Share this:


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.
i) Agricultural chemicals .
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.
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: –
i) Management waste.
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 c
limate 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.

i) Sources of water pollution
The major forms and the sources of water pollution are: –
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.
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.

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.
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:
a) Management of water treatment of drinking water, industrial water ,sewage or waste water .
b) Management of water resources.
c) Management of irrigation.
Treatment of water maybe divided into two;-
i) Purification of domestic use.
ii) Treatment for specialized industrial application.

2. 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
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.
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.
eg. 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.
i) Effects on human health
Severe air pollution cause many fatal diseases and disorders some of the effects caused by inhaling polluted air are: –
a) Sulphur dioxide enters soft tissues causing drying of the mouth, scratchy throat and smarting eyes.
b) Hydrocarbons and many other air pollutants cause skin cancers.
c) Oxides carbon , sulphur , nitrogen diffuse into the blood and combine with haemoglobin causing reduction in it is oxygen carrying capacity.

ii) Effects on vegetation
Air pollution has serious harmful effects on vegetation.

Effects of air pollution on vegetation are :-
a) Sulphur dioxide causes chlorosis i.e. loss of effects on tress , plants and vegetation.
b) Oxides of nitrogen and fluorides reduces crop yields.
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


GENERAL QUESTIONS

1. 9. (a) Give the meaning of second order reaction and derive the units of its rate constant
(b) The reaction between Br and B in acidic medium is given by the equation.
Br(aq) + 5B(aq) + 6 (aq) → 3B(l) + O(l) .

The following table gives the results of four different experiments
Experiment. No
1
2
3
4
Br
Br
H+
0.2
0.2
0.2
0.4
0.2
0.2
0.4
0.4
0.2
0.2
0.2
0.4
Initial rates
1.56×10-2
2.56×10-2
5.12×10-2
5.12×10-2
Calculate:
(i) Order of reaction with respect to each reactant
(ii) The value of rate constant
2. 10. (a) Briefly explain the meaning of:
(i) Metallurgy
(ii) An ore
(b) Describe the essential steps used during extraction of tin(Sn) show clearly the reaction equations
3. (c) Indicate the structure of monomers and polymerization method which is likely to be used in making of each of the following commercial polymer
(d) Describe the preparation of benzanamine benzene
(e) Write the chemical equation to show how propanamine reacts with
(i) Mixture of trichloromethane and potassium hydroxide
(ii) Ethanoic acid
(iii) Chloromethane

ANSWERS:
9.(a) Second order reaction is the reaction in which the rate of reaction is proportional to the Second power of concentration of a single reactant

or first powers of concentration of two reactants.
(b) Solution:
(i) R = K [Br O3] x [Br] y [H] 2
=

K= 1
=
= y
y = 1
=
= X
=
=

Z = 1, Y = 1, Z = 2
I, 12
(ii) Solution:
R = K
1.28×10 –L = K



10. (a) Ore
(b) Solution:
The ore in which tin is extracted is called cassiterite (Sn)
Concentration of ore:

Cassiterite is pulverized in ball mills. Magnetic impurities such as Fe and Mn are separated out by magnetic separation while other

impurities are removed by Wilfley’s table or hydraulic classifier method. This is done in a reverberatory furnace excess supply of air where

volatile impurities are given out. Impurities of sulphur and arsenic are volatized away.
M + M
M = As, 5b
S + S
Smelting:
In this process, there is reduction of tin oxide to tin using coal. Temperature should be around 1200 to 1300
But some of the tin oxide will give SnO which will react with silica to form slag

Purification:

This is done in a chamber with no entrance of oxygen

(b) Solution:


N N

+ H N
Benzene benzanamine
(c) Solution



1. 11. (a) (i) State the partition law
(ii) Write down the conditions for the law above to hold
(iii) The partition coefficient for iodine between water and C at 20 is 2.43×10-3 .A 100 cm3 sample of solution of iodine in O of conc 1.00×10-3 M is shaken with 10.00 cm3 of C. What fraction of iodine is extracted by C.

(b) Define precisely the following terms:
(i) Standard molar enthalpy of formation
(ii) Heat of solution of a substance
(iii) Ionization energy
(c) (i) State Hess’s law of constant heat summation

(ii) Calculate the standard heat of formation of carbon-monoxide if standard heat of combustion of carbon and carbon monoxide are 393 KJ

mol-1 and – 285 KJ mol-1 respectively.


(iii) Determine the enthalpy change for the isomerization reaction:
The heat of formation of OH is = 276 KJ mol-1
The heat of combustion of C – O – C is = 1456 kJmol-1
The heat of formation of O is =284 KJ mol-1
The heat of combustion of carbon is =394 KJ mol-1
2. 12. (a) Explain the meaning of the following and give one example:
(i) Nucleophilic addition reaction

(ii) Nucleophilic substitution reaction

(iii) Elimination reaction
(b) How can you distinguish the following compounds

(c) Illustrate the preparation of the following compounds

(i) Propanoic acid from ethane
(ii) Propan – 2 – ol from propan -1-ol
(iii) Propyne from ethyne

13.(a) Explain the following with vivid example and relevant chemical equations.
(i) Li and Mg are more related chemically than Li and Na although both Li and Na are group I
(ii) F is the most oxidizing element of all in the periodic table
(iii) Electron affinity of F is unusually low
(b) Distinguish between the following:
(i) Coordination number and oxidation number
(ii) Paramagnetism and ferromagnetism
(iii) Strong ligand and weak ligand

ANSWERS:
1. 11. (a) (i) Partition law:
“When a solute is dissolved in a mixture of two immiscible solvents, it distributes itself in a constant ratio of concentration”.
(ii) Conditions
1.The two solvents must be completely immiscible.
2. Temperature should be constant.
3. There should be no change in molecular state of the solute i.e. should not dissociate or associate in any of the solvents.
(b) (i) Standard molar enthalpy of formation:
Is the heat change when 1 mole of a substance is formed from its elements in their standard states.
(g) + (g) N (g)
Heat of solution of a substance:
Is the enthalpy change when 1 mole of a substance is added to so much water that further addition of water produces no farther change.

Ionization energy:
Is the energy required to remove the most loosely held electron from the shell of an atom or ion.

(c) (i) Hess’s law:
The enthalpy change for a particular reaction is same whether the reaction takes place in one step or in a series of steps.
(ii) Solution:
Applying Hess’s law
HC = -393 KJ mol-1
HC = +285 KJ mol-1
K.D =
0.0243a = 10-4 -a
1.0243a = 10-4
a = 9.76×10-5 moles
Fraction of Iodine extracted by C will be
= 9.76 x 10-5
1 x 10-4
= 0.976
(iii) Solution:


12.(a) (i) Nucleophilic addition reaction is the reaction in which nucleophile is added
First followed by electrophile.
Elimination reaction is the reaction whereby an atom or group of atoms are removed from a compound
e.g: C C Cl + NaOH C + NaCl + O
C C and C CC
OH
By Lucas Test
Propanol will not form cloudness when it undergoes Lucas test but propan -2-ol will form cloudness after 5 minutes upon Lucas test.


(ii) C CH – C and C C C Cl
Using KOH followed by AgN in the presence of HN, yellow ppt will be observed for C C CCl while there is
Cl
No reaction for C CH C
(iii) C C CHO and C C – C C
C C CHO will react with Tollen’s reagent [Ag (N]OH to form a white ppt of silver at the bottom of the test-tube while
CC C – C C will not react.
(c) (i) Propanoic acid from ethane
C CN + O 4 C C – N CH3 C– OH
Propanoic acid
(ii) Propan-2-ol from propan-1-ol
CC C OH + S C CH = C
(iii) Propyne from Ethyne
λ m =
= 133 S cm3 mol
= 6.4×10-3 g cm-1
C = 5 X 10 -2 M
=

1 dm3 = 10 3 cm3
x =1cm3
= 10-3
= =
= =
= 128 S cm-2 mol-1
= O.96

13. Salt hydrolysis is the reaction between salt and water to form an acidic or alkaline solution:
Order of reaction: Molecularity:
– It cannot be determined – Can be determined from the equation
From equation (determined experimentally).
– It can be a whole number or fraction . – It can only be a whole number
– It is the sum of concentrations terms on – It is the number of ions atoms or
Which the rate of reaction actually depends molecules that must collide so as to
(It is sum of exponents of the concentrations results in a chemical reaction.
in the rate law).
– It cannot be obtained from the stoichiometry – It can be obtained from the
Of an unbalanced equation. Stoichiometry of the equation.
= 30 x 60 = 1800s at 27
= 10×60 = 600s at 47
Log =
n log =
log = – 1.088 x 10-5 Ea
= Ea = 4.3833
K =
K =

K = 3.85×10-4
Tollen’s reagent (silver mirror test)
Acyl halides (Acid halide)

Derivatives of carboxylic acids upon hydrolysis go back to carboxylic acids

Transesterification is the reaction between ester and alcohol to form another ester

Conditions for a chemical reaction to take place
i. The collision of the molecules must be energetic enough to break the bonds between the molecule
ii. The colliding molecule must have right orientation (geometry)
Log K1 = log A –
Log K2 = log A –
Log K1 –log K2 =
Log =
In = Kt =
= Kt =
Homolytic bond cleavage.
Is the type of bond cleavage in which the covalent bond breaks symmetrically so that are electron moves to each end.
Heterolytic bond cleavage.
Here the covalent bond breaks unsymmetrical and all bonding electrons are taken by the more electronegative atom


(g) + → 2N Slow
R= [] [] this slow step will determine rate law
= [NO] [NO]
= [NO
= []
At equilibrium =
[NO] 2 = []
[NO] 2 = []
R= [NO]2 []
R= K [NO]2 []
The slow step will determine the rate law
R = [Br] []
Consider the equilibrium reaction

= [B]
= [Br] 2
At equation:
=
[B] = [Br]2
[B] =[ Br]2
[Br] = [Br]1/2
R= K0Br1/2
R= K [Br []
Kh =
CCOONa → CCO + N
Start 0.1 0 0
0.1 – x x x
Kh =
α = × 100
[H COONa] =
Let added volume be x
[H COONa] =
0.1=
n=0.1x
[H COONa] =
[HCOOH] =
14. Explain the meaning and significance of colloids

15. Discuss the properties of soil colloids
– Surface area
– Electric charge
– Ion exchange (diagram)

16. Explain the mechanism of ion exchange in soil

17. Calculation of percentage base saturation of a soil sample. With worked examples (how to calculate)

18. Aluminum has high polarizing power hence the compound formed between Al and carbon will be unstable therefore it will decompose immediately after formation.
The chloride outside is not part of the complex meaning that it is ionization. Therefore Ag will react. In [ p(NH3)2 cL4)] the chloride is part of the complex hence there is no ionizable chloride ion and there no reaction


19. (a)(i) CH3 – C-CH3 + CH3 Mg CL CH3 –C- CH3


(ii) CH3 –C- C-CH3 +NaOH + I2 CHI3 + NaOOC – CONa + NaI
(iii) CH3 CH2 C – NH2 CH3 CH2 NH2 + KBr +CO2 +H2O
(iv) CH3 CH2 NH2 + CHcL3 CH3 CH2 N =C + HCL


20. Distinguish between
When Br2/H2O is added to phenol, white ppt is formed

When Br2/H2O is added, no reaction


(iv) CH3 CH2 OH +I2 + NaOH No reaction

22. With the aid of chemical equations explain the following
(i) Mercury(ii) iodide solution but not in potassium iodide solution but in water
(ii) The pink solution of cobalt (ii) chloride turns blue when conc. HCL is added gelatinous ppf of

(iii) Copper (ii) hydroxide turns deep blue in excess ammonia

(iv) ZnO and Pbo dissolves in hot conc sodium hydroxide solution
23. using relevant balanced chemical equation describe the process of extracting copper from copper pyrite under the following headi
ng.
(i) Concentration

(ii) Roasting
(iii) Removal of ion impurities

(iv) Self- reduction reaction

24. Cobalt copper, Iron and manganese are d-block elements
a. What is meant by the term d- block element
b. Write E.C of Cu, Fe2+, Mn2+
(i) Explain in terms of E.C why Fe2+ ions are readily oxidized to Fe3+ ions but manganese (ii) ions are not readily oxidized to Mn3+
25. 2.5 x 10-3 moles of a compound with a formula was dissolved in 0.1M a silver nitrate solution. 50 cm3 were required for complete precipitation of the chloride ions present.
(i) Deduce the ionic formula of the compound
(ii) Draw the structure of the complex ion present and name it
26. Write the formula of the following complexes
(i) Tetra ammine copper(ii) Sulphate mono hydrate
(ii)Potassium
27. Write down a balanced chemical equation for the following
(i) Adding of excess ammonia solution to aluminium ion
(ii) Ion(iii) oxide is heated with aluminium power




Share this:


subscriber

Leave a Reply

Your email address will not be published. Required fields are marked *

Accept Our Privacy Terms.*