move. The ions move towards the electrodes, where they react, and the compound decomposes. The positive ions move towards the cathode and gain electrons (they are reduced), and the negative ions will do the opposite.
What is the half equation at the cathode with an electrolyte of lead bromide?
Pb2+ + 2e- --> Pb
What is the half equation at the anode with an electrolyte of lead bromide?
2Br- --> Br2 + 2e-
What happens at the cathode if H+ ions and metal ions are present?
Hydrogen gas is produced if the metal ions form an elemental metal that is more reactive than hydrogen. If the metal ions form an elemental metal that is less reactive than hydrogen, a solid layer of pure metal will be produced
What happens at the anode if OH- and halide ions are present?
Molecules of chlorine, bromine, or iodine will be formed. If no halide ions are present, the OH- ions from the water will be discharged and oxygen gas will be formed
What is an exothermic reaction?
It transfers energy to the surroundings, usually by heating. It is shown by a rise in temperature
Give three examples of every day exothermic reactions
Combustion
Hand warmers
Self-heating cans
Are neutralisation reactions endothermic or exothermic?
Exothermic
What is an endothermic reaction?
It takes in energy from the surroundings, and is shown by a fall in temperature.
Is thermal decomposition endothermic or exothermic?
Endothermic
Why is bond breaking endothermic?
Energy must be supplied to break existing bonds
Why is bond making exothermic?
Energy is released when new bonds are formed
What does an exothermic graph look like?
What does an endothermic graph look like?
What is an electrochemical cell?
A simple system made of two different electrodes in contact with an electrolyte. The electrodes must be able to conduct electricity, so they are usually metals. The electrolyte solution contains ions which reacts with the electrode. The chemical reaction sets up a charge difference between the electrodes, and so electricity is produced if the electrodes are connected by a wire. A voltmeter measures the voltage of the cell.
What 3 factors does the voltage of a cell depend on?
The type of electrodes used (the bigger the difference in reactivity of the electrodes, the bigger the voltage of the cell).
The electrolyte used
Using a battery or a cell
What happens in non-rechargeable batteries?
The chemical reactions that happen at the electrodes are irreversible. One of the reactants gets used up so the reaction can't happen.
What do fuel cells use to produce electrical energy?
Fuel and oxygen
What is a fuel cell?
An electrical cell that is supplied with a fuel and oxygen, and uses energy from the reaction between them to produce electrical energy efficiently.
What are hydrogen-oxygen fuel cells used for?
Vehicles
Why is using fuel cells better than conventional fuels for cars?
Fuel cell vehicles don't produce as many pollutants (greenhouse gases, nitrogen oxides, sulfur dioxide, or carbon monoxide)
Why are hydrogen-oxygen fuel cells better than batteries?
Batteries are more polluting to dispose of as they are made of highly toxic metal compounds
Whilst batteries in electric vehicles are rechargeable, there is a limit to the amount of times they can be recharged before having to be replaced
Batteries are more expensive to make
Batteries store less energy than fuel cells, so they would need recharging more often
How does a hydrogen-oxygen fuel cell work?
The electrolyte is often a solution of potassium hydroxide, and the electrodes are often porous carbon with a catalyst. Hydrogen goes into the anode compartment and oxygen goes into the cathode compartment. At the negative electrode, hydrogen produces H+ ions. The H+ ions in the electrolyte move to the cathode. At the positive electrode, oxygen gains electrons from the cathode and reacts with H+ ions to make water. The electrons flow through an external circuit from the anode to the cathode - this is the electric current.
Give the half equations of what is happening at each electrode during electrolysis of hydrogen and oxygen
Negative electrode: H2 --> 2H+ + 2e-
Positive electrode: O2 +4H+ +4e- --> 2H2O
What is collision theory?
The faster particles collide, and if they have more force, the quicker the reaction takes place, as there are more successful collisions
What four things does the rate of a reaction depend on?
Temperature
Concentration or pressure
Surface area
Presence of a catalyst
Why does a higher temperature increase the rate of a reaction?
The particles move faster and they have more energy, meaning they are likely to collide more often, and with more force, so more of the collisions will have enough energy to make the reaction happen
How does a higher concentration or pressure increase the rate of a reaction?
If a solution is more concentrated, there are more particles in the same volume. This makes collisions happen more frequently, leading to an increased chance of successful collisions
How does an increase in surface area lead to a higher rate of reaction?
If the surface area is larger, this increases the solid's surface are to volume ratio. The other reactant will have a larger area to react with, meaning successful collisions are more likely
How do catalysts speed up the rate of a reaction?
They decrease the activation energy needed to start the reaction by providing an alternative reaction pathway with a lower activation energy
How do you calculate the rate of a reaction?
Amount of reactant used OR amount of produce formed / time
Give the three ways of measuring the rate of a reaction
Precipitation and colour change
Change in mass (usually gas given off)
The volume of gas given off
What is a disadvantage of using precipitation and colour change to measure the rate of a reaction?
People may not agree on the exact point it changes or disappears, and you cannot plot a rate of reaction graph from the results
What is a disadvantage of using change in mass to measure the rate of a reaction?
The gas gets released straight into the room
What is a disadvantage of using the volume of gas given off to measure the rate of a reaction?
If the reaction is too vigorous, it could blow the plunger out of the end of the syringe
How do you find the rate of a reaction at a particular point on a graph?
Draw a tangent and use change in y / change in x
What reactions will reach equilibrium?
Reversible reactions
What affects the position of equilibrium?
Temperature
Pressure
Concentration
What is equilibrium?
As the reactants react, their concentrations fall - so the forward reaction will slow down, however at the same time, the backwards reaction will speed up. At equilibrium, both reactions are still happening, but there's mo overall effect. This means the concentrations of reactants and products won't change
Give an example of a reversible reaction
Hydrated copper sulfate to anhydrous copper sulfate and water
What is a pure substance?
Something that only contains one compound or element
What does the boiling or melting point tell you about how pure a substance is?
The closer your measured value is to the actual melting or boiling point, the purer your substance is. Impurities in your sample will lower the melting point and increase the melting range of your substance. They will also increase the boiling point, and may result in a range of boiling temperatures.
What are formulations?
Useful mixtures with a precise purpose that are made by following a formula. Each component in a formulation is present in a measured quantity, and contributes to the properties of the formulation so that it meets its required function
What are the four components that make up paint, and why are they used?
Pigment - gives the paint colour
Solvent - used to dissolve other components and alter the viscosity
Binder (resin) - forms a film that holds the pigment in place after it has been painted on
Additives - added to further change the physical and chemical properties of the paint
Why are formulations very important in the pharmaceutical industry?
By altering the formulation of a pill, it can be ensured the drug is delivered to the correct part of the body at the right concentration, that it's consumable, and has a long enough shelf life
How do you test for chlorine?
It bleaches damp litmus paper, turning it white
How do you test for oxygen?
If you put a glowing splint inside a test tube containing oxygen, the oxygen will relight it
How do you test for carbon dioxide?
Limewater goes cloudy
How do you test for hydrogen?
You will hear a squeaky pop when a burning splint is held over the open end of a test tube containing hydrogen
What is chromatography?
An analytical method used to separate the substances in a mixture
What is a mobile phase?
Where the molecules can move. It is always a liquid or gas
What is a stationary phase?
Where the molecules can't move. It is a solid or a really thick liquid
Which two things affect the amount of time the molecules spend in each phase?
How soluble they are in the solvent
How attracted they are to the paper
How do you calculate the Rf?
Distance travelled by substance / distance travelled by solvent
How do you test for carbonates?
Use dilute acid and add it to the test tube that contains your mystery substance. Connect this to a test tube containing lime water. If the limewater goes cloudy, carbonates are present
How do you test for sulfates?
Barium chloride and hydrochloric acid. Add a few drops of dilute HCl and then a few drops of barium chloride solution (BaCl2) to a test tube containing your mystery solution. If sulfates are present, a white precipitate of barium sulfate will form.
How do you test for halides?
Nitric acid and silver nitrate
What colour precipitate does a chloride give of silver chloride?
White
What colour precipitate does a bromide give of silver bromide?
Cream
What colour precipitate does an iodide give of silver iodide?
Yellow
What colour does lithium go in a flame test?
Crimson
What colour does sodium go in a flame test?
Yellow
What colour does potassium go in a flame test?
Lilac
What colour does calcium go in a flame test?
Orange-red
What colour does copper go in a flame test?
Green
How do you perform a flame test?
Take a nichrome or platinum wire loop and clean it by rubbing it with fine emery paper, and hold it in a blue flame on a Bunsen burner. Once the flame is blue again, the loop is clean. Dip the wire loop into the sample you are testing and put it back in the flame
What colour precipitate do calcium ions form with sodium hydroxide?
White
What colour precipitate do copper II ions form with sodium hydroxide?
Blue
What colour precipitate do iron II ions form with sodium hydroxide?
Green
What colour precipitate do iron III ions form with sodium hydroxide?
Brown
What colour precipitate do aluminium ion form with sodium hydroxide?
White, then colourless
What colour precipitate do magnesium ions form with sodium hydroxide?
White
Why is FES better than a flame test?
It can identify different ions in mixtures
Give three advantages of instrumental analysis
Very sensitive
Very fast
Very accurate
What happened in phase 1 of the atmosphere evolution?
Lots of volcanoes
Mostly carbon dioxide, like Mars and Venus today
The volcanoes released nitrogen into the atmosphere
What happened in phase 2 of the atmosphere evolution?
Water vapour condensed and formed oceans
Carbon dioxide dissolved and formed carbon precipitates which formed sediment on the sea bed
Marine animals evolved and their shells contained some carbonates
Green plants and algae evolved and carried out photosynthesis
What are fossil fuels?
Coal, oil and natural gas made by decaying organisms being compressed by sediment to form sedimentary rocks, oil, and gas
What are crude oil and natural gas formed from?
Deposits of plankton
What is coal formed from?
Thick plant deposits
What is the current composition of the Earth's atmosphere?
Nitrogen - 78%
Oxygen - 21%
Argon - 0.9%
Carbon dioxide - 0.035%
Other - 0.065%
Give three greenhouse gases
Carbon dioxide, methane, water vapour
What do greenhouse gases do?
Don't absorb incoming short wavelength radiation from the Sun
Do absorb long wavelength radiation reflected off Earth
Re-radiate in all directions
Give four human activities that affect the amount of greenhouse gases in the atmosphere
Deforestation
Burning fossil fuels
Agriculture
Creating waste
Give four possible consequences of climate change
Ice caps melt - floods, erosion and sea levels increase
Rainfall patterns change
Frequency and severity of storms increases
Distribution of organisms changes
What are carbon footprints?
They measure the amount of carbon dioxide and other greenhouse gases released over the life cycle of something e.g. service, event, or product
What are five ways of reducing carbon footprints?
Renewable or nuclear energy instead of fossil fuels
More efficient processes to conserve energy and cut waste
Government tax
Emissions cap
Carbon dioxide changing technology
What are three issues with making reductions to carbon footprints?
Lots of work needed for cheaper technology
Bad economic growth
Most countries won't sacrifice their economic growth if no one else is
How can individuals reduce their carbon footprint?
Cycle or walk
Reduce air travel
Save energy at home
What happens in incomplete combustion?
Solid particulates and carbon dioxide are produced
What are two problems particulates can cause?
Respiratory problems if they are breathed in
Global dimming
What does carbon monoxide do?
Binds to haemoglobin in the blood which reduces the efficiency of delivering the blood around the body
Can lead to fainting, coma, or death
Has no colour or smell so is even more dangerous
Why is sulfur dioxide released?
Sulfur impurities during burning
Why are sulfur dioxide and oxides of nitrogen bad?
Acid rain - kills plants, damages buildings and statues, and corrodes metals
Can cause respiratory problems