Important questions of Science (SEE2076)

1. Describe the mechanism of formation and depletion of the ozone layer.

I. Ozone layer formation

Ozone (O3) is a pale bluish non-toxic gas formed by the photolytic dissociation of molecular oxygen and combination of nascent oxygen with the molecular oxygen.

a. O2→O+O

b. O2+O→O3 (ozone)

In the first step, the molecular oxygen is dissociated into two atomic or nascent oxygen (O) oxygen due to UV rays. The nascent oxygen is very reactive and in turn, gets combined with molecular oxygen to give ozone (O3). Actually, the ozone molecules are formed on the surface of the earth and they rise up in the upper level of the stratosphere to form an umbrella-like protective layer now called the ozone layer.

II. Ozone layer depletion

Formation of the hole on the ozone layer or thinning of the ozone layer is called the ozone layer depletion. The ozone layer is depleted by chlorofluorocarbon (CFC) and oxides of nitrogen.

a. By Chlorofluorocarbon (CFCl3)

First of all the chlorofluorocarbon undergoes the photolytic dissociation in the presence of the UV rays to give nascent chlorine (Cl) and the nascent chlorine is responsible for the ozone layer depletion.

i. CFCl3→CFCl2+Cl

ii. O3+Cl→ClO+O2

In the first step, the chlorofluorocarbon such as trichloro fluorocarbon (CFCl3) is dissociated into dichlorofluoro carbon (CFCl2) and nascent chlorine (Cl) due to the photolytic effect of UV rays. In the second step, the nascent chlorine attacks the ozone molecule (O3) and dissociates into oxychloride (ClO) and molecular oxygen (O2) thus depleting the ozone layer.

Moreover, the oxychloride (ClO) is further dissociated to give nascent chlorine to destroy more ozone thus leading the reaction in a never-ending chain process. One molecule of CFC destroys about 100,000 of the ozone molecules.

b. by the oxides of nitrogen

The nitric oxides released from the nitrogenous fertilizers and supersonic jet planes are responsible for depleting the ozone layer by reducing ozone into molecular oxygen.

i. NO+O3→NO2+O2

ii. 2NO2+O3→N2O3+2O2

First of all, nitric oxide (NO) combines with ozone (O3) and gives nitrogen dioxide (NO2) and molecular oxygen (O2) and the nitrogen dioxide again reacts with ozone to give molecular oxygen in the same way thus repeating the reaction in multiple times. Thus, oxides of the nitrogen are responsible for the ozone layer depletion.

2. Explain the process of making alkali/ base/ antacid from a magnesium ribbon.

In the first step, the magnesium ribbon is burnt with the air (O2) to get magnesium oxide (MgO).

2Mg+O2→2MgO

In the second step, the magnesium oxide is treated with water to get magnesium hydroxide [Mg (OH)2] which is alkali and acts as the antacid to reduce the hyperacidity.

MgO+H2O→Mg (OH)2

3. How does the fire extinguisher work?

Fire extinguisher consists of two chemicals namely saturated sodium bicarbonate (NaHCO3) and concentrated sulphuric acid (H2SO4). At the time of use, the fire extinguisher is inclined or inverted and shaked or dropped on the floor to get mixed above mentioned two chemicals.

When saturated sodium bicarbonate and concentrated sulphuric acid react to each other it gives sodium sulphate, water and carbon dioxide. A large amount of carbon dioxide is sprayed out in very high pressure to extinguish the burning flame.

2NaHCO3+H2SO4 (conc.) →Na2SO4+2H2O+2CO2

The carbon dioxide is very ideal to extinguish fire because it is neither combustible nor the supporter of the combustion. Also, it is heavier than air and the carbondioxide displaces the oxygen coming in contact of flame and covers the flame just like a blanket. Thus, carbon dioxide acts as the fire extinguisher.

4. Explain the naming codes of hydrocarbons according to IUPAC.

International union of pure and applied chemistry (IUPAC) is the common organization of global chemists. This organization has produced a number of codes regarding the nomenclature of the hydrocarbons. The major are as follows:

a. The naming of the hydrocarbon is associated with the specific prefix on the basis of a number of carbon atom present. For instance:

i. 1 carbon atom: Meth

ii. 2 carbon atoms: Eth

iii. 3 carbon atoms: Prop

iv. 4 carbon atoms: But

v. 5 carbon atoms: Pent

vi. 6 carbon atoms: Hex

vii. 7 carbon atoms: Hept

viii. 8 carbon atoms: Oct

ix. 9 carbon atoms: Non

x. 10 carbon atoms: Dec

b. A saturated hydrocarbon series having the carbon carbon single bond (C-C) has got the suffix-ane. So that, the hydrocarbons are named as:

i. Meth+ane=Methane

ii. Eth+ane= Ethane

iii. Prop+ane= Propane

And, Butane, pentane, Hexane, Heptane, Octane , Nonane , Decane, etc.

c. An unsaturated hydrocarbon series having the carbon-carbon double bonds (C=C) has got the suffix-ene. So that, the hydrocarbons are named as:

i. Eth+ene=Ethene

ii. Prop+ene= Propene

Similarly, Butene, pentene, Hexene, Heptene, Octene , Nonene , Decene, etc.

d. An unsaturated hydrocarbon series having the carbon carbon triple bonds (C≡C) has got the suffix- yne. So that, the hydrocarbons are named as:

i. Eth+yne=Ethyne

ii. Prop+yne= Propyne

Similarly, Butyne, pentyne, Hexyne, Heptyne, Octyne , Nonyne , Decyne, etc.

5. Define neutralization reaction? Wite any 2 examples of such reaction. Also, mention any 4 applications of acid base reaction.

When acid and base react each other then both acids and base lose their properties and form two neutral substances namely salt and water. Such chemical reaction is called neutralization reaction.

Examples:

Acid + Base → Salt + Water

i. HCl+NaOH→NaCl+H2O

ii. H2SO4+2KOH→K2SO4+2H2O

There a number of applications of acid base reactions. Any 4 of them are given as follows:

a. Farmers use the lime (base) to treat the acidity of the soil.

b. Human beings use antacids such as magnesium hydroxide and aluminum hydroxide (base) to treat hyperacidity.

c. Honey bees and ants inject formic acid when they sting which can be treated by washing hand with soap (base)

d. Excessive sourness of the food and fruits can be reduced by using baking soda i.e. sodium bicarbonate (base)

6. Define isomers and isomerism. Write the possible isomers of butane and pentane. Also, draw their structural formula.

The organic compounds having the same molecular formula but different structural formula(e) are called isomers.

The phenomenon of having a number of isomers of a compound is called isomerism.

The possible isomers of butane are:

a. n-butane

b. iso-butane

The possible isomers of pentane are:

a. n-pentane

b. iso-pentane

c. neo-pentane

Home work

7. What do you mean by chemical reaction? Write the types of chemical reaction, their definitions and one example of each.

8. What happens when carbon dioxide is passed to thee lime water for long time? Write with balanced chemical equations.

9. We can not use dil sulphuric acid instead of dil hydrochloric acid for the lab preparation of carbondioxide, why?

10. What happens when iron is mixed to the coppersulphate solution?

11. Water acts as both acid and base (amphoteric) liquid, why/how?

12. What do you mean by metallurgy? Describe the process involved in the metallurgy in brief.

Really Cool and Useful Websites for Kids

Younger children will love everything about the online home. They can choose from hundreds of the show's video clips and play games that help them learn letters, animal sounds, rhymes, colours, and more

Scholastic

Scholastic is one of the more different and advances educational websites for kids. This site by  the publishers of the educational books contains activities broken up by grades. The materials are geared from Pre-K learners to seniors in high school.

PBS Kids

Each of the educational shows your child watches on PBS has its own learning section through PBSKids.org. Try sing-a-long songs, sorting and counting games, watch videos, and more.

CoolMath

CoolMath.com calls itself "an amazing park of math and more." Children can play online mathematical games that help them with addition, subtraction, multiplication, division, decimals, money and more. CoolMath is designed toward ages 13 + . The sister site CoolMath4Kids.com is appropriate for ages 3 up to 12. CoolMath-Games.com holds math games for preschoolers.

National Geographic Kids

Watch animal on cameras, learn interesting activities about animals, see and share photos of nature, learn and know about different countries and try new science experiments on Kids.NationalGeographic.com. These activities don't even begin to scratch the surface of the National Geographic Kids website. There's also a interesting  "Little Kids" section for the younger explorers in your home.

The KIDZ Page

TheKidzPage.com holds more than 5,000 pages of learning games and kids activities. Online colouring pages, word games, jigsaw puzzles and word puzzle are just a few sections of this massive site. Each holiday has its own activities and games to enjoy with your child

Fun Brain

One visit to Fun Brain and you'll love to bookmark it for your kids. Math, reading, online books , fun and learning games are just a few sections. Fun  brain is designed to preschoolers up to 8th graders.

Exploratorium

 San Francisco's Exploratorium at the Palace of Fine Arts showcases is a website full of great science resources. It teaches kids about science and art in different ways. The departments let kids tinker with gadgets, go below the sea, rocket into the galaxy and also learn about the science of gardening, animals, and cells, to name a few.

BBC History for Kids

Games, quizzes and fact sheets take kids to the new amazing world. Kids can enjoy adventure of  ancient history, world history and histories of specific countries on the BBC History for Kids website.

The 6 best preschool apps for learning and fun

Your home is the first Institute that the child figures out the learning. But most of the parents find difficult when it’s the time to occupy their children when the school is out. Most the parents hang their children with their smartphones and tablets to get rid of their child.  Do you think the apps are enough good for your child? Here we have listed the best apps that are good for preschoolers. Just grab your mobile and download the best apps for kids which are enriched with fun, educational, and many more.
Kids Academy: It has over 5000 preschool learning activities. The app includes educational games and videos, songs, interactive and printable worksheets, puzzles and flashcards. The app covers the key subject areas of Math, Science, Reading, Language Arts and Social Studies.
The parents can easily track the progress of children. You can identify and develop the child’s talent and work on the topics that need improvement.

The app is available on iPhone, iPad and Android.

Preschool & Kindergarten Games

Preschool & Kindergarten Games is an interactive educational app that suits for the ages of 4+. The popular apps encourage the children to learn letters, their spellings, maths with 24 educational games with child-based learning curriculum including shapes, colours, counting, puzzles, spelling, vowels and consonants and so much more. For encouraging the learning the apps reward stickers for playing and learning.

Preschool & Kindergarten Games is available on iPad, iPhone and Android devices.

Zoolingo - Preschool & Kindergarten Games

the beautifully drawn and brightly coloured graphics attract the child to use the app. The fun and educational materials help young children consolidate and develop their learning.
You can get unlimited access to tons of educational games including maths, English, social science, much more, all in one app!
The app is available on iPhone, iPad, and Android

Khan Academy Kids, Free  :

It includes a huge database of games and activities pulling from Head Start Early Learning. This is also one of the best apps among children.

Narrator AR

It’s an amazing app that supports pre-school writing in a fun and inspiring way. The app is suitable for ages 3 to 5. It encourages children to write words and letters with a pen and paper whilst linking this to an exciting experience. With this ad-free and offline app, the children can have a fun experience.

LetterSchool - learn to write letters and numbers: The app LetterSchool is a beautifully and graphically designed for handwriting. The app teaches the children how to write letters (both upper and lower case) and numbers (from 1 to 10) in an animated and fun way. For the best learning this app must be installed in your mobile.  The app is available on iPhone, iPad and Android

6 Early Literacy Skills Your Child Needs To Know & Simple Ways to Develop Them!

As concerned parents, we love nothing more than or for our children. In this mean time to live out their full potential as they go about their lives. so we are always careful on the lookout for ways to help them along on this journey. You can give/start your child a little head-start with some simple and easy pre-literacy skills!

A child’s early literacy means to his/her understanding of reading and writing prior to knowing how to read or write. It may Sound funny, but it’s a simple way of expressing. Proficiency in early literacy is a good indicator of your child’s aptitude for language. Think of these skills are the foundation of your child’s first steps into literacy.

#1. Print Motivation

This skill helps and involves your child in demonstrating an interest in books. This is critical to him/her development as a reader. Reading begins with motivation and curiosity. Learning to read isn’t going to be easy, but if he/she has positive conditioning about print, she’s likely to develop the interest to read independently.



Develop This Skill:

•     Reading books he/she likes
•     Make reading fun!
•     Pique his/her interest by modulating your tone according to the story

#2. Print Awareness

Have you noticed your child pick up a book and try to place her finger of the sentences to pretend to read it? She’s displaying print awareness! This skill involves noticing print everywhere and anywhere. It also involves knowing how to handle a book. Your child must be aware of words before leaning to decipher them. She must demonstrate some understanding of the cover of a book, way to read a book, etc.

Develop This Skill:

    Reading board books that your child can handle on her own; her turn the pages as you read together.
    Pointing to the words as you read.
    Talking about print even when you are not reading together. Look for letters and words on signs, labels, and lists.



#3. Letter Knowledge

This skill simply involves understanding that letters are different from each other, have different names and sounds and can recognize them anywhere. Your child’s understanding of letter knowledge is critical to her learning to read. To be a good reader, your child must understand that a word is made of smaller, individual letters with different sounds.  If she has difficulty grasping sounds of letters, you might need to introduce her to phonics, etc.

Develop This Skill:

    Looking at and talking about different shapes (letters are based on shapes)
    Playing “same and different” type games
    Looking at “I Spy” type books
    Talking about and drawing the letters of a child's own name



#4.    Vocabulary

A rich wealth of spoken vocabulary can make learning to read easier. It's much easier to read a word when it's a word you already know. Children with bigger vocabularies have an easier time when they start to read because it's much easier for them to make sense of what they're sounding out.

Develop this skill:

•     Encourage children to learn their native or home language first
•     Carry on lots of conversations with children.
•     Explain the meanings of new words.

#5.    Phonological Awareness

This skill involves the ability to break apart a word into smaller sounds. Children who can hear how words "come apart" into separate sounds will be more successful at "sounding out" words when they start to read.

Develop this skill:

    Sing songs, most break words up into one syllable per note. Reading works with syllables also.
    Recite rhymes; rhymes depend upon ending sounds.
    Play with tongue twisters.
    Pick a sound for the day. Notice it at the beginning of words and at the end of words.



#6.    Narrative Skills

Does your child like describing things, events and sharing stories? This is important as it’s another pre-literacy skill!  When she can describe something or retell stories, it shows that she’s comprehending what she’s reading. Understanding what she’s reading is crucial to helping her stay motivated to keep reading.

Develop this skill:

•     Ask open-ended questions that encourage conversations rather than yes/no or right/wrong answers.
•     Talk about your day and its series of events.
•     Mix up the events in a story; make it silly!
•     Guess what comes next—or come up with a different ending.
•     Read stories without words; they really help focus on this skill.
•     Name objects, feelings, and events.

Early literacy skills make your child a better reader.

Is it possible to impart early literacy skills through play? Learn this and more at SEED Institute’s workshop for parents in April titled “Using Multisensory Games and Activities to Build Early Literacy Skills.” Facilitated by Sylvia Foo who has over 2 decades of experience as a Literacy and English Language Specialist. In this workshop, she helps you to understand are early literacy skills your child requires and ways you can impart them in fun, multisensory ways.