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Monitoring the Environment Flashcards

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1
Q

What are three common effects of Global Warming?

A
  • More erratic weather patterns increasing severity of natural phenomena.
  • Patterns of cropping in agriculture.
  • Animal species and their migration patterns.
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2
Q

What happens when ice melts around the world?

A

The sea level rises.

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3
Q

Describe why ice melting increases the overall global temperature

A

Ice and glaciers reflect solar radiation and therefore as these melt, there is an increase in the absorption of solar radiation in the Earth’s surface further increasing average global temperature.

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4
Q

What is Permafrost?

A

Permafrost a combination of soil, rocks and sand all held together by ice.

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5
Q

What are the dangers of permafrost?

A
  • Building are built on top of permafrost meaning when it melts a sink hole could form and the building will collapse.
  • Permafrost contains frozen organic materials which can be toxic to our environment.
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6
Q

What are the earths average temperatures with and without the Greenhouse Effect?

A
  • Without: -17°C
  • With: 15°C
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7
Q

Why do we need the Greenhouse Effect?

A

It is natural and essential for life to be able to survive on earth. Earth absorbs heat energy which maintains a steady atmospheric temperature, supporting life.

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8
Q

Why do we need the greenhouse effect?

A

Without the greenhouse effect, the radiation would be lost to space, leaving earth with minimal warmth.

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9
Q

What are the three types of radiation that enter Earths atmosphere?

A
  • Infrared radiation (IR)
  • Visible light (ROYEBIV)
  • Ultraviolet radiation (UV)
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10
Q

What happens to Solar radiation that is incoming to Earth?

A
  • 30% of the incoming radiation is reflected back into space.
  • 20% is absorbed by the atmosphere.
  • 50% is absorbed by Earth’s surface.
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11
Q

What is the Greenhouse Effect?

A

The Greenhouse Effect is the process of UV and Visible light emitted from the sun passing through the atmosphere heating the Earth. Earth absorbs some of the UV and Visible light and re-emits the rest back to the lower atmosphere as longer wave; Infrared radiation. The IR radiation absorbed by the lower atmosphere is then re-radiated to other molecules in the atmosphere, out to space and back to Earth. This process creates a thermal balance with the amount of thermal radiation entering the atmosphere in equilibrium with the amount of thermal radiation emitted back into space.

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12
Q

Why do Greenhouse gases require polar bonds?

A

Greenhouse gases need polar bonds as polar bonds can stretch or bend asymmetrically, absorbing and re-radiating thermal radiation.

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13
Q

What are common Greenhouse gases?

A

Carbon Dioxide (CO2), Nitrous Oxide (N2O), Water Vapour (H2O) and Methane (CH4).

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14
Q

What is a polar bond?

A

Polar bonds are covalent bonds between atoms with different electronegativities, leading to unequal sharing of valence electrons. This leads to the formation of a positive and negative dipole.

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15
Q

What is the Enhanced Greenhouse Effect?

A

Increased levels of greenhouse gases produced by anthropogenic sources disrupt the thermal balance of the atmosphere as there is more greenhouse gases to absorb the IR radiation. Thus, less thermal radiation escapes Earth’s atmosphere causing an increase in the overall temperature of Earth i.e global warming.

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16
Q

What are anthropogenic sources causing an increase in greenhouse gases?

A
  • Burning of fossil fuels
  • Clearing of rainforests
  • Agricultural activity (ruminant animals farting, transportation of goods, fertiliser use)
  • Landfill
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17
Q

What is ocean acidification?

A

The ocean absorbs excess CO2 from the atmosphere (caused by humans). The release of hydronium ions increase the acidity which can harm marine organisms and ecosystems.

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18
Q

What is photochemical smog?

A

It is a type of air pollution formed during the day over large cities with polluted air.
It is a brown haze formed due to the presence of nitrogen dioxide in the air.

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19
Q

What is volumetric analysis?

A

A quantitative analytical technique used to determine amounts or concentrations of unknown reagents (reactants).

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20
Q

Where is volumetric analysis used?

A
  • Quality control in the food industry.
  • Wine Industry
  • Medical industry
  • Pharmaceutical Industry
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21
Q

What is a limiting reagent?

A

The reagent that is completely consumed within a reaction.

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22
Q

What happens when too much CO2 is absorbed into the ocean?

A

The pH level of the water decreases, harming marine organisms and ecosystems.

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23
Q

What is the equation when CO2 is absorbed into the ocean?

A

CO2 + Water <-> Carbonic Acid
CO2(g) + H2O(l) <-> H2CO3(aq)

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24
Q

What is the ionisation of Carbonic Acid?

A

H2CO3(aq) + H2O(l) <-> HCO3- + H3O+
HCO3-(aq) + H2O(1) <-> CO32- + H3O+

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25
Q

What happens to the pH as more carbon dioxide is released into the water?

A

The release of hydronium ions increases the acidity/decreases the pH of the ocean.

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26
Q

How to calculate pH?

A

pH = -log [H+}

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27
Q

How do you calculate the concentration of H+ or OH- ions?

A

[H+] = 10^-pH
[OH-] = 10^-pOH

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28
Q

What impacts does ocean acidification have?

A

The skeletons and shells of many marine organisms are made of calcium carbonate. This causes the shells to dissolve because the H3O+ ions are an acid. So, acid + carbonate -> salt + water + carbon dioxide.

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29
Q

What is the reaction of calcium carbonate and H+ ions in the ocean?

A

CaCo3(s) + 2H+(aq) -> CO2(g) + H2O(l) + Ca2+(aq)

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30
Q

State the effect that ocean acidification has on marine life and ecosystems.

A

Calcium carbonate is the main building block of sea shells, coral and crabs. These organisms build their shells and skeletons from the calcium ions and carbonate ions in the ocean.

Ca2+(aq) + CO3 2-(aq) -> CaCO3(s)

As the pH of the ocean decrease, the additional protons cause the dissolution of the solid calcium carbonate, weaking the shells and skeletons and also making it harder for them to build shells and skeletons.

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31
Q

Why is nitrogen gas so stable?

A

It has a triple bond that requires high energy to separate.

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32
Q

What are high energy sources that can break the N2 bond?

A

Bush fires
Lightning Strikes
Car engines
Volcanoes
Combustion engine

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33
Q

How is NO2 formed?

A

After a high enough energy has been supplied, nitrogen reacts with atmospheric oxygen to produce nitric oxide.

N2(g) + O2(g) -> 2NO2(g)
HIGH ENERGY ON THE ARROW

This can then undergo further reaction with atmospheric oxygen to form nitrogen dioxide.

2NO(g) + O2(g) <-> 2NO2(g)

34
Q

What is the process of NO2 undergoing a further reaction?

A

NO2 can undergo a photochemical reaction.

NO2(g) -> NO(g) + O’
UV on arrow.

Highly reactive O’ (Oxygen radicals) can then undergo further reactions with atmospheric oxygen gas to produce ozone:

O’ + O2(g) -> O3(g)

Ozone and nitrogen oxides act as pollutions within the atmosphere.

35
Q

What are the conditions required for photochemical smog?

A
  • High concentrations of pollutants (motor transport, industrial area or high population density)
  • Sunlight
  • Still conditions (no wind)
  • Temperature Inversion (cool at surface, hot above)
36
Q

What are the effects of nitrogen dioxide on a person?

A

High levels of NO2 consumption can cause:
- Respiratory tract damage
- Increase in severity of asthma and other respiratory infections
- Lung disease
- Reduction of smell and eye irritation

37
Q

What are the effects of nitrogen dioxide on the environment?

A

High levels of NO2 can lead to decrease of crow growth and yield.

38
Q

What are the effects of Ozone on people?

A
  • Irritation and inflammation of respiratory systems
  • Reduced lung function
  • Increased asthma and respiratory disease effect
  • Decrease in respiratory immunity.
39
Q

What are the effects of ozone on plant life?

A
  • Stomas (tiny pore that open to allow for gas exchange) will close in response to ozone.
  • Prevents photosynthesis and hydration further stunting plant growth.
  • If a plant intakes ozone it will destroy the internal structure.

This all leads to a decrease in crop yield during harvests.

40
Q

What are the effects of ozone on materials?

A

Rubbers and plastics can be damaged by the presence of ozone.

41
Q

What are primary pollutants?

A

Pollutants that are directly emitted into the atmosphere (car exhaust or industry).

42
Q

What are secondary pollutants?

A

Pollutants produced in the atmosphere by chemical reactions.

43
Q

What are examples of primary pollutants?

A
  • Nitrogen oxides (NO, NO2, NO3 etc)
  • Sulfur dioxide SO2
  • Carbon dioxide CO2
  • Carbon monoxide CO
  • Hydrocarbons
44
Q

What are examples of secondary pollutants?

A
  • Ozone O3
  • Aldehydes
  • Sulfuric acid H2SO3
  • Sulfurous acid H2SO4
45
Q

How have we tried to reduce photochemical smog?

A
  • Banning fossil fuels
  • Only using electric cars
  • Incentives for industries to reduce NO2 generating practices

However, these all were contradictory.

46
Q

How do catalytic converters reduce photochemical smog?

A

A catalytic converter uses a chamber called a catalyst to change the harmful compounds from an engine’s emissions into safe gases, like steam. It works to split up the unsafe molecules in the gases that a car produces before they get released into the air.

However, as they have platinum, palladium and rhodium they are extremely expensive and get stolen.

47
Q

What is the chemistry of internal combustion engines? And how does this apply to photochemical smog?

A

Hydrocarbons react with oxygen in a combustion reaction to produce energy.

The heat within a combustion engine is also sufficient enough to form nitrous oxide.
N2(g) + O2(g) -> 2NO(g)

Leading to further formation of nitrogen dioxide and photochemical smog.
2NO + O2(g) -> 2NO2(g)

48
Q

What is chromatography?

A

Chromatography is the purification or identification of chemical compounds by separating the components of a mixture.

49
Q

What are the four types of intramolecular forces?

A
  • Ion dipole
  • Hydrogen bonding
  • Dipole - dipole
  • Dispersion forces
50
Q

What is ion-dipole?

A

It is the strongest type of secondary interaction. This is because of the electrostatic attraction between an ion (either positive and negative) and a polar molecule.

51
Q

What is hydrogen bonding?

A

It is a special type of dipole dipole interactions that occurs between a hydrogen bonded to oxygen, nitrogen or fluorine.

52
Q

What is dipole dipole bonding?

A

An intramolecular force that occurs when the partially positive region of a molecule interacts with the partially negative end of another molecule, hence the molecule must be polar.

53
Q

What are dispersion forces?

A

The weakest intramolecular force that exists between all types of molecules. The more electrons the stronger the dispersion forces are.

It is caused by the movement of electrons causing a temporary dipole. This will only occur for non-polar molecules.

54
Q

What is adsorption?

A

Interactions of the particles on the surface of the material. Use for chromatography.

55
Q

What is the chromatography theory?

A

The components within a mixture are separated based on their differing polarities. The separation in the mixture occurs due to the components adsorption to the stationary phase and the solubility in the mobile phase.

56
Q

What is a stationary phase?

A

Typically a solid material to which mixture components adsorb or adhere too.

56
Q

What is a mobile phase?

A

The liquid or gas which transports components across a stationary phase.

57
Q

How to determine the relative polarity of a molecule?

A

Consider:
The functional groups
The size

57
Q

What are the five types of chromatography?

A
  • Thin layer chromatography (TLC)
  • Gas chromatography (GC)
  • High-performance liquid chromatography (HPLC)
  • Ion chromatography (IC)
  • Column chromatography
58
Q

What is thin layer chromatography TLC

A

It involves a TLC plate normally glass or aluminum or plastic, coated by a layer of adsorbent (typically silica) acting as a stationary phase.
The silica coating is normally polar, but for a reverse phase it is non-polar.

59
Q

How to calculate the Rf factor?

A

distance travelled from origin/distance from origin to solvent front

60
Q

What is the Rf factor?

A

The retention factor (Rf) is used to compare and help identify compounds. The Rf value of a compound is equal to the distance traveled by the compound divided by the distance traveled by the solvent front

61
Q

What is column chromatography?

A

A column that is packed with a solid absorbent (typically silica) that acts as the stationary phase.
The sample mixture is added to the top of the column and the solvent is ran through.
Components have a relative attraction to the solvent and adsorbent, allowing them to separate into bands as they move through the column. This results in each band leaving the column at different times allowing for separation.

62
Q

What is Gas Chromatography?

A

If a component is volatile (evaporates easily) gas chromatography is used.
A long column of a very small diameter is looped into a coil and heated in an oven. The stationary phase consist of a fine coating on the inner surface or is packed into the column as a solid adsorbent
A small sample of the mixture is injected into the heated coil and is vaporized. An inert (unreactive) carrier gas (typically nitrogen) is used as mobile phase to transport the components through the coil.

63
Q

What is High performance liquid chromatography?

A

HPLC is used for mixtures which are harder to separate using column chromatography (very similar compounds) or mixtures that contain very small amounts of analyte.
The solid adsorbent acting as the stationary phase is packed into or coated onto the inside of the column. The stationary phase is often very fine.
The sample mixture is injected into the column and is transported by the liquid mobile phase (eluent) which is pumped under pressure making the column efficient.
A detector is used to record the retention times and relative amounts of each component as recorded by a chromatogram.

64
Q

What is retention time?

A

A measure of the time taken for a solute to pass through a chromatography column

65
Q

What is atomic absorption?

A

Atomic absorption is a special application in which ground-state atoms of metals absorb light at very specific wavelengths corresponding to the energy needed to cause electronic transitions in their electron orbitals.

66
Q

What is a ground state is Atomic Absorption?

A

It is when electrons occupy the lowest energy level possible. This is the ground state.

67
Q

What is the excited state in atomic absorption?

A

Electrons within the atom can absorb photons of discrete amount of energy in the form of heat, light or electricity which promotes electrons to a higher energy level, the excited state of an atomic.

68
Q

How are electrons promoted into a higher energy level?

A

Atoms can only absorb photons of a discrete amount of energy corresponding to the energy required to promote an electron from the ground state into a higher energy level.

This specific amount of energy absorbed is unique to each element but there is overlap between species.

69
Q

When is light emitted from an atom?

A

An excited state atom is unstable and therefore readily returns to its ground state via the loss of additional energy.

Typically this energy is emitted as a photon (light) resulting in atomic emission.

70
Q

What is the emission spectrum?

A

The light emitted by a species once relaxation occurs from an excited to a ground state. This results in bright coloured lines on a dark background.

71
Q

What is absorption spectrum?

A

It corresponds to the light absorbed to excite an atom from its ground state to an excited state. It produces dark lines on a coloured background.

72
Q

What is the responsibility of a hollow cathode lamp?

A

The hollow cathode lamp needs to be the same as the metal being investigated. This provides the radiation through stimulated atomic emission.

The electrons of the metal we wish to analyse are excited to emit radiation at their characteristic frequency.

The characteristic radiation of the metal atom is directed toward the flame by an optical device.

An incident reading is recorded (a spectrum without any sample present).

73
Q

What is the role of the flame and mixing chamber in AAS?

A

The sample under analysis is sprayed into the flame decomposing the metallic compounds into metal atoms and ions.

The energies of the radiation from the lamp that match the energy transitions of the metal atom in the flame are absorbed.

74
Q

What is the role of the monochromator in AAS?

A

The absorbed energy is them re-radiated by the atoms in the flame in all directions, with little rejoining the incident beam.

Unabsorbed radiation is then transmitted through a monochromator to select one of the frequencies.

The selected radiation is sent to a detector which measures the absorbance value by measure the difference between incident and transmitted radiation.

75
Q

How to construct a calibration curve?

A

Standard solutions of increasing known concentration are prepared for the metal under investigation.

A blank of distilled water is prepared and introduced along with the known standards to the AAS apparatus and the absorbance value obtained for each.

A graph is then plotted of absorbance against concertation and a line or curve of best fit applied.

The absorbance from the unknown sample/s can then be plotted the concentration interpolated.

76
Q

What are the three catalytic converter equations?

A

Carbon monoxide into carbon dioxide
2CO(g) + O2(g) -> 2CO2(g)

Nitrogen Oxides into Nitrogen gas
2CO(g) + 2NO(g) -> N2(g) + 4H2O(l)

Unburnt hydrocarbons from incomplete combustion
C3H8(g) + 5O2(g) -> 3CO2(g) + 4H2O(l)

77
Q

How are greenhouse gases produced?

A

CH4 - landfill and agriculture
CO2 - Burning of fossil fuels and clearing of rainforests
N2O - internal combustion engines and fertilisers

78
Q

What is the photosynethsis equation?

A

6CO2 + 6H2O → C6H12O6 + 6O2.

79
Q
A
79
Q
A

Chemistry (4 decks)

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