FORM SIX: CHEMISTRY STUDY NOTES-TOPIC 10: ENVIRONMENTAL CHEMISTRY

TOPIC 10: ENVIRONMENTAL CHEMISTRY

 ENVIRONMENT CONSERVATION 

Is the protection of natural resources for the future use.

SIGNIFICANCES OF ENVIRONMENTAL CONSERVATION

– To avoid soil erosion.

– To ensure sufficient of water.

– To Adequate supply of resources.

– Reduce Ozone layer depletion.

PROTECTION AND UTILIZATION OF NATURAL RESOURCES
a) Protection of mineral (s) are against over exploitation.

Over exploitation: is the overuse of natural resources.

This cause scarcity of natural resources and environmental destruction.

Protection: – use of scrap metal is instead of extracting minerals from the ground, Recycling.

– Establishing other economic activities instead of mining industries.

– Reducing population pressure through establishment of family planning birth control. This reduces dependency in mining industries for exploiting use.

 Note :-   Utilization: Is the use of natural resources.

 

ENVIRONMENTAL DESTRUCTION

Environmental destruction means destroying the environment which make it not friendly to human survival.

Environmental destruction are die the following reasons.

1. i) Agricultural chemicals .
2. ii) Damping of solid and liquid waste on the land and into large water masses , engravers, wells and oceans.

iii) Opening up gaseous effluent from industries into the air.

AGRICULTURE CHEMICALS
– Use of the pesticides and fertilizer.

– This causes a loss in biodiversity and soil destruction .

– Pesticides causes water pollution , facilitate growth of sea weeds causing oxygen deficiency for marine organism.

– Pollination decline, pesticides kills organisms which are agent of pollination.

EFFECT IN ORGANIC FERTILIZERS
– Soil Acidification.

– Energy consumption.

– Climate Change.

Suggestions

– Use of organic biodegradable.

– Manure.

– Avoid monoculture practices.

1. ii) DAMPING OF SOLID AND LIQUID INDUSTRIAL WASTE OF THE LAND AND INTO LARGE WATER

– Damping of solid and liquid industrial wastes on land and into large water cause deterioration of water quality and land in general.

Petroleum product, heavy metals from the industries may leads to environmental destruction.

• Destruction of environment from petroleum product is mainly due to accidental spills from the ships , tanker trucks , pipe lines and leaky of underground storage tanks.
• Heavy metals such as mercury often deposited with sediment in the bottoms of stream . They may become incorporated into plants.

iii) OPENING UP GASEOUS EFFICIENT FROM INDUSTRIES INTO THE AIR

– Working on the thermal plants and different plants that are used to manufacture different types of fertilizers or pesticides, ,also production of building materials can encourage of the production toxic materials which goes into air in form of smoke.

– Poisonous gases eg. Sulphur dioxide may be emitted also inform of smoke. These cause destruction of air, causing harmfully diseases to human beings.

ENVIRONMENTAL MANAGEMENT INTERVENTIONS

Environment management and interventions should be done through the following: –

1.     i) Management waste.
2.    ii) Chemical treatment of urban sewage.

iii) Chemical treatment of urban supplies of edible / portable water.

POLLUTION

Environmental pollution is the contamination of air, water, and land form man made wastes. Pollution leads to depletion of ozone layer global warming and climate change.

1. WATER POLLUTION (AQUATIC POLLUTION)
   Water pollution is the contamination of water by foreign matter that deteriorates the quality of water. It occurs in lakes, oceans and rivers.

– It involves the release of toxic substances, pathogens, substances that require much oxygen to decompose ,easy – soluble substances and radioactive substances.

1. i) Sources of water pollution

The major forms and the sources of water pollution are: –

1. a) Oil (Petroleum Product) discharged

– These including manufacture of plastics, lubricants solvents and synthetic fabrics fractional distillation of clued oil to produce vehicle fuel , paraffin wax , refinery gases for domestic cooking and bitumen for road surfacing and products is mainly due to accidental spills from the ships , tanker truckers , pipeline and leakage , from underground storage tanks.

1. b) Synthetic chemical pesticides
   – Pesticides such as herbicides, Fungicides used in agriculture and public health programmers to control pests are important source of water pollution.

– They get into water sources through run – off and atmospheric transport and deposition.

– Pesticides accumulates in plants and animals, when they die, they spread to water sources, thus increasing water toxicity.

1. c) Heavy metals

Heavy metals such as mercury are dangerous pollutants. They are often deposited with sediment in the bottom of the streams. When deposited on surface they become incorporated in plants food crops and animals. If they dissolve and water is withdrawn for agriculture or human being use, poisoning can result.

1. i) Management of water

Water management refers to practices of planning developing, distribution and optimum, utilizing of water resources under defined water polices and regulations.
These are: –

1.   a) Management of water treatment of drinking water, industrial water ,sewage or waste water .
2. b) Management of water resources.
3. c) Management of irrigation.

 

Treatment of water maybe divided into two;-

1. i) Purification of domestic use.
2.   ii) Treatment for specialized industrial application.
3. AIR POLLUTION

Air pollution includes all contaminants found in the atmosphere. These are dangerous substances can be either in the form of gases or particles.

Sources of air pollution are natural and human – based.

CAUSES OF AIR POLLUTION

The biggest causes are the operation of fossil fuel , burning power plants, and automobiles that combust fuel.

TYPES OF AIR POLLUTION

1. i) Smog – This is the first type of air pollution.

When smoke present in the atmosphere combine fog present in the air. A mixture formed is Smog or photochemical smog.

1. ii) Green House effect –   It is formed due to the contamination of several important gases with the air. These gases are called green house gases.
2. Methane, sulphur, nitrogen, Carbon monoxide, hydrogen and ozone. These are very harmful for the human skin and causes cancer.

Effects of air pollution

Air pollution affects human health, vegetation and livestock.

1. i) Effects on human health

Severe air pollution cause many fatal diseases and disorders some of the effects caused by inhaling polluted air are: –

1. a) Sulphur dioxide enters soft tissues causing drying of the mouth, scratchy throat and smarting eyes.
2. b) Hydrocarbons and many other air pollutants cause skin cancers.
3. c) Oxides carbon , sulphur , nitrogen diffuse into the blood and combine with haemoglobin causing reduction in it is oxygen carrying capacity.
4. ii) Effects on vegetation

         Air pollution has serious harmful effects on vegetation.

Effects of air pollution on vegetation are :-

1. a) Sulphur dioxide causes chlorosis i.e. loss of effects on tress , plants and vegetation.
2. b) Oxides of nitrogen and fluorides reduces crop yields.
3. c) Photochemical Smog bleaches and blazes foliage of economically important of plants and crops.

iii) Effects on Livestock

General effects of air pollution on livestock are the same as in the case of human being.

Various fluorine compounds which fall on foliage plants are eaten by livestock causing abnormal calcification of bones and teeth, called fluoride toxicity. Fluorosis can causes loss of weight and frequent diarrhea in animals.

3. LAND POLLUTION

This is contamination of land surface through damping , urban wastes , industrial wastes , mineral exploitation and misusing the soil by harmful ,agriculture process.

         Causes 0f land pollution

• Increase in urbanization is major cause of land pollution.
• Construction uses up forest. This leads to the exploitation and destruction of forests.

• Disposal of non – biodegradable wastes included containers, bottles and cans made of plastics, used cars and electronics goods used to the pollution of land.

 

EFFECTS OF LANDS POLLUTION

• Makes places look dirty due of tonnes and tonnes domestic wastes dumped without proper disposal of them.
• Land pollution affects respiratory system of human being.
• Land pollution has serious effects on wildlife. Flora which provides food and shelter to wild life destroyed.        

Prevention of Land pollution

• People should be educated and made aware about the harmful effects of littering.
• Items used for the domestic purpose should be reused or recycled.
• Inorganic matter such as paper , glass , plastics and metals should be reclaimed and then recycled.

 

Questions:

1. Industries are among the leading sources of air pollutant.

(a)    Name four substances from industries which contribute to air pollution.

(b)   Explain two other sources of air pollutants.

(c)    Give 3 effects of air pollution.

(d)   Explain how industrial worker can be protected against harmful chemical fumes.

 

2. (a) How is ozone formed?

(b) What are the causes of depletion of ozone layer?

(c) Explain harmful effects of depletion of ozone layer.

3. What is green house effect and what are its effects.
4. Write short notes on:-

(i)   Acid rain.
(ii)  Smog.
(iii)Environmental effect caused by mining.

5. What do you understand by the term Eutrophication and its causes? – How does it threaten the development of marine life?

ANSWER:

Q1.   (a)   Substances;-

. Carbon dioxide.

. Carbon monoxide.

. Methane.

. Sulphur dioxide.

(b)     Other sources:-

.  Burning fuels from car.

(c)     Depletion of ozone layer:-

.  Spread of air borne diseases  E.g. Tuberculosis.

.   Acid rain.

.   Global warming.

(d)  Industrial worker can be protected against harmful chemical fumes by:-

.  using protective masks to protect them from harmful fumes.

. Good ventilation systems in industries i.e.  air circulation.

. Close chambers for chemical processes.

2. (a) Ozone layer formation;-

 

(b) Causes of depletion of ozone layer

(a)    Natural destruction.

(b)   Artificial destruction.

 

 

 

(c) Harmful effects of ozone layer depletion

. It may result to skin cancer due to UV-rays.

. Damage immune system leading to increase in viral infection.

. Damage or death of marine plants and animals which are important to human survival.

 

3. – Green house effect

 

Is the process of trapping of heat in the atmosphere. This result in the overall increase in the average temperature of the Earth. The gases are the one’s which

trap the heat in the atmosphere.

 

– Effects of green house:–

. Leads to global warming. Ice caps will melt and this leads to increase in sea level which in turn lead to flooding (islands may disappear)

 

. Change in weather patterns (unpredictable weather)

 

4. (i) Effects of Acid Rain;-

    On Humans

. Irritation of the respiratory system.

. People with bronchitis become highly affected.

           On the Soil
.   Soil not having proper liming becomes highly acidic.
.  Acid rain may cause corrosion on buildings.
.  It can cause the death of micro organism in water bodies or on the land.

 

   Reactions for the formation of acidic rain

 

4.   (ii) Smog:  Contains soot, sulphur dioxide and other gases. It is usually found in cities.
5. Eutrophication:-

Is the process of adding of healthy adequate nutrition to water bodies or Addition of artificial or natural substances such as nitrates or phosphate through water
runoffs sewages etc. This increases number of marine plants such as phytoplanktons.

Causes of Eutrophication

• It is due to adding of nutrients such as Nitrates phosphates.

•   Runoffs from sewage.

•    Overflow of sanitary sewers.

•    Runoffs from industries.

•    Untreated sewage.

•    Overusing of pesticides and fertilizers.

•    Cultivation near water bodies.

Effects of Eutrophication
. Decrease of biodiversity

Death of marine organisms. This is because of depletion of oxygen. When the phytoplanktons  die, they decompose and marine organisms use up oxygen to
decompose them.  Hence the concentration of oxygen in water decreases which causes death of the marine organisms.
. Toxicity effect.

. Decrease in water transparency.

Questions:

1. Explain the meaning and significance of soil colloids.

 

2. Discuss the properties of soil colloids:

 

. Surface area.

 

. Electric charge.

 

. Ion exchange.

 

3. Explain the mechanism of ion exchange soil.

 

4. Describe cation exchange capacity of soil.

 

5. Calculation of percentage base saturation of a soil sample.

 

 

1.       6.  (a)   Why are the configurations of copper and chromium  peculiar?

(b)   Would you classify scandium and zinc as transition metal? Give the reasons for your answer.

 

(c)   When is copper considered as transition metal?

 

(d)  When does it not show transition behavior?

7.         (i)    Why are the elements with atomic numbers 21 to 30 classified together as a series in the periodic table?

(ii)    List the main characteristics of these elements and their compounds

8. Explain the following observations:-

(i) Water molecules readily coordinate with cations of the above series but Hydronium ion ( O⁺ ).
(ii) Addition of excess silver nitrate to an aqueous solution containing 0.01mole of Co C . 6 N  leads to immediate precipitation of 0.03moles of silver chloride. However, similar addition to an aqueous solution containing 0.01mole of Co C  leads to immediate precipitation of only 0.02 moles of silver chloride.