Stage 2 Chemistry, Unit 1.1- Monitoring the Environment- Global warming and ocean acidification

What are some commons greenhouse gases?

CH₄, CO₂ H₂O, O₃, NO_x

What is the Greenhouse effect?

The Greenhouse Effect – a natural process that allows the Earth to trap energy from the Sun through the use of ‘greenhouse gases’ which block a longer wave length of light from being re-emitted into space.

How does the greenhouse effect work?

The Sun emits ultra violet (UV), visible and infra-red (IR) radiation (light). As this light reaches Earth a number of things happen:

30% of the radiation is reflected back to space due to albedo (reflectivity of ice, snow, clouds and water)

22% is absorbed by the gases present in stratosphere

48% is absorbed by the Earth’s surface, and then re-emitted back out to space.

17% of this 48% is then re-radiated as IR radiation (lower in energy, longer wavelengths).

12% of this 17% ‘s thermal re-radiation passes through the atmosphere, back into space

However, the last 5% of the 17% is absorbed by greenhouse gases, which then re-radiates the thermal radiation to other molecules, to space and to the atmosphere

What does the greenhouse effect keep the world temperature at? (meann)

15c

How warm would the world be without the greenhouse effect?(mean)

-17c

What does Albedo mean?

The reflectivity of the world, due to ice, snow, clouds and water.

Structural formula of Water(H₂O)

bend(v shape)

Structual formula of Carbon Dioxide

is linear

Structural formula of Methane

tetrahedral

Structural formula of Nitrous oxide

linear (a triple bond and a single bond)

Structural formula of ozone

bent/ v shape (due to electron pair

All greenhouse gases

occur naturally, but have had increased concentration due to anthropogenic influence

What is thermal balance?

the amount of energy entering the atmosphere is equals to the amount emitted

The earth-atmosphere energy balance is achieved as the energy received from the Sun balances the energy lost by the Earth back into space.

What is the enchanced greenhouse effect

Global warming (enhanced greenhouse effect) is the gradual increase in the Earth’s surface temperature over time, caused by an increase in the concentration of greenhouse gases in the atmosphere. The enchanced greenhouse effect is influenced by Anthropogenic activ

What is bad about the enhanced greenhouse effect?

An increase in greenhouse gases results in more IR radiation being absorbed and released around earth, overall increasing the temperature from its maintained temperature.

How much more TW of heat are being absorbed due to the enhanced greenhouse effect?

380TW

What are some examples of anthropogenic influences that have led to global warming?

burning of fossil fuels,

industrialisation (the need for cars and the combustion of their engines)

deforestation

farming of ruminant animals

What are some impacts of the enhanced greenhouse effect?

Global temperature rise

Declining artic sea ice, shrinking ice sheets and retreating glaciers

Rising sea levels

Climate and extreme weather events

Ocean Warming

Carbon dioxide is a

non metal oxide

non metal oxides are

acidic oxides (they react with water to make an acid)

What is the formula for pH?

pH = -log [H₃O⁺]

What is the formula for hydronium concentration?

[H₃O⁺] = 10^-pH

What is the formula for hydronium concentration when only hydroxide concentration is known?

1×10^(-14)/OH=[H_3 O]

Ocean acidifacation is a result of

Carbon Dioxide being absorbed by water

Carbon dioxide dissolves in water to form

Carbonic acid ( CO₂+H₂O→ H₂CO₃₎)

Carbonic acid is a

weak acid, meaning it partially ionises to make an equilibrium ( it is a reversible reaction)

What type of polyprotic acid is carbonic acid?

A diprotic acid

Carbonic acid partially ionises to make

Hydronium ions and carbonate ions

H₂CO_3(aq) + H₂O_(l) ⇄ H₃O⁺_(aq) + HCO₃^-_(aq)

uHydrogen carbonate ions further ionise to form

carbonate ions and hydronium ions

HCO₃^-_(aq) + H₂O_(l) ⇄ H₃O⁺_(aq) + CO₃^2-_(aq)

how does the ionisation of Carbonic acid to hydrogen carbonate effect the ocean?

it lowers the pH

How does the addition of more carbon dioxide from global warming disrupt the equilibrium of Carbonic acid?

As more CO₂ molecules are introduced to the ocean, they eventually fully ionize to increase the hydronium concentration of the ocean. Due to le chatlier’s principle, when one side of an equilibrium is increased, another must also increase, this leads to more creation of Hydrogen carbonate ions in the ocean.

What are the effects of ocean acidifacation?

The increase in hydronium ions in the ocean due to CO₂ absorption also leads to the creation of more Hydrogen carbonate ions,which decreases the amount of carbonate ions present, which are used for coral and other marine organisims to grow. The increased amount of protons/ hydrogen ions/ hydronium also attacks marine organisims to achieve this, breaking their calcium carbonate into individual ions.

what is the formula for the degradation of coral through the addition of a lower pH?

CaCO_3(aq) + 2H⁺_(aq)—>CO_2(g)  + H₂O_(l) + Ca²⁺_(aq)

this reaction creates more CO₂ in the atmosphere which further effects ocean acidifacation.

As pH decreases in the ocean, so does the

concentration of carbonate ions decreases. this effects the ocean as marine organisms need carbonate to build their shells