Chemistry Of The Environment

What are the main gases in clean, dry air and their percentages?

Nitrogen (78%), Oxygen (21%), Argon (0.9%), Carbon dioxide (0.04%).

What are the pollutants produced by burning fossil fuels?

Carbon monoxide (CO), sulfur dioxide (SO₂), nitrogen oxides (NOₓ), and particulates.

How is carbon monoxide produced?

By incomplete combustion of organic fuels.

Why is carbon monoxide dangerous?

Causes respiratory issues.

How is sulfur dioxide produced?

By burning fossil fuels containing sulfur impurities.

What environmental problem does sulfur dioxide cause?

Acid rain.

How are nitrogen oxides (NO and NO₂) produced?

In car engines at high temperatures, where nitrogen and oxygen from air react.

What environmental problems do nitrogen oxides cause?

Acid rain and respiratory problems.

What is the effect of acid rain on the environment?

It damages buildings (especially limestone), kills aquatic life, and harms plant growth.

How can acid rain be reduced?

By removing sulfur from fuels and fitting catalytic converters to cars.

What is the composition of natural gas?

Mainly methane (CH₄).

What is the greenhouse effect?

The warming of the Earth’s atmosphere caused by greenhouse gases trapping infrared radiation.

Which gases contribute to the greenhouse effect?

Carbon dioxide (CO₂), methane (CH₄), and water vapour (H₂O).

How does carbon dioxide contribute to global warming?

It traps infrared radiation in the atmosphere.

How is methane released into the atmosphere?

From rice fields, cattle digestion, and decomposition of organic waste in landfills.

What are two main ways to reduce carbon dioxide emissions?

Reducing fossil fuel use and increasing reforestation.

What are the effects of global warming?

Rising sea levels, more extreme weather, and disruption of ecosystems.

What is the main source of particulate pollution?

Incomplete combustion of fuels, especially diesel engines.

What is the effect of particulate pollution on health?

It can cause respiratory illnesses and heart disease.

How can sulfur dioxide be removed from waste gases?

By reacting it with calcium oxide (CaO) or calcium carbonate (CaCO₃) in flue gas desulfurization.

What is the reaction of calcium oxide with sulfur dioxide?

CaO + SO₂ → CaSO₃ (calcium sulfite).

What reaction happens in a catalytic converter?

Carbon monoxide (CO) reacts with nitrogen monoxide (NO) to form carbon dioxide (CO₂) and nitrogen gas (N₂).

How is Carbon Dioxide formed?

Carbon dioxide (CO₂) is formed by complete combustion of organic fuels.

How can Water be harmful?

Eutrophication: Where Nitrates and Phosphates deoxygenate water that endangers aquatic life.

How is water purified?

• Filtration to remove solids

• Carbon added to remove bad taste and odor

• Chlorination to kill bacteria.

List uses for Chlorine, Argon, Ethene and Oxygen.

Chlorine: Kills Bacteria
Argon: Light Bulbs
Ethene: Polyethene
Oxygen: Welding

Describe How Oxygen is Obtained from Air.

Liquify it and then heat, will be successfully obtained to its boiling point.

Explain how Nitrogen Monoxide is formed in an engine.

Nitrogen reacts with Oxygen to form Nitrogen Monoxide, as engine is a high temperature environment.

State another way to test if water is present in a solution without using Anhydrous Copper Sulphate (CuSO4) (II)

Cobalt Chloride Paper.
Color Change: If water is present: Blue Cobalt Chloride turns pink.

How to test if a substance is pure?

It will have fixed melting and boiling points.

State two Industrial Uses of Water.

• Used as a coolant in power stations and factories.

  • Used as a raw material in chemical reactions. (EG: In manufacture of Sulphuric Acid.)