Th pH scale

What should be written in the three boxes?

Complete these sentences:

1. Acid rain is…2. The causes of acid rain are…3. The problems with acid rain are…

Extension:

4. How can we prevent acid rain?

Starter – 5 mins

Acid deposition

Learning outcomesAll of you will be able to:• Identify the components of acid precipitation

Most of you should be able to:• Outline the chemistry leading to the formation

of acidified precipitations• Describe 3 possible effects on soil, water and

living organisms

Acid Deposition

Acid Precipitation

Causes

Acid deposition forms when we burn fossil fuels.

They release:-carbon dioxide-sulphur dioxide-nitrogen oxides

Acid Deposition

These gases are released from

factories, cars and other vehicles.

• The main cause is power stations (which can be used for making electricity), factories and our own homes.

• The burning of coals and oil can release sulphur dioxide and nitrogen oxides as gas. Around half of the nitrogen oxide is from cars

• These gases react with water vapour in the air, making the rain more acidic

• The rain which falls is a weak acid

Acid Deposition

Nitrogen oxides and

sulphur dioxide

cause acid deposition

• Sulphur dioxide (SO2) and water (H2O) form sulphurous acid (H2SO3) and sulphuric acid (H2SO4)

• Some oxides of nitrogen like nitrogen dioxide (NO2) react with water to form nitrous acid (HNO2) and nitric acid (HNO3)

• Carbon dioxide in the air can dissolve in rain water to form carbonic acid, (H2CO3).

Acid DepositionEffects• Direct – weakening tree growth

• Toxic effects – effect of aluminium ions on fish and plant roots

• Nutrient effects – leaching of nutrients

Acid Deposition Acid rain can kill leaves and even the roots, killing the plant

Leaves and buds show yellowing

(loss of chlorophyll),

lesions, thinning of wax cuticle.

Nutrients are leached from the soil,

pathogens and insects gain entry to the trees.

Acid DepositionAcid rain can fall into rivers and lakes causing

plants and animals to die

Acid precipitation

decreases the pH of the soil

making aluminium ions more soluble – this aluminium eventually ends up in rivers and

lakes

Low concentrations – aluminium disturbs the fish’s ability to regulate the amount of salt and

water in its body.

Higher concentrations – aluminium forms a solid in the fish’s gills leading to suffocation

The limestone reacts with the acid and dissolves.

• Acid deposition can cause limestone and marble to deteriorate (become damaged)

• It can also cause damage to the paint on cars if it rains on them for a long time

• It causes plants to become damaged and even die, by landing on the leaves as well as affecting the soil

• It can affect human health if the water is consumed, or in contact with the skin a lot

Explain the process of acid rain using the storyboard in your own words.

You must describe how acid rain ismade and the effects it has on theenvironment.

StoryBoard – 10 mins

StoryBoard – 10 mins

Sulphur dioxide

Nitrogen oxides

pH 7

<pH 5

O2

CaCO3 + H2SO4 - - > CaSO4 + H2CO3

Clues1.Electricity is made in power stations by steam

turning a turbine.

2.When fuels burn they release gases.

3.H2SO4 is the chemical formula for Sulphuric Acid.

4.HNO3 is the chemical formula for Nitric Acid.

5.CaCO3 is the chemical formula for limestone.

Complete these sentences:

1. Acid rain is…2. The causes of acid rain are…3. The problems with acid rain are…

Extension:

4. How can prevent acid rain?

Plenary – 5 mins