Chemistry class9 chapter 3 part 1

 Activity -1

 below is a table showing the mass of the reactants and the products when hydrogen combines with chlorine to form hydrogen chloride in two situations.

 Questio 1.
Write down the total mass of the reactants and also the total mass of product in the above experiment.
a) Situation 1: …………………
b) Situation 2: ……………….
Answer:
a) Total mass of reactants 73g products 73g
b) Reactants 146g products 146 g

Activity-2

Given below is a table showing the mass of the reactants and the products when hydrogen combines with oxygen to form watermolecules.

Write down the total mass of the reactants and the total mass of product in the above experiment.
a) Situation 1:
b) Situation 2:
Answer:
a) Reactants 18 g, Product 18 g
b) Reactants 36 g, Products 36 g

Question 3.
What is the relation between the total mass of the reactants and the total mass of products?
Answer:
Both are equal.

State The Law Of Conservation Of Mass

In a chemical reaction mass is neither created nor destroyed. This is the law of conservation of mass.
This law was proposed by the scientist Antoine Lavoisier. That is, the total mass of the reactants will be equal to the total mass of the products.

 Question 4.
A piece of magnesium is burned in air. 

a)What do you observe?
Answer:
It burns with sparkling light

b)What is the white powder formed?
Answer:
Magnesium oxide (MgO)

c)Which are the reactants here?
Answer:
Mg and Oxygen 

d)Which is the product?
Answer:
MgO

 
e)Note down the number of atoms in the reactant side and the number of atoms in the product side in the table below.

Answer:

f)Is the number of atoms of each element equal on both sides?
Answer:
No

g)The number of which atom is not equal on both sides?
Answer:
Oxygen 

h)How many product molecules are needed to equalize the number of oxygen atoms on both sides?
Answer:
2

i)How will you represent two molecules of magnesium oxide?
Answer:
2 MgO

j)Now, is the number of magnesium atoms equal on both sides?
Answer:
No

k)How many magnesium atoms are needed in the reactant side to equalize the number of magnesium atoms on both sides?
Answer:
2

l)Then how can you rewrite the above equation?
Answer:
2 Mg + O2 → 2MgO

m)Is the total number of atoms of each element in the molecules present in the reactant side and that in the product side equal in this equation?
Answer:
Yes

Question 5
What is balancing of equations?
Answer:
Equalizing the number of atoms of each element in molecules in the reactant side and that in the product side is called balancing of equation.

Question 6
Zn + HCl → ZnCl2 + H2
Tabulate the total number of atoms of each elements in the reactant side and that in the product side of the above reaction.

i)How many Zn atoms are there in the reactant side and in the product side?
Answer:
1 each

ii)Which are the atoms showing a difference in their number?
Answer:
H and Cl

iii)In order to make them equal on both sides how many molecules of HCI should be taken as reactant.
Answer:
2
Now rewrite the equation
Zn + 2HCl → ZnCl2 + H2

Question 6.
Balance the chemical equation H2 + O2 → H2O
Answer:
Step I: H2+ O2 → H2O
Step II: 2H2 + O2 → 2H2O

Question 7.
Balance the chemical equation Al + O2 → Al2O2
Answer:
Step I: Al + O2 → Al2O3
Step II: 4Al+ 3O2 → 2Al2O3

Question 8.
Balance the chemical equation H2 + O2 → H2O
Answer:

2H2 + O2 → 2H2O

Question 9.
Some chemical equations are given below. Note down the number of reactant atoms and that of product atoms in the table given below.
1. C + O2 → CO2
2. N2 + H2 → NH3
3. 2H2 O2 → 2H2O + O2
4. SO2 + O2 → SO3
5. BaCl2 + H2SO4 → BaSO4+2HCl

No.	Reactant atoms	Product atoms
1	C-1, O-2	C-1, O-2
2	N-2, H-2	N-1,  H-3
3	H-4, O-4	H-4, O-4
4.	S-1, O-4	S-1, O-3
5.	H-2, S-1, O-4,	H-2, S-1,O-4,
	Ba-1 Cl-2	Ba-1, Cl-2

Balance the equations which are unbalanced
Answer:
1. N2 + 3H2 → 2NH3
2. 2SO2 + O2 → 2SO3

Oxidation And Reduction

Question 10.
The electronic configuration of magnesium and chlorine are 2, 8, 2 and 2, 8, 7 respectively. How many electrons does a magnesium atom donate? What charge will it get?
Answer:
2, two positive (2+)

a)Let us complete the equation for this process,
Mg → Mg2+ + ……………
Answer:
Mg → Mg2+ + 2e–

b)How many electrons are accepted by each chlorine atom? What will be the charge acquired by each atom?
Answer:
One,  1– (Cl1-

c)Complete the equation of this process.
Cl + 1e– →
Answer:
Cl + 1e– → Cl1-

d)What are oxidation and reduction?
Answer:
Oxidation is the process of loss of electrons. Reduction is the process of gain of electrons. The atom which loss electron is called the reducing agent and the atom which gains electron is called the oxidizing agent.

Question 30.
In the above chemical reaction, which atom is oxidized?
Answer:
Sodium

Question 31.
Which atom is reduced?
Answer:
Chlorine

Question 32.
Which is the oxidizing agent in this chemical reaction?
Answer:
Chlorine (Cl)

Question 33.
Which is the reducing agent in this chemical reaction?
Answer:
Sodium (Na)

Question 34.
Analyze the following equations and list the oxidized atom, reduced atom, oxidizing agent and reducing agent.
a) Mg + F2 → MgF2
b) 2Na + Cl → NaCl
Answer:
a) Oxidized atom — Mg
Equation of oxidation — Mg → Mg2+ + 2e–
Reduced atom — F
Equation of reduction — F + e– → F–
Oxidizing agent — F
Reducing agent — Mg

b) Oxidized atom — Na
Equation of oxidation — Na → Na + 1e–
Reduced atom — Cl
Equation of reduction — Cl+ 1e– → Cl–
Oxidizing agent — Na
Reducing agent — Cl

Question 35.
Analyse the following equations and complete the Table given below.
1. Mg → Mg2+ + 2e–
F+ le– → F–
2. Na → Na++1e–
Cl + 1e– → Cl–
3. Fe → Fe2++ 2e–
O + 2e– → O2–

Answer:

Equation of oxidation	Reducing agent	Equation of reduction	Oxidizing agent
Mg → Mg2++ 2e–	Mg	F + 1e–→ F–	F
Na → Na++1e–	Na	Cl + 1e → Cl–	Cl
Fe → Fe2++ 2e–	Fe	O + 2e– → O2-	O

 The trade routes connected the East and the West. Substantiate.

Answer:

The continents which mainly locate in the West are Europe, North America, and South America. The Eastern countries which are mentioning in this units are Arabia just adjacent of Africa, India, China and so many other countries of the Asian continent. The continents in between the Atlantic Ocean, the Indian Ocean, and the Pacific Ocean are broadly classified into the East and the West.

The silk which produced abundantly in the East was famous for its quality, color, and transparency. This silk was so dear to the Europeans. They were ready to travel to the East either via the sea route or through the land route to secure the spices, that were in plenty in the Eastern countries. ?These species were cardamom, pepper, ginger, and cinnamon, sandalwood, and forest resources were also the favorite items of the Europeans.

They frequently traveled through these routes to and fro with the purpose of trade. Later these routes were known as trade routes. The silk route through the land and the spice route through the sea helped a lotto the mutual transaction of the varied cultures of the East and the West. Thus these trade routes paved the way to connect the East and the west. They also helped a lot to the transaction of the resources and various products or trade and the togetherness of various cultures.

Question 

Examine the circumstances that led to the growth of distant trade?

Answer:

Our earth is a combination of so many countries generally seen in between the oceans and the land. There are a wide range of differences in climate, resources, minerals, food and cash crops, people and their lifestyles among these countries. Each and every country is not at all self-sufficient in all types of resources or products. The products produced in the places where the nearness of the sea is a key factor are not alike that of the products of the continents. So in the ancient period onwards, people were eagerly enquired about the various products that were produced in the various parts of the world.

Some times, it was too difficult to reach in the remote areas of those countries form a distance. But the traders from various countries decided to travel to those distant countries. Thus the distant trade flourished. The traders competed among

What are the causes for the transformation of cities into trade centers?

Answer:

The traders searched for better places which were suitable for trade. Their main priorities were trans-portation and warehouse facilities. Several traders came together to a place from where they could get a lot of products. So many people accompanied them to get job. Some others came there with a purpose of retail trade. This continuous flow of people to a particular trade center, it gradually developed into cities.

Most of the medieval cities were grown and developed in the banks of the rivers. The facilities of transportations, large scale collection of various articles, smooth transactions, the support of the rulers boosted the growth of the cities. Later these cities became the centers of trade. Increase in population made those cities into highly populated and busy trade centers.

Question 

Prepare a note on the progress in the field of science and technology in the medieval world.

Answer;

During the medieval period, science attained progress.

Contributions were given to medical science.

Surgery began.

Paved the way for the invention of automobiles and aircraft.

Notable contributions were made in astronomy.

The crusades facilitated the exchange of scientific and technological knowledge.

Making telescope, mechanical clocks, principle of the gear, surgical instruments, etc. were the achievements of this period.

Algebra, Alchemy, Trigonometry were other achievements.

Street lights of the cities and waste management programmes were the contributions of this period

Question 

Name the Italian cities that emerged commercial centers from 1050 to 1300 CE.

Answer:

Genoa

Venice

Pisa

Florence

Question 

Identify the factors that led to the decline of guild system.

Answer:

Industrialization

Growth of science and technology

Question 

Which are the towns where the Italian traders had the trade relations?

Answer:

Baghdad

Damascus

Jerusalem

Question 

What were the suitable situations that caused development and progress in trade to Italian cities like Florence, Venice, Genoa, and Pisa compared to other European regions?

Answer:

They began to mint their own coins.

The presence of ports Italian sub-continent

The concessions provided their merchants

Encouragement from administrators.

Question 

Bring out factors that strengthened the commercial contacts between the East and the West in the medieval period?

Answer:

The comparatively weak trade between the East and the West got a fillip with the beginning of the crusades.

The Italian traders were engaged in long-distance trade with Eastern Roman Empire and the Arabs.

They had trade relations with towns like Baghdad, Damascus, and Jerusalem.

The rapid increase in production, diversity of products, construction of roads and bridges, and effective steps to control thieves and robbers resulted in the strengthening of the commercial contracts between the East and the west.

Question 32.

Name the important guilds existed in Medieval Europe.

Answer:

Carpenters

Leatherworkers

Blacksmiths

Jewelry makers

Sewing laborers

Question

What is meant by Carolingian Renaissance?

Answer:

The cultural and intellectual awakening of the 8th and 9th century medieval Europe had been generally characterized as the Carolingian Renaissance.

Question 

“The crusades influenced the wester life” Do you agree? Justify.

Answer:

Yes, I agree with this statement.

The Europeans got acquainted with the Islamic culture during the Crusades. Art and literature were exchanged during this period. The western style was profoundly influenced by the Eastern art and architecture. The Platonic Academy of Florence and the Quinze-Vingts hospital of Paris constructed by the French emperor Louis IX on his return from the crusades are examples

Biosphere Reserves in India
There are 18 biosphere reserves in India, which are:

S. No.
Name
State
10
Achanakmar-Amarkantak Biosphere Reserve
Madhya Pradesh, Chhattisgarh
14
Agasthyamalai Biosphere Reserve
Kerala, Tamil Nadu
12
Cold Desert
Himachal Pradesh
16
Dibru-Saikhowa
Assam
8
Dihang-Dibang
Arunachal Pradesh
15
Great Nicobar
Andaman and Nicobar Islands
11
Great Rann of Kutch
Gujarat
3
Gulf of Mannar
Tamil Nadu
13
Khangchendzonga
Sikkim
6
Manas
Assam
2
Nanda Devi Biosphere Reserve
Uttarakhand
1
Nilgiri Biosphere Reserve
Tamil Nadu, Kerala and Karnataka
4
Nokrek
Meghalaya
9
Pachmarhi Biosphere Reserve
Madhya Pradesh
18
Panna
Madhya Pradesh
17
Seshachalam Hills
Andhra Pradesh
7
Simlipal
Odisha
5
Sundarbans
West Bengal
Endemic Species
Species: A group of living organisms that can interbreed with each other are called a Species. It means that only members of one species can reproduce offspring that are fertile and can give birth to future generations. Members of a species look like each other and share many characteristics.
Endangered Species: Species whose number diminish so much that they might face extinction (or vanish off the face of the Earth) are known as Endangered Species. There can be endangered animals as endangered plants.
Endemic Species: Species of plants and animals that are exclusively found in a particular area are called Endemic to that zone, state or country. The endemic species are not found anywhere else naturally.
For Example:
Endemic flora of the Pachmarhi Biosphere Reserve includes sal and wild mango.
Sal
Wild Mango
Endemic fauna of the Pachmarhi Biosphere Reserve includes bison, Indian giant squirrel and flying squirrel.
Bison
Wild Mango
Flying Squirrel
Wildlife Sanctuary
Wildlife Sanctuaries are reserved forests where wild animals are protected and provided with suitable living conditions. Unlike a zoo, animals in wildlife sanctuaries live in their natural habitat and are free to roam anywhere as they like.
People living in Wildlife Sanctuaries can:
Graze livestock, and
Collect firewood or medicinal plants.
Activities prohibited in wildlife sanctuaries include:
Killing (poaching) animals
Capturing animals
These activities in wildlife sanctuaries are punishable by law.
Wildlife Sanctuaries in India
Indian wildlife sanctuaries have unique landscapes which include broad-level forests, mountain forests, and bushlands in deltas of big rivers. They protect several threatened wildlife species such as golden cat, pink-headed duck, black buck, white-eyed buck, gharial, marsh crocodile, elephant, rhinoceros, python etc.
Unfortunately, people encroach upon the land of these protected forest areas and destroy them.
There are 543 wildlife sanctuaries in India, which include as many as 50 tiger reserves which focus on the conservation of the tiger. The tiger reserves work under Project Tiger. Jim Corbett was the first tiger reserve of India. It is situated in Uttarakhand and is also the oldest national park in India.
Project Tiger is a government initiative to protect tigers. Its objective was to ensure the survival and maintenance of the population of tigers in India.
Similarly, some of these wildlife sanctuaries are called bird sanctuaries as they focus on protecting birds. Keoladeo National Park, for example, was a bird sanctuary before it attained the National Park status.
Some national parks focus on conserving a particular species, For Example, Jawai leopard sanctuary which is in Rajasthan.
National Park
National Parks are large forest reserves that attempt to preserve the entire ecosystems within the area including the landscape, flora, fauna, and historic objects of the area.
Satpura National Park is the first Reserve Forest of India. Within this forest, you can find the finest Indian teak as well as rock shelters which are evidence of the prehistoric human life in the area.
There are a total of 55 rock shelters in Pachmarhi Biosphere Reserve which also feature rock paintings depicting figures of men fighting with animals, hunting scenes, dancing, and playing musical instruments. Many tribal are still living in the area.
National Parks in India
There are 104 national parks in India. Top 10 of these national parks include:
Jim Corbett National Park, Uttarakhand
Kaziranga National Park, Assam
Gir Forest National Park, Gujarat
Sundarban National Park, West Bengal
Satpura National Park, Madhya Pradesh
Eravikulam National Park, Kerala
Pench National Park, Madhya Pradesh
Sariska National Park, Rajasthan
Kanha National Park, Madhya Pradesh
Ranthambore National Park, Rajasthan
Why do animals become extinct?
Disturbances in the natural habitat of animals make it difficult for them to survive and hence, become extinct. For Example, dinosaurs became extinct thousands of years ago.
Why do we need to conserve animals?
Animals, such as lizards, snakes, owls, and bats, play a particular role in an ecosystem and help in maintaining its balance. They form part of food chains and food webs. We need to conserve different life forms to make sure that the natural balance does not get disturbed.
What do we mean by an ecosystem?
An ecosystem refers to the living organisms and non-living components of a place, including plants, animals, microorganisms, climate, soil, river deltas etc.
Red Data Book
International Union for Conservation of Nature (IUCN) maintains a record of all the endangered animals and plants in the world and calls it Red Data Book. India also maintains its own Red Data Book which keeps a record of endangered plants and animals found in India.
The Golden Toad now makes the Extinct as well as the Extinct in the Wild lists of the IUCN Red List.
There is a Red Data List too, which is also known as IUCN Red List of Threatened Species or IUCN Red List which classified all known plant and animal species into nine groups:
Extinct: No known individual of the species is alive.
Extinct in the Wild: No known individual of the species in the wilderness. They exist only in captivity.
Critically Endangered: Species that are at extremely high risk of being extinct in the wilderness.
Endangered: Species that are at high risk of being extinct in the wilderness.
Vulnerable: Species that are at high risk of being endangered in the wilderness.
Near Threatened: Species that are likely to become endangered in the near future.
Least Concern: Species which are found in abundance and is not at risk.
Data Deficient: Species about which we do not have enough data to assess its extinction risk.
Not Evaluated: Species which has not yet been evaluated on the criteria adopted by the IUCN.
Species that fall in the Critically Endangered, Endangered and Vulnerable categories are also referred to as Threatened Species.
Migration
Migration is the movement of birds, animals or humans over long distances to live in a new location permanently or temporarily.
Migratory birds are birds that fly to far away areas every year to avoid harsh and inhospitable weather conditions in their natural habitat. They cover long distances to reach another land and lay their eggs.
Recycling of Paper

Why should we recycle paper?
We need to cut 17 full-grown trees to make one tonne of paper. We can easily reuse and recycle paper for five to seven trees. Reducing our consumption of paper can save trees and also save water and energy used to manufacture paper.
Besides, it can also help in reducing the use of harmful chemicals that are used to make paper.
Reforestation
Reforestation is the opposite of deforestation. Here, we plant new trees to restock forests that have been destroyed.
In India, we have the Forest (Conservation) Act which aims to preserve and conserve natural forests and meet the basic needs of the people living in or near them.
Reforestation can happen naturally or can be done artificially. If a deforested area is left undisturbed for some time, the forests grow again. However, we cut more trees than the ones that grow on their own and hence, we should plant trees to promote reforestation.
Ideally, we should plant as many trees as had been cut down and the new trees should be of the same species as the earlier ones.