#9th class

[mbacademy]

Why choose MB Academy for tuition in Mansarovar, Jaipur.

6 Reasons why you can not miss out on MB Academy.

1. Regular Test

2. Small batch sizes

3. Subject by teacher

4. Doubt Solving classes

5. Experience Faculty

6. Comprehensive Curriculum

therefor MB Academy is the trusted/best tuition center in Mansarovar, Jaipur. Book your appointment Now 👇👇👇-

[vavaclasses]

Atoms and Molecules Class 9 Science: Chapter-3 NCERT

Introduction:

In the realm of science, the study of atoms and molecules serves as the fundamental building block for understanding the nature of matter. Class 9 science introduces students to this fascinating world, unravelling the mysteries that lie within the microscopic realm. Let's delve into the basic concepts of atoms and molecules and explore how they form the basis of chemistry.

Atoms - The Building Blocks of Matter: At the heart of all matter, from the air we breathe to the food we eat, lies the atom. An atom is the smallest unit of an element that retains the chemical properties of that element. The concept of atoms dates back to ancient Greece, where philosophers such as Democritus first proposed the idea that matter is composed of indivisible particles.

Structure of an Atom: As class 9 science students, it's crucial to understand the structure of an atom. Atoms consist of three subatomic particles: protons, neutrons, and electrons. Protons carry a positive charge, neutrons have no charge, and electrons carry a negative charge. The protons and neutrons reside in the nucleus at the centre of the atom, while electrons orbit the nucleus in energy levels or shells.

Atomic Number and Mass Number: Every element is characterized by its unique atomic number, representing the number of protons in its nucleus. The mass number, on the other hand, is the sum of protons and neutrons in an atom. Understanding these properties is essential for distinguishing one element from another.

Molecules - Combining Atoms: Molecules are formed when atoms combine through chemical bonds. Atoms can share, gain, or lose electrons to achieve a stable electron configuration, forming compounds with unique properties. The sharing of electrons leads to covalent bonds, while the transfer of electrons results in ionic bonds. Water (H₂O) and methane (CH₄) are examples of common molecules.

Chemical Formulas: Class 9 science explores the language of chemistry through chemical formulas. These notations represent the types and numbers of atoms present in a molecule or compound. For instance, the chemical formula for water is H₂O, indicating two hydrogen atoms and one oxygen atom in each molecule.

Laws of Chemical Combination: Students delve into the laws governing chemical combinations, such as the Law of Conservation of Mass and the Law of Definite Proportions. These laws provide a foundation for understanding the quantitative aspects of chemical reactions and the fixed ratios in which elements combine to form compounds. Some- Examples: Certainly! Here's a brief overview of the solutions for Class 9 Science Chapter 3 - Atoms and Molecules, based on the NCERT (National Council of Educational Research and Training) curriculum:

NCERT Solutions for Class 9 Science Chapter 3 - Atoms and Molecules Question 1: In a reaction, 5.3 g of sodium carbonate reacted with 6 g of acetic acid. The products were 2.2 g of carbon dioxide, 0.9 g water, and 8.2 g of sodium acetate. Show that these observations are in agreement with the law of conservation of mass.

Solution: To verify the law of conservation of mass, we need to compare the total mass of reactants with the total mass of products.

Mass of sodium carbonate (Na₂CO₃) = 5.3 g Mass of acetic acid (CH₃COOH) = 6 g

Total mass of reactants = 5.3 g + 6 g = 11.3 g

Mass of carbon dioxide (CO₂) + Mass of water (H₂O) + Mass of sodium acetate (CH₃COONa) = 2.2 g + 0.9 g + 8.2 g = 11.3 g

Since the total mass of products is equal to the total mass of reactants, the observations are in agreement with the law of conservation of mass.

Question 2: Hydrogen and oxygen combine in the ratio of 1:8 by mass to form water. What mass of oxygen gas would be required to react completely with 3 g of hydrogen gas?

Solution: The given ratio is 1:8 for hydrogen and oxygen, respectively. Mass of hydrogen (H₂) = 3 g

According to the ratio, the mass of oxygen (O₂) required = 8 * Mass of hydrogen = 8 * 3 g = 24 g

Therefore, 24 g of oxygen gas would be required to react completely with 3 g of hydrogen gas. Question 3: What is the mass of one molecule of water?

Solution: The molecular formula of water is H₂O.

The molar mass of hydrogen (H) = 1 g/mol The molar mass of oxygen (O) = 16 g/mol

The molar mass of water (H₂O) = 2 * Molar mass of hydrogen + Molar mass of oxygen = (2 * 1 g/mol) + 16 g/mol = 18 g/mol

One mole of water contains Avogadro's number of molecules (6.022 × 10²³). Therefore, the mass of one molecule of water = Molar mass of water / Avogadro's number = 18 g/mol / (6.022 × 10²³ mol⁻¹)

This value is extremely small, indicating the tiny mass of a single water molecule. Question 4: If one mole of carbon atoms weighs 12 g, what is the mass (in grams) of 1 atom of carbon?

Solution: Given that one mole of carbon atoms weighs 12 g, which is equal to the molar mass of carbon.

The molar mass of carbon (C) = 12 g/mol

Now, to find the mass of 1 atom of carbon, divide the molar mass by Avogadro's number (6.022 × 10²³ mol⁻¹):

Mass of 1 atom of carbon = Molar mass of carbon / Avogadro's number = 12 g/mol / (6.022 × 10²³ mol⁻¹)

This value represents the mass of a single carbon atom.

These are just a few examples of the solutions found in Chapter 3 of Class 9 Science - Atoms and Molecules. It's essential to practice additional problems and exercises to strengthen your understanding of the concepts.

Conclusion: As students explore the world of atoms and molecules in class 9 science, they embark on a journey that unlocks the secrets of the microscopic realm. This knowledge not only forms the basis for understanding chemical reactions and properties but also lays the groundwork for advanced studies in chemistry. Embracing the wonder of the microscopic world, students gain valuable insights into the nature of matter that surrounds us every day.

[arfan039]

Physics 301 Circuit Theory - Virtual University

Physics 301 Circuit Theory Assignement is for the Students of Virutual University of Pakistan. This assignment is about the equivalent resistance Rab of given circuit. While calculation, we also described the calculation methods in this assignment. So that the students can get maximum marks. The circuit diagram of each step is also drawn to make it easy to understand the concept of the equivalent…

[nojaloart]

totally normal nona

commission me!! so i can go watch a play

[marlenacantswim]

my cringefail autistic babygirls nine and ten in the style of "doodles i'd do during class back when they passed out actual physical worksheets"

turns out if you set your procreate pencil to 60% opacity on accident, the graphite effect becomes a lot more believable. who knew!

[Image ID: A digital drawing of the busts of the Christopher Eccleston Doctor and the first David Tennant Doctor in profile, facing right and left respectfully. they are offset vertically, and the style mimics that of a traditional graphite pencil on computer paper; the background sports slight texturing to reinforce this. both doctors are wearing their traditional outfits. each has text written next to them, saying 'nine, last of the Time Lords, the one who loved' and 'the one love bore, Time Lord victorious, ten' respectively. / .End ID]

[class1akids]

9th anniversary color spread (better quality)

Some thoughts:

I like that even though everyone is in uniforms, they all have unique combinations

Bakugou and Uraraka wear 9 and Deku is showing it

All Might facing away with green-orange cape - perhaps foreshadowing some OFA shenanigans with Bakugou

Jirou's lost earlobe is still covered

Sero in glasses? Hmmmm...

Hagakure being visible could point to quirk awakening

Shoji without mask for the first time

Shouto's fluffy hair and cute smile and piano fingers - it's the happiest he ever looked on an anniversary art

back to the origins with Class A + Aizawa + All Might which is what I expected. Maybe the Giga cover will have the villain counterparts, considering they are wearing the "Smash exhibition Toga uniform", so I could imagine villains in UA uniform or something similar if this art was to be reused there.

It has again the interlinked arms design - but this time Bakugou is not touching anyone and neither does All Might.

[hkartincolor]

Chapter 394 - 9th anniversary color spread

[ramayantika]

9th grade me thought I wasn't pretty because of my height, slight acne and thicker thighs

LOL This samridhi is screaming okay. Nobody needs validation by anyone or something.

You are an amazing person, filled with so many wonderful things, love indulging in the things you love and are talented in so many things. There are things you know, people who love you and admire you so much

AND YOU ALL ARE FUCKING BEAUTIFUL OKAY DON'T LET ANYONE TAKE THAT FROM YOU

[glennmillerorchestra]

this is the most important piece of writing in the world to me. (from the house on mango street by sandra cisneros)

[salvadorbonaparte]

If Oppenheimer had come out a decade ago I would have been soooo annoying about it. I definitely would have studied physics.

[mhabirthdays]

Happy Birthday

Itsuka Kendo (Battle Fist) – September 9th

[cowcat44]

The 9th anniversary full color page (higher quality)

Baby come back

[painsandconfusion]

Remembering that time I researched for and wrote a 26 page law school research paper in 33 hours and got an A- in one of the most intensely graded writing-focused law schools in the country. While still in surgery recovery.

How the fuck did I do that

Where did my brain go since then

When do I get her back

Can I write novels like that please?

Please?

I want the writing juice back

Give it backkkkkkk

[73647e]

me resisting the urge to open ao3 and read anderperry fanfiction

[class1akids]

9 years - 9 color spreads

[allgremlinart]

people acting like fandom pressuring creators too much for fanservice is some new thing created by the internet is so funny to me cus like. girl they did that shit to Charles Dickens. legiterally.