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Carbon and it's compounds mega question series

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Q1.How much percentage of earth’s crust constitutes carbon element ?

Ans. The earth’s crust has only 0·02% of carbon in the form of minerals.

Q. 2. What do you mean by covalency ?

Ans. Covalency is defined as the number of electrons shared by an atom.

Q. 3. What is covalent bond ?

Ans. A bond formed by the sharing of electrons is called covalent bond.

Q. 4. What is functional group ?

Ans. A functional group is an atom or a group of atoms that characterizes the chemical properties of an organic compound.

Q. 5. What is organic chemistry ?

Ans. The branch of chemistry that deals with study of compounds of carbon except for oxides of carbon, carbonate and hydrogen carbonate salts is called organic chemistry.

Q. 6. What are Hydrocarbons ?

Ans. These are the compunds of carbon and hydrogen are called hydrocarbon.

Q. 7. What are saturated carbon compounds ?

Ans. The compunds of carbon in which carbon-carbon atoms are linked by single covalent bond are called saturated carbon atoms; Alkanes.

Q. 8. What are unsaturated carbon compunds ?

Ans. The compounds of carbon in which carbon-carbon atoms are linked by multiple bonds i.e. double or triple bonds are called unsaturatedcarbon compounds, e.g : Alkenes or Alkynes.

Q. 9. Define Allotropy.

Ans. The phenomena by virtue of which an element can exist in two or more than two forms having similar chemical properties but different physical properties is called allotropy.

Q. 10. What is vinegar ?

Ans. Vivegar is 5–8% solution of acetic acid in water.

SHORT ANSWERS TYPE QUESTIONS 2 Marks each

1.What is combustion ?

Ans. It is the process of burning of a substance in the presence of oxygen to produce carbon dioxide along with heat and light.Combustion reactions are also called oxidation reactions.

e.g. : CH4 + O2 ——> CO2 + H2O + Heat and light

2. Write two differences between oils and fats.

Ans. Oils : 1. Oils are liquid at room temperature 2. Oils contaning unsaturated fatty acids.

Fats : 1. Fats are solid at room temperature. 2. Fats containing saturated fatty acids.

3. Define Esterification ?

Ans. It is the process of formation of ester by the reaction between an alcohol and an acid is called esterification. e.g. : Reaction between ethanol and ethanoic acid in presence of conc. H2SO4.

CH3COOH + C2H5OH ——> CH3COOC2H5 + H2O

Ethanoic acid Ethanol Ethylethanoate Water

4. What is saponification ?

Ans. It is the alkaline hydrolysis of esters to give back the carboxylic acid and alcohol. As it is used in the prepation of soap, it is called saponification.

CH3COOH + NaOH ——> CH3COONa + C2H5OH

Ethanoic acid Sodiumhydroxide Sodiumethanoate Ethanol

5. Which of the following hydrocarbons undergo addition reactions :
C2H6, C3H8, C3H6, C2H2and CH4.

Ans. Unsaturated hydrocarbons, i.e., Alkenes and alkynes undergo addition reactions. Alkenes and alkynes have general formula CnH2n and CnH2n -2.

Thus compounds — C3H6 (propene) and, C2H2 (ethyne) ; undergo addition rections.

6. How can you differentiate saturated and unsaturated Hydrocarbon on the basis of burning behaviour ?

Ans. On burning, saturated hydrocarbons give a clean flame whereas unsaturated Hydrocarbons on heating give a yellow flame with lots of black smoke.

7. Write two ill-effects of drinking excess of alcohol ?

Ans. (1) Alcohol causes addiction and makes person dependent on it.

(2) If consumed in large quantities, it may cause death by damaging liver.

8. What is denatured alcohol ?

Ans. Alcohol which is made unfit for the drinking purposes is called denatured alcohol. It is ethyl alcohol (C2H5OH) mixed with poisonous substances like methanol, copper sulphate, etc.

9. Give two advantages of synthetic detergents over soaps ?

Ans. (1) Synthetic detergents can be used with hard water also whereas soaps cannot with hard water.

(2) Synthetic detergents are more soluble and have better cleansing action than soaps.

10. What are substitution reactions ?

Ans. It is a type of reaction in which a chemical reagent (substituent) displaces the another atom or group (leaving group) in a compound, e.g., Substitution of Hydrogen of Methane by chlorine

CH4 + Cl2 --Sunlight ----------> CH3Cl + HCl

Methane Chlorine Methyl Chloride Hydrogen Chloride

or

Chloramethane

SHORT ANSWERS TYPE QUESTIONS 3 Marks each

1. Differentiate between diamond and graphite.

Ans. Diamond :

1. Diamond has 3-dimensional network structure.

2. Each carbon in diamond is bonded to four other carbon atoms.

3. No free electron is left.

4. It is a bad conductor of electricity.

5. It is hard.

Graphite :

1. Graphite has hexagonal sheet layer structure.

2. Each carbon atom in graphite is bonded to three other carbon carbon atoms.

3. Each carbon has one free electron with it.

4. It is a good conductor of electricity.

5. It is soft and slippery.

2. How is combustion different from pyrolysis ?

Ans. Combustion means heating a compound in the presence of excess or limited supply of air, e.g., combustion of methane gives carbon dioxide and water.

CH4 + O2 ——> CO2 + H2O + Heat and light.

Pyrolysis means the decomposition of a hydrocarbon into its element on strong heating in the absence of air, e.g. : Pyrolysis of methane gives carbon and hydrogen.

CH4 ------100°C-------------> C + 2H2

In abesebce of air

3.Discuss the method of preparation of soap in the laboratory.

Ans. In laboratory, soap is prepared by heating of equal volumes of castor oil and concentrated sodium hydroxide solution taken in a beaker. A paste of soap is formed by constant stirring during heating. Most of the soap separates out but some of it remains dissolved in solution. NaCl is then added to precipated out all the soap from equeous solution. On cooling the solution, solid soap separates out.

Glycerl Oleate + Sodium ---Heat -> Sodium Oleate + Glycerol

Glycerol is obtained as a byproduct in this process.

4. Write five ill effects of alcohol drinking.

Ans. (1) Alcohol is an intoxicant and its drinking result lose in the sense of discrimination.

(2) It ruins the health of the person by damaging liver and making his brain dull.

(3) Alcohol drinking by the head of a family worsens the economic condition of the family.

(4) The alcohol drinking by the head of a family has very bad effect on the psychological development of the children.

(5) Drinking adulterated alcohol causes blindness or even death.

5. Differentiate between soaps and synthetic Detergents.

Ans. Differences between soaps and synthetic detergents :

Soaps :

1. They are the sodium salts of the long chain carboxylic acids. The ionic group in soaps is – COO Na

2. Soaps have relatively weak cleansing action.

3. Soaps are prepared from animal fats or vegtable oils.

4. They are not suitable for washing clothes in Hard water.

5. Soaps are biodegradable.

Synthetic Detergents :

1. Synthetic detergents are the sodium salts of long chain benzene sulphone acids or long chair alkyl hydrogen sulphate. The ionic group in a synthetic detergent is — SO3Na or —SO4—Na+.

2. Synthetic detergents have a strong cleasing action.

3. Synthetic detergents are prepared from the hydrocarbons.

4. Synthetic detergents can be used for washing clothes even in Hard Water.

5. Synthetic detergents are non-biodegradable.

6. Differentiate between ionic compounds and covalent compounds.

Ans. Difference between ionic compounds and covalent compounds :

Ionic compounds :

1. Ionic compounds have constituents particles called ions.

2. In these compounds the ions of opposite charge are held together by strong electrostatic forces of attraction.

3. They have high melting and boiling points.

4. These conduct electricity in solution or in molten state.

Covalent compounds :

1. Covalent compounds have constituent particles called molecules.

2. In these compounds the molecules are held together by weak attractive forces.

3. They have low melting and boiling points.

4. These are largely non-conductor.

7. Give some important properties of ethanol (ethyl alcohol).

Ans. (1) Ethanol (C2H5OH) is highly soluble in water.

(2) It is a colourless liquid at room temperature.

(3) It has very low melting point (156 K).

(4) It has low boiling point (351 K or 78ºC).

(5) It is one of the main components of alcoholic drinks.

(6) It is a good organic solvent.

(7) Ethanol alcohol reacts with Na metal vigorously to evolve H2 gas.

2C2H5OH + 2Na ——> 2C2H5ONa + H2 (g)

Sodium ethoxide

(8) It burns with blue flame in the presence of O2 of air. This combustion is an oxidation process.

C2H5OH + 3O2 -Combustion ----->2CO2 + 3H2O + Heat and light

8. Give five main advantages of synthetic detergents over soaps.

Ans. Following are the advantages of synthetic detergents :

1. Synthetic detergents can be used even with hard water but soaps cannot be used with hard water.

2. Synthetic detergents have a stronger cleansing action than soaps.

3. Synthetic detegents are more soluble in water than soaps.

4. Synthetic detergents are prepeard from the hydrocarbons white soaps are prepared from from animal fat or vegetable oil which leads to their deficiency for human consumption.

5. Synthetic detergents can be used even in acidic solution but not the soaps.

9. Write important uses of (a) ethanol and (b) ethanoic acid.

Ans. (a) Uses of ethanol :

(1) Ethanol (ethyl alcohol) is used for making alcoholic drinks like wines, whiskies, beer, etc.

(2) It is used for making wood polish.

(3) It is used for making some medicines like cough syrups, tincture iodine and some tonics.

(4) It is used for making antifreeze material for cooling engines of vehicles.

(b) Uses of ethanoic acid :

(1) Dil. solution of ethanoic acid (acidic acid) in water is called vinegar, which is used as a preservative of pickles.

(2) It is used as a useful reagent in the chemical laboratories.

(3) It is used for making many C– compounds.

(4) It is used for making esters which are used as flavouring agents and perfumes.

10. What happens when ethanol reacts with (i) sodium (ii) potassium permanganate solution.

Ans-(i) with sodium metal ,sodium ethoxide formed.

2CH3CH2OH+2Na ------------> 2CH3CH2ONa + H2

(ii) With alkaline potassium permanganate, ethanol is oxidised to ethanoic acid.

CH3CH2OH+2[O] --------> KMnO4 ---Dil.H2SO4 -----> CH3COOH + H2O

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Class 10 Co-ordinate Geometry Mega Question Series

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Ch 7 Print Culture and the Modern World Class 10th Notes| History Social Science

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Ch 7 Print Culture and the Modern World Class 10th Notes| History Social Science

The First Printed Books

Print in China

• The earliest print technology was developed in China, Japan and Korea.

• By the seventeenth century, as urban culture bloomed in China, the uses of print diversified.

• In the late nineteenth century, western printing techniques and mechanical presses were imported as Western powers established their outposts in China.

• Shanghai became the hub of the new print culture.

Print in Japan

• Around AD 768-770, Buddhist missionaries from China introduced hand-printing technology into Japan.

• The Buddhist Diamond Sutra was the oldest Japanese book which was printed in AD 868.

Print Comes to Europe

• In the 11th century, Chinese paper reached Europe via the silk route.

• In 1295, Marco Polo, a great explorer, returned to Italy from China and brought printing knowledge back with him.

• Italians began producing books with woodblocks, and soon the technology spread to other parts of Europe.

→ As the demand for books increased, booksellers all over Europe began exporting books to many different countries.

• But the production of handwritten manuscripts could not satisfy the ever-increasing demand for books because:
→ Copying was an expensive,
laborious and time-consuming business.
→ Manuscripts were fragile, awkward to handle.

• In the 1430s, Johann Gutenberg invented new printing technology by developing first-known printing press at Strasbourg, Germany.

Gutenberg and the Printing Press

• Gutenberg learned the art of polishing stones, became a master goldsmith, and also acquired the expertise to create lead moulds used for making trinkets.

• Based on this knowledge, Gutenberg adapted existing technology to design his innovation.

• By 1448, Gutenberg perfected the system.
→ The first book he printed was the Bible.

• Between 1450 and 1550, printing presses were set up in most countries of Europe.

The Print Revolution and Its Impact

A New Reading Public

• Access to books created a new culture of reading.

• However, the rates of literacy in most European countries were very low till the twentieth century which was a major hurdle in spreading of this culture.

• So printers began publishing popular ballads and folk tales, and such books would be profusely illustrated with pictures.

Religious Debates and the Fear of Print

• People believed can lead to the fear of the spread of rebellious and irreligious thoughts.

• In 1517, the religious reformer Martin Luther wrote ‘Ninety Five Theses’ criticising many of the practices and rituals of the Roman Catholic Church.
→ This led to a division within the Church and to the beginning of the Protestant Reformation.

The Reading Mania

• By the end of the eighteenth century, in some parts of Europe literacy rates were as high as 60 to 80 percent.

• In England, Penny chapbooks were carried by petty pedlars known as chapmen and sold for a penny.

• In France were the ‘Biliotheque Bleue’ - low priced small books printed on poor quality paper and bound in cheap blue covers.

• Newspapers and journals carried information about wars and trade, as well as news of developments in other places.

Print Culture and the French Revolution

• Print culture created the conditions within which French Revolution occurred.

• Print popularized the ideas of the Enlightenment thinkers.

• Print created a new culture of dialogue and debate.

• By the 1780s, literature mocked the royalty and criticized their morality were large in number.

The Nineteenth Century

Children, Women and Workers

• In 1857, in France, a children’s press, devoted to literature for children alone was set up.

• Women became important as readers as well as writers.

• Penny Magazines were especially meant for women, manuals teaching proper behaviors and housekeeping.

• In the nineteenth century, lending libraries in England became a medium for educating white-collar workers, artisans and lower-middle-class people.

Further Innovations

• By mid 19th Century, Richard M. Hoe perfected the power driven cylindrical press.

• In the late 19th century, offset press was developed that can print up to six colours at a time.

• By the 20th century, electrically operated presses accelerated printing operations.

India and the World of Print

Manuscripts Before the Age of Print

• In India, manuscripts were copied on palm leaves or on handmade paper.

Print Comes to India

• In the mid-sixteenth century, the printing press first came to Goa with Portuguese missionaries.

• By 1674: About 50 books had been printed in Konkani and in Karana languages.

• Cochin, 1579, Catholic priests printed the first Tamil book

• In 1713, Catholic priests printed the first Malayalam book

• By 1710, Dutch Protestant missionaries had printed 32 Tamil texts

• From 1780: James Augustus Hickey began editing the Bengal Gazette, a weekly magazine.

Religious Reform and Public Debates

• From the early nineteenth century, there were intense debates around religious issues.

• Different groups offered a variety of new interpretations of the beliefs of different religions.

• In 1821, Rammohun Roy published the Sambad Kaumudi.

• In 1810, the first printed edition of the Ramcharitmanas of Tulsidas, a 16th century text published in Calcutta.

New Forms of Publication

• The novel, a literary firm which had developed in Europe soon acquired distinctively Indian forms and styles.

• Other new literary forms such as lyrics, short stories, essays about social and political matters also entered the world of reading.

• Painters like Raja Ravi Varma produced visual images for mass circulation.

Women and Print

• Liberal husbands and fathers began educating their womenfolk at home.

• Conservative Hindus believed that a literate girl would be widowed.

• Muslims feared that educated women would be corrupted by reading Urdu romances.

Print and the Poor People

• In the 19th century, very cheap and small books were brought to markets.

• From the late nineteenth century, issues of caste discrimination began to be written about in many printed tracts and essays.

Print and Censorship

• Before 1798, the colonial state under the East India Company was not much concerned about censorship.

• By 1820s, the Calcutta Supreme Court passed certain regulations to control press freedom.

• After the revolt of 1857, the attitude to freedom of the press changed.

• In 1878, the Vernacular Press Act was passed which provided the government with extensive rights to censor reports and editorials in the vernacular press.

→ Despite repressive measures, nationalist newspapers grew in numbers in all parts of India.

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Ch 5 Age of Industrialisation Class 10th Notes| History Social Science

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Ch 5 Age of Industrialisation Class 10th Notes| History Social Science

Before the Industrial Revolution

• Proto-industrialisation was a phase when there was large-scale industrial production for an international market which was not based on factories.

• Proto-industrial system was part of a network of commercial exchanges.

The Coming Up of the Factory

• By the 1730s, the earliest factories in England came up.

• The first symbol of the new era was cotton.
→ A series of inventions in the eighteenth century increased the efficacy of each step of the production process.

• Richard Arkwright created the cotton mill.

The Pace of Industrial Change

How rapid was the process of industrialisation?

• The most dynamic industries in Britain were clearly cotton and metals.

• The new industries could not easily displace traditional industries.

• Technological changes occurred slowly because:
→ The New technology was expensive.
→ The machines often broke down and repair was costly.
→ They were not as effective as their inventors and manufacturers claimed.

Hand Labour and Steam Power

• In Victorian Britain, there was no shortage of human labour.

• Therefore, industrialists did not want to introduce machines which required large capital investment.

• Many seasonal industries were also there who usually preferred hand labour.

• Handmade goods came to symbolize refinement and class

Life of the Workers

• Labours were available in abundance in the market which affected the lives of workers.

• After the busy season was over, workers became jobless.

• In the early nineteenth century, wages increased but the prices of goods also increased.

Industrialisation in the Colonies

The Age of Indian Textiles

• Before the age of machine industries, silk and cotton goods from India dominated the international market in textiles.

• A vibrant sea trade operated through the main pre-colonial ports.

What Happened to Weavers?

• After the East India Company established political power, they tried to eliminate the existing traders and brokers and establish a more direct control over the weaver.

• It appointed a paid servant called the gomastha to supervise weavers, collect supplies, and examine the quality of cloth.
→ Loans were provided for purchasing raw material for production.
→ The produced cloth was to be handed over to the gomastha.

• In many weaving villages there were reports of clashes between weavers and gomasthas because:
→ The new gomasthas were outsiders, with no long-term social link with the village.
→ The price weavers received from the Company was miserably low.

Manchester Comes to India

• As cotton industries developed in England, industrial groups pressurised the government to impose import duties on cotton textiles so that Manchester goods could sell in Britain without competition.

• Also, they persuaded the East India Company to sell British manufactures in Indian markets as well.

• Thus, cotton weavers in India faced two problems at the same time:
→ Their export market collapsed as market overloaded with Manchester imports.
→ Availability of lower cost cotton goods produced by machines.

• By the end of the nineteenth century, factories in India began production, flooding the market with machine-made goods which created a problem of weavers.

Factories Come Up

• In 1854, the first cotton mill in Bombay came up.

• In 1855, first jute mill in Bengal came up.

• By 1862, four cotton mills came up.

• In 1862, another jute mill came up.

• In the 1860s, the Elgin mill was started in Kanpur

• In 1861, the first cotton mill of Ahmadabad was set up.

• In 1874, the first spinning and weaving mill of Madras began production.

The Early Entrepreneurs

• In Bengal, Dwarkanath Tagore made his fortune in the China trade.

• In Bombay, Parsis like Dinshaw Petit and Jamsetjee Nusserwanjee Tata who built huge industrial empires in India.

• After colonial power came in power, Indian businessmen were barred from trading with Europe in manufactured goods.

Where Did the Workers Come From?

• In most industrial regions workers came from the districts around.

• Industrialists usually employed a jobber to get new recruits.

→ He got people from his village, ensured them jobs, helped them settle in the city.

The Peculiarities of Industrial Growth

• European Managing Agencies established tea and coffee plantations, acquiring land at cheap rates from the colonial government.

• By the first decade of the twentieth century, the swadeshi movement promoted Indian industries.

• From 1906, moreover, the export of Indian yarn to China declined since produce from Chinese and Japanese mills flooded the Chinese market.

• During the First World War, British mills busy with war production to meet the needs of the army, Manchester imports into India declined.

• After the war, Manchester could never recapture its old position in the Indian market.

Small-scale Industries Predominate

• Large industries formed only a small segment of the economy and most of them were located in Bengal and Bombay.

• In the twentieth century, handicrafts production and handloom actually expanded.

• By the second decade of the 20th century, weavers used looms with a fly shuttle.

Market for Goods

• New consumers are created is through advertisements.

• Advertisements appear in newspapers, magazines, hoardings, street walls, television screens.

• Advertisements became a vehicle of the nationalist message of Swadeshi.

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CBSE Notes Class 10 Social Science The Making of a Global World

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CBSE Notes Class 10 Social Science The Making of a Global World

Class 10 Social Science The Making of a Global World – Get here the Notes for Class 10 The Making of a Global World. Candidates who are ambitious to qualify the Class 10 with good score can check this article for Notes. This is possible only when you have the best CBSE Class 10 Social Science study material and a smart preparation plan. To assist you with that, we are here with notes. Hope these notes will helps you understand the important topics and remember the key points for exam point of view. Below we provided the Notes of Class 10 Social Science for topic The Making of a Global World.

Class: 10
Subject: Social Science
Topic: The Making of a Global World
Resource: Notes

CBSE Notes Class 10 Social Science The Making of a Global World

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Candidates who are pursuing in Class 10 are advised to revise the notes from this post. With the help of Notes, candidates can plan their Strategy for particular weaker section of the subject and study hard. So, go ahead and check the Important Notes for Class 10 Social Science The Making of a Global Worldr from this article.
Conquest, Disease and Trade

In 16th century after European sailors found a sea route to Asia, they discovered America.
The Indian subcontinent had been known for bustling trade with goods, people, customs and knowledge . It was a crucial point in their trade network.
After the discovery of America, its vast lands and abundant crops and minerals began to transform trade and lives every where.
Precious metals, particularly silver from mines located in Peru and Maxico enhanced Europe’s wealth and financed its trade with Asia.
The Portuguese and Spanish conquest and colonization of America was under way. The most powerful weapon of the Spanish conquerors was not a conventional military weapon but germs of small pax which they carried. America’s original inhabitants had no immunity against such type of diseases

A World Economy Takes Shape

Abolition of the Corn law.
Under pressure from lauded groups the government restricted the import of food grains.
After the carn laws were scrapped, food could be imported into Britain more cheaply than it could be produced in the country.
British farmers were unable to compete with imports. Vast areas of land were left uncultivated.
As food prices fell, consumption in Britain rose.
Faster industrial growth in Britain led to higher incomes and more food imports.

Bretton Woods Institutions

To deal with external surpluses and deficits a conference was held in July 1944 at Bretton woods in New Hampshire U.S.A.
International Mountary fund and world Bank were set up to finance post war reconstruction.
The past war international economic system is known as Bretton woods systems.
This system was based on fixed exchange rates.
IMF and World Bank are referred as Bretton Woods Twins.
U.S has an effective right of veto over key IMF and World Bank.

New International Economic Order – NIEO

Most developing countries did not benefit from the fast growth of Western economies in 1950’s & 60’s.
They organized themselves as a group. The group of 77 or G-77 to demand a new international economic order (NIEO).
It was a system that would give them real control over their natural resources more development assistance, fairer prices for raw materials and better access for their manufactured goods in developed countries markets.

Important Questions
1. Explain how the Global transfer of disease in the pre-modern world helped in the colonialism of the Americas?
2. Why did the British Government had to take the decision to abolish the corn laws?
3. What do you mean by Bretton Woods Agreement? What was its aim?
4. What is referred to as the G-77 countries? In what way can G-77 be seen as a reaction to the activities of bretton Woods Twins?

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Class 10 Social Science History for Notes Nationalism in India:

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Class 10 Social Science History for Notes The Rise of Nationalism in Europe:

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Last Minute Preparation Tips For class 10 Science exam.

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The Central Board of Secondary Education (CBSE) conducts the class 10th science exam in the month of February or March. Students need proper guidance and preparation strategy to score good marks in science. The class 10 science syllabus is really vast. Students should have a proper study plan so that they finish the syllabus by the end of December month and get enough time for practising the previous year’s papers and sample papers. Some students find this subject easier while some find it difficult. So, to help students prepare in a better way for the exam we have provided CBSE class 10 Science preparation tips. These tips will work for all students.

Preparation Tips for Class 10 Science Exam

Students must study through the NCERT Textbook. The book covers the entire syllabus and the question paper is designed from it. So, students must be thorough with all the concepts. They must also solve the exercise questions of the book. Here are a few tips which will help them prepare effectively for the exam.

1) Know the Exam Pattern and Marking Scheme

CBSE class 10 theory science paper is of 80 marks. The question paper is divided into 5 sections. The marks distribution and the number of questions for each section is shown below. To know the detailed question paper design and unit-wise marks distribution students should go through the CBSE Class 10 Science Syllabus.

Sections Name	Marks per Question	Total Questions	No. of words for Answering
A	1	2	1 word or 1 sentence each
B	2	3	30 words each
C	3	10	50 words each
D	5	6	70 words each
E	2	6	Brief answer (Word limit not specified)
Total		27

The above data is provided by analyzing the class 10 science 2019 question paper. It is expected that the same pattern will be followed in 2019-2020 exam. However, there can be some changes in the questions paper pattern.

2) Go through the entire Science Syllabus Once Again

Students must have completed the syllabus along with the classroom. But they need to go through it once again by themselves. This will be a kind of revision for themselves and they get to know on which topic they have to put extra effort. Accordingly, they can formulate an effective study plan and work on those areas. Along with the revision, it will be better if they solve the NCERT textbook questions once again. In case students get stuck somewhere then they can refer the NCERT Solutions of Class 10 Science.

3) Preparation Tips for Class 10 Science Exam

Class 10th Science is one of the major subjects that could help students in shaping up their entire career. Therefore, the students who are willing to continue science in their higher standards are advised to have a thorough conceptual understanding of concepts taught in Physics, Chemistry, and Biology. This will build a strong foundation. Students usually get nervous and stressed as the exam approach. So, here are some important tips that help students in their studies and build confidence in them.

a) Preparation Tips for Class 10 Science – Physics

In physics, conceptual and formula-based questions are mostly asked in the exam. So, students must be thorough with all the important formulas and it should be in their fingertips.
The topic like Newton’s laws of motion and its applications are important from the exam perspective and some of the questions can be expected from it.
Practice numerical on the series and parallel combination of resistances. Most of the time the numerical problems on lens and mirror are also asked.
Practice diagrams like lines of the magnetic field around a solenoid and a bar magnet, electric circuit diagram, AC and DC generator, image formation by lenses and mirrors, the human eye, glass prism, image formation for both defected and correct vision.
Practice previous year question papers and model test papers to get an idea on what types of numerical and theoretical questions are asked from Physics portion.

b) Preparation Tips for Class 10 Science – Chemistry

Chemistry is a high-scoring part and requires lesser time for preparation. Learn the tips involved in balancing chemical equations. Also, memorize the applications of acids, bases, and salts in everyday life.
Every year 2-3 questions are asked form salts and its compounds. So, students must know the common names, preparation, chemical formula, and uses of salts and its compounds.
Focus on carbon compounds and it’s nomenclature containing functional groups.
Make proper notes of all reactions involving the conversion compounds. These revision notes will assist in your last-minute preparations.
Understand the Modern periodic table with electronic configuration and memorize all the elements placed in the 1st and last two groups of the Periodic table.
Speed and accuracy can be acquired through extensive practice of sample papers and in-depth preparation of the subject.

c) Preparation Tips for Class 10 Science – Biology

In biology, the students must practice diagrams like the representation of reflex action, respiratory system, the human brain, different parts of a flower, female and male reproductive organs, etc.
Thoroughly prepare Mendel’s experiments and understand the traits Inheritance.
In Biology, there are complex terminologies that could be memorized by doing regular revisions. It is always good to write and understand those terms to get acquainted with them.
Understand the functions performed by the reproductive organs in humans and the reproduction process in plants.
Biology comprises of several complex diagrams, therefore students must build a habit of drawing a neat and clean diagram while writing the answers. This will also help them in scoring more marks.

4) General Tips to be Followed Before the Exam Day

Students must not touch any new topic before the exam day.
Students should revise from their notes that they have created during preparation.
Be relaxed and cool.
Take proper sleep at night before the exam day.
Students should make sure that they have not skipped any important topic from the syllabus.

5) Tips for Attempting the CBSE Class 10 Science Question Paper

While attempting the paper students must take care of the following things:

Write the answers depending on the marks allocated to it.
Do not get stuck to a particular question. Students must move on if they could not able to find the answer to a particular question.
Keep an eye on the time and try to finish all the entire paper in the allocated time duration.
Draw the diagram wherever required to explain the answer.
Write answers in good handwriting and try to maintain it till the end of the answer sheet.

Most importantly the students are advised to practice at least previous 5 to 6 years’ CBSE class 10 science question papers. It helps the students to understand the exam pattern and enhances their speed, accuracy, and time management skills. Following these techniques will surely ensure excellent performance in the CBSE Class 10 Science Board Exam.

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How Do Organisms Reproduce Class 10 Science Most Important Notes

By Jaitus

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Chapter 8 How Do Organisms Reproduce Notes:

Topics Covered in Chapter 8 How Do Organisms Reproduce:
Do Organisms Create Exact Copies Of Themselves?
The Importance Of Variation
Modes Of Reproduction Used By Single Organisms

Fission
Fragmentation
Regeneration
Budding
Vegetative Propagation

Spore Formation

Sexual Reproduction
Why The Sexual Mode Of Reproduction?
Sexual Reproduction In Flowering Plants
Reproduction In Human Beings
Introduction To The Chapter
Reproduction is a very important biological process for all organisms in the continuity of the generations. There are different types of living species existing on this planet earth. Few are a single-celled organism, some are multicellular organism while few species lack a true nucleus and other cell organelles. Reproduction varies with the species.
What is Reproduction?
Reproduction is the biological process in which every living organisms give rise to their young ones which are identical to their parents. The nucleus of the cell contains DNA which is the hereditary material. DNA replicates and forms new cells causing variations. So, these cells new cells will be similar but may not be identical to the original cell. The variations are useful for the survival of the individual and species over time as well as basis for evolution.
Types of Reproduction
There are two main types of Reproduction.
Asexual Reproduction
It is a type of reproduction by which offspring are produced from a single parent. Here gametes are not formed and the new individual is identical to the parent. It is extremely useful as a means of rapid multiplication and is usually observed in lower organisms. Asexual reproduction can be of various types: Binary fission, Budding, Vegetative reproduction, Regeneration, Fragmentation, Spore formation, and Parthenogenesis.
Sexual Reproduction
It is the process of reproducing their young ones by the involvement of both the parents. Here, gametes are formed and the new individual is genetically similar but not identical to the parents. It is useful to generate more variations in species and is usually observed in higher organisms. All multicellular organisms, including few plant species, animals and humans undergo Sexual Reproduction.
Importance Of Variation

Variation is useful for the survival of species over time
If a population of reproducing organisms were suited for a particular niche and if the niche were drastically altered, the population could be wiped out
But if some variations were to be present in a few individuals in these populations, there would be some chance for them to survive

Modes of Asexual Reproduction
Fission
The parent cell divides into daughter cells
-> Binary fission – 2 cells are formed. Example- Amoeba
CBSE notes Class 10 Chapter 8 image - 1

-> Multiple fission – many cells are formed. Example – Plasmodium
CBSE notes Class 10 Chapter 8 image - 2

Fragmentation
The organism breaks-up into smaller pieces upon maturation, each piece develops into a new individual. Example – Spirogyra
CBSE notes Class 10 Chapter 8 image - 3

Regeneration
If an organism is somehow cut or broken into many pieces, each piece grows into a complete organism. Example – Hydra, Planaria
CBSE notes Class 10 Chapter 8 image - 4

Budding
A bud is formed which develops into tiny individual. It detaches from parent body upon maturation and develops into a new individual. Example – Hydra

Vegetative Propagation
In many plants, new plants develop from vegetative parts such as
By roots – Example – Dahlias, Sweet potato
By stem – Example – Potato, Ginger
By leaves – Example – Bryophyllum (leaf notches bear buds which develop into plants)
CBSE notes Class 10 Chapter 8 image - 6

Artificial Methods In Vegetative Propagation

Grafting – Example – Mango
Cutting – Example – Rose
Layering – Example – Jasmine
Tissue culture – Example – New plants are grown using growing tips of a plant

These growing cells are kept in a culture medium leads to the formation of callus. Callus is then transferred to the hormone medium which causes growth and differentiation. Example – Ornamental plants, orchid
Benefits of Tissue Culture

We can grow plants like Banana, Rose, Jasmine etc that have lost the capacity to produce seeds
New plants are genetically similar to parents
Helps in growing seedless fruits

Spore Formation
Spores are small bulb like structures which are covered by thick walls. Under favourable conditions, they germinate and produce new organism. Example – Rhizopus
CBSE notes Class 10 Chapter 8 image - 7

Sexual Reproduction
When reproduction takes place as a result of the fusion of male and female gametes is called sexual reproduction. The fusion of gametes is called fertilization which results in variation.
Sexual Reproduction In Plants

Flowers are the reproductive organs of plants
A typical flower consists of four main whorls namely sepals, petals, stamen and pistil

Types Of Flowers
Bisexual Flower – Both male and female reproductive parts are present. Example – Hibiscus, mustard
Unisexual Flower – Either male or female reproductive part is present. Example – Watermelon, Papaya
Structure Of Flower

Process of Seed Formation

Pollen grains, produced in the anther, are transferred to the stigma of the same flower (self-pollination) or stigma of another flower (cross-pollination) through agents like air, water or animals
Pollen grains germinate and form pollen tubes which pass through the style to reach up to the ovules present in the ovary
The fusion of male and female gametes is called fertilization. The zygote is produced inside the ovary.
The zygote divides to form the embryo. Ovule develops a thick coat and changes into seed gradually
Ovary changes into fruit and other parts of flower fall off

Germination of pollen on stigma
The seed germinates to form a plant under suitable conditions such as air, moisture etc

Reproduction in Human Beings

Humans use the sexual mode of reproduction.
Sexual maturation – the period of life when production of germ cells i.e., ova (female) and sperm (male) start in the body. This period of sexual maturation is called puberty.

Changes at Puberty

Common in male and female

– Thick hair growth in armpits
– Skin becomes oily, may result in pimples

In Girls

– Breast size begins to increase
– Girls begin to menstruate

In Boys

– Thick hair growth on the face
– Voice begins to crack
These changes signal that sexual maturity is taking place
Male Reproductive System
(i) Testes

A pair of testes are located inside scrotum which is present outside the abdominal cavity
Scrotum has a relatively lower temperature needed for the production of sperms
Male germ cells i.e., sperms are formed here
Testes release male sex hormone (testosterone)

Function of Testes

Regulates production of sperms
Brings changes at puberty

(ii) Vas Deferens

It passes sperm from the testes to the urethra

(iii) Urethra

It is a common passage for both sperm and urine. Its outer covering is called penis.

(iv) Associated glands

Seminal vesicles and prostate gland add their secretion to the sperms. This fluid provides nourishment to sperms and makes their transport easy
Sperm along with the secretion of glands form semen

CBSE notes Class 10 Chapter 8 image - 11

Female Reproductive System
(i) Ovary

A pair of ovaries are located on both sides of the abdomen
Female germ cells i.e., eggs are produced here
At the time of the birth of a girl, thousands of immature eggs are present in the ovary
At the onset of puberty, some of these eggs start maturing
One egg is produced every month by one of the ovaries

(ii) Oviduct or Fallopian Tube

Receives the egg produced by the ovary and transfers it to the uterus
Fertilization i.e., a fusion of male and female gametes takes place here

(iii) Uterus

It is a bag-like structure where development of the baby takes place
Uterus opens into the vagina through cervix

Fertilization of Egg

When egg is fertilized

– The fertilized egg called zygote is planted in the uterus and develops into an embryo
– The embryo gets nutrition from the mother’s blood with the help of a special tissue called placenta. It provides a large surface area for the exchange of glucose, oxygen and waste material
– the time period from fertilization upto the birth of the baby is called gestation period. It is about 9 months.

When egg is not fertilized

– The uterus prepares itself every month to receive fertilized egg
– The lining of the uterus becomes thick and spongy, required to support the embryo
– When fertilization has not taken place, this lining is not needed any longer
– This lining breaks and comes out through vagina as blood and mucus
– This cycle takes around 28 days every month and called menstruation
Reproductive Health
Reproductive health means a total well-being in all aspects of reproduction i.e., physical, social, emotional and behavioral.
-> Sexually Transmitted Diseases (STDs)

Many diseases can be sexually transmitted such as

– Bacterial: Gonorrhoea and Syphilis
– Viral: Warts and HIV-AIDS

Use of condoms prevents these infections to some extent
Contraception – It is the avoidance of pregnancy, can be achieved by preventing the fertilization of ova

-> Methods of Contraception
(i) Physical barrier

To prevent union of egg and sperm
Use of condoms, cervical caps and diaphragm

(ii) Chemical methods

Use of oral pills
These changes hormonal balance of body so that eggs are not released
May have side effects

(iii) Intrauterine contraceptive device (IUCD)

Copper-T or loop is placed in uterus to prevent pregnancy

(iv) Surgical methods

In males, the Vas deferens is blocked to prevent sperm transfer called vasectomy
In females, the fallopian tube is blocked to prevent egg transfer called tubectomy

Female Foeticide

The practice of killing a female child inside the womb is called female foeticide
For a healthy society, a balanced sex ratio is needed that can be achieved by educating people to avoid malpractices like female foeticide and prenatal sex determination
Prenatal sex determination is a legal offence in our country so as to maintain a balanced sex ratio

Few Important Questions