C1 - Air Quality Flashcards
What is the thin layer of gases called that surrounds the Earth?
The atmosphere
How much nitrogen does the atmosphere contain?
78%
How much oxygen does the atmosphere contain?
21%
How much argon (and other noble gases) does the atmosphere contain?
1%
How much of water vapour, carbon dioxide, and other gases does the atmosphere contain?
Small amounts
State the composition of the atmosphere.
78% nitrogen
21% oxygen
1% argon and other noble gases
Small amounts of water vapour, carbon dioxide and other gases
Describe the 4 stages by which scientists believe that the atmosphere probably evolved.
- The early atmosphere was created by volcanic activity and consisted mainly of carbon dioxide and water vapour.
- As the Earth cooled, the water vapour condensed to form the oceans.
- Simple photosynthetic organisms evolved in the oceans, adding oxygen to the atmosphere and removing carbon dioxide.
- Some carbon dioxide was removed due to it dissolving in the oceans and forming sedimentary rocks and fossil fuels.
How do scientists believe the early atmosphere was created?
By volcanic activity
What do scientists believe that the early atmosphere consisted of?
Mainly of carbon dioxide and water vapour
What do scientists believe happened to the Earth so that water vapour condensed into the oceans?
The Earth cooled.
How do scientists believe the oceans were created?
As the Earth cooled, water vapour found in the early atmopshere condensed to form the oceans
What role do scientists believe the ocean had during the early stages of the Earth in the atmosphere?
As simple photosynthetic organisms evolved in the oceans, oxygen was added to the atmosphere and carbon dioxide was removed from the atmosphere.
What do scientists believe happened within the oceans that meant oxygen was added to the atmosphere and carbon dioxide was removed from the atmosphere in the early stages of the earth?
Simple photosynthetic organisms evolved in the oceans
How do scientists believe carbon dioxide was removed from the atmosphere in the early stages of the earth? (2 ways)
- Simple photosynthetic organisms evolved in the oceans, removing carbon dioxide from the atmosphere (and adding oxygen to it)
- Some carbon dioxide was removed due to it dissolving in the oceans and forming sedimentary rocks and fossil fuels
Why are pollutants chemicals?
They can harm the environment and our health
Give an example of a human action that releases pollutants into the atmosphere.
Burning fossil fuels
How do power stations and cars release pollutants into the atmosphere?
Burning fossil fuels
True or False?
Pollutants cannot harm us indirectly.
False - Pollutants can harm us indirectly.
Give an example of how pollutants can harm us indirectly and the effect they have.
Acid rain makes rivers to acidic for organisms to survive - this affects some food chains and natural resources (like trees)
Name some pollutants.
- Carbon dioxide
- Nitrogen oxides
- Sulfur dioxide
- Particulates (small particulates of solids, e.g. carbon)
- Carbon monoxide
What can carbon dioxide be harmful to?
The environment
What can nitrogen oxides be harmful to?
The environment and humans
What can sulfur dioxide be harmful to?
The environment
What can particulates be harmful to?
The environment and humans
What can carbon monoxide be harmful to?
Humans
Explain how carbon dioxide can be harmful to the environment.
It traps heat in the Earth’s atmosphere as it’s a greenhouse gas
Explain how nitrogen oxides can be harmful to the environment.
It can cause acid rain
Explain how nitrogen oxides can be harmful to humans.
it can cause breathing problems and make asthma worse
Explain how sulfur dioxide can be harmful to the environment.
It can cause acid rain
Explain how particulates can be harmful to the environment.
It makes buildings dirty
Explain how particulates can be harmful to humans.
It can make asthma and lung infections worse if inhaled
Explain how carbon monoxide can be harmful to humans.
It prevents the blood from carrying oxygen which can be fatal
How can concentrations of pollutants in the air be measured?
In ppb (parts per billion) or ppm (parts per million)
What can ppb be used to measure?
Concentrations of pollutants in the air
What can ppm be used to measure?
Concentrations of pollutants in the air
Other than ppb, what can be used to measure concentrations of pollutants in the air?
ppm (parts per million)
Other than ppm, what can be used to measure concentrations of pollutants in the air?
ppb (parts per billion)
What does ppb stand for?
parts per billion
What does ppm stand for?
parts per million
A sulfur dioxide concentration has a concentration of 16ppb. Explain what exactly this means and how many molecules will be sulfur dioxide.
In every 1 billion molecules of air, 16 molecules will be sulfur dioxide
What is it important to do when measuring the concentrations of pollutants?
Repeat the measurements
Give an example as to why it is important to repeat the measurements when calculating the concentrations of pollutants.
Because the concentration could change - the concentration of nitrogen oxides from cars could change depending on the time of day, the amount of traffic, or the weather.
Why is it important to repeat the measurements when calculating the concentrations of pollutants?
Repeat measurements will allow a chemist to calculate a mean, which will give a good estimate of the true value of the concentration of the pollutant.
What is considered to be the ‘building blocks’ of all materials?
Elements
What are elements considered to be?
The ‘building blocks’ of all materials
Elements are the ________ ____________ of all materials.
Building blocks
Elements are the ________ ____________ of ___ materials.
Building blocks; all
Roughly how many elements are there? Is it…
a) Between 10 and 50
b) Between 50 and 100
c) Over 100
The answer is c) over 100.
What are elements made of?
Tiny particles called atoms.
All atoms of a particular element are ___ ____ and ______ to that elemtn.
the same; unique
What can atoms join together to form?
Bigger building blocks called molecules
What are molecules made out of?
Atoms
When do compounds form?
When the atoms of two or more different elements chemically combine.
True or False?
The properties of compounds are very similar from the properties of the elements they’re made from.
False - The properties of compounds are very different from the properties of the elements they’re made from.
What 2 things are used to write formulae?
- Chemical symbols
- Numbers
What are chemical symbols used in conjunction with to write formulae?
Numbers
What are numbers used in conjunction with to write formulae?
chemical symbols
What can chemical symbols and numbers be used to write?
Formulae
What does a formula show? (2 things)
- Different elements that make up a compound
- Number of atoms of each element in one molecule
What do chemical reactions form?
New substances from old ones
What in the reactants of a chemical reaction is rearranged to make the products of the reaction?
The atoms
Explain in what ways atoms can be used in chemical reactions.
Atoms in the reactants are rearranged to make products:
- Joined atoms may be separated
- Separate atoms may be joined
- Joined atoms may be separated and then joined again in different ways
Atoms in the reactants are rearranged to make products:
- Joined atoms may be separated
- Separate atoms may be joined
- Joined atoms may be separated and then joined again in different ways
How easily are these changes reversible?
Not easily
What can be used to show what happens in a chemical reaction?
Word equations
How are word equations used to show what happens during a chemical reaction?
The reactants are on one side and the products (newly formed chemicals) are on the other side:
reactants —> products
True or False?
No atoms are lost or produced during a chemical reaction, so there will always be the same number of atoms on each side.
True
True or False?
There is the possibility that atoms can be lost or produced during a chemical reaction, so there will always be a different number of atoms on each side.
False - No atoms are lost or produced during a chemical reaction, so there will always be the same number of atoms on each side.
Is mass conserved or wasted during chemical reactions? (HT)
Conserved
Why will there always be the same number of atoms on each side of a chemical reaction?
Because no atoms are lost or produced during a chemical reaction
What happens as a result of the fact that no atoms are created or destroyed in a chemical reaction? (HT)
The total mass of the products is the same as the total mass of the reactants.
No atoms are created or destroyed in a chemical reaction. What does this mean about the mass of products and reactants in a chemical reaction? (HT)
The total mass of the products is the same as the total mass of the reactants.
What is combustion?
Burning; a chemical reaction
When does combustion (burning) occur?
When a fuel reacts with oxygen and energy is released.
Fuel reacts with oxygen within combustion. What sort of reaction, therefore, is combustion?
Type of oxidation reaction
How do we know that combustion is a type of oxidation reaction?
Fuel reacts with oxygen
In an oxidation reaction like combustion, where does the oxygen come from?
The air
Does fuel burn faster with oxygen from the air or with pure oxygen?
Pure oxygen
What is coal mainly made up of?
Carbon
Give the word equation showing what happens when coal is burned.
carbon + oxygen = carbon dioxide
One atom of carbon (solid) and one molecule of oxygen (gas) produces one molecule of carbon dioxide (gas)
When does complete combustion occur?
When there’s enough oxygen present for a fuel to burn completely.
Petrol, diesel and fuel oil consist mainly of compounds called what?
Hydrocarbons
Give the name of 3 substances that consist mostly of hydrocarbons.
- Petrol
- Diesel
- Fuel oil
Give an example of a hydrocarbon compound.
Methane
What do hydrocarbon compounds contain?
Only hydrogen and carbon atoms
What 2 types of atoms can hydrocarbon compounds only contain?
Hydrogen and carbon
What do hydrocarbon compounds produce when burned in air?
Carbon dioxide and water - hydrogen oxide
a) Complete the following equation:
methane + _________ = __________ ________ + water
b) Give the symbol equation.
When does incomplete combustion occur?
When fuel is burned and there’s not enough oxygen.
Depending on the amount of oxygen present, what can be produced in an incomplete combustion reaction?
Carbon particulates or carbon monoxide
a) Where might incomplete combustion occur?
b) Why is this?
a) Car engines
b) Exhaust emissions contain carbon particulates and carbon monodies as well as carbon dioxide.
Coal contains sulfur.
a) Therefore, what is released when it is burned?
b) Give the word equation.
c) Give the symbol equation.
a) During the combustion of fuels, high temperatures (e.g. in car engines) can cause what two things to react to create nitrogen monoxide? (HT)
b) Give the symbol equation. (HT)
a) When nitrogen monoxide is created (during combustion of fuels through reaction of nitrogen and oxygen), what happens next? (HT)
b) Give the word equation for this.
c) Give the symbol equation for this.
When NO and NO[2] occur together, what are they called? (HT)
NO[x]
Give examples of some natural processes that can remove carbon dioxide from the air.
- Photosynthesis in plants
- Dissolves in rain and seawater (where it reacts with chemicals)
Why do carbon dioxide levels increase each year?
We produce so much carbon dioxide that not all of it can be removed from the atmosphere through natural processes, hence the carbon dioxide levels increase each year.
Why is carbon dioxide called a greenhouse gas?
Because it is contributing to global warming, which is leading to climate change?
What is global warming leading to?
Climate change
Carbon dioxide contributes to global warming, which is leading to climate change. Because of this, what is carbon dioxide known as?
A greenhouse gas
What two things react with water to produce acid rain?
Sulfur dioxide and nitrogen dioxide
What does sulfur dioxide and nitrogen dioxide react with to produce acid rain?
Water
What components react to make acid rain?
Sulfur dioxide and nitrogen dioxide, and water
What does a reaction between sulfur dioxide, nitrogen dioxide and water create?
Acid rain
What is the environmental problem with acid rain? (3 things)
- Damages trees
- Corrodes metal
- Upsets pH balance of rivers (causing plants and animals to die)
Acid rain upsets the pH balance of rivers. What environmental issue does this cause?
Causes plants and animals to die.
How can power station emissions be reduced? (3 things)
- Using less electricity
- Removing sulfur and toxic chemicals from gas, coal, and oil before burning
- Using alternative renewable sources (e.g. solar, wind and hydroelectric energy)
How can power station emissions be reduced? (4 things) (HT)
- Using less electricity
- Removing sulfur and toxic chemicals from gas, coal, and oil before burning
- Using alternative renewable sources (e.g. solar, wind and hydroelectric energy)
- Removing sulfur dioxide from flue (chimney) gases by wet scrubbing with either a spray of calcium oxide and water or using seawater (HT)
How are about half of the UK’s carbon monoxide emissions produced?
By road transport
How much of the UK’s carbon monoxide emissions are produced by road transport?
About half
How can car emissions be reduced? (4 things)
- Using low sulfur fuel in a car with a modern fuel efficient engine
- Legal limits for exhaust emissions, enforced by MOT (Ministry of Transport) tests
- Using public transport
- Making sure cars have catalytic converters, which reduce carbon monoxide in the engine exhaust gases
How can the MOT help to reduce car emissions?
It can enforce legal limits for exhaust emissions through car tests
What does MOT stand for?
Ministry of Transport
How can making sure cars have catalytic converters help to reduce car emissions?
It reduces carbon monoxide in the engine exhaust gases
Give 2 examples of reactions that occur in a catalytic converter, including both the word and symbol equations.
What, fundamentally, is the only thing that can reduce emissions?
Burn fewer fossil fuels
a) What, fundamentally, is the only thing that can reduce emissions?
b) Why is this hard?
a) Burn fewer fossil fuels
b) because the population of the world is increasing annually and the demand for energy increases all the time
What can be an alternative energy source (not fossil fuels) for cars? What is the issue with these things? (HT) (2 things)
- Electricity = must be produced renewably
- Biofuels = use up valuable farmland
Describe how the burning of a fuel in a power station leads to acid rain.
Sulfur impurities in fuel react with oxygen. Sulfur dioxide reacts with rainwater.
Nitrogen oxides can also contribute to producing acid rain. Describe how a car engine produces nitrogen oxides.
High temperature causes atmospheric nitrogen to react with oxygen.
