Notes, abstracts, papers, exams and problems of Chemistry

Questions

Answers

Why do you use distilled water in your experiments?

Because distilled water has all its impurities removed through distillation.

What is the formula for converting oC to Fahrenheit( F)?

(oC x 1.8) + 32

Formula for converting oF into Celsius

 (oF - 32)  1.8

Formula for converting oC to Kelvin(K)

K = oC + 273.15

Name all the volumetric apparatus used in the lab

Beaker, measuring cylinder, Burette, Pipet, and volumetric flask. (See the attachment)

A student got the following results in his experiment: 14.9g, 14.19g, 14.88g, 14.92g, but the actual weight is 20.90g. How accurate are the student results. And how precise are the results.

The student results are not accurate but precise. Has the precision of  0.05g

Sketch 2 pieces of glassware:

Kinetic Energy and the Nature of Matter

• Kinetic Energy: The energy an object possesses due to its motion.
• Kinetic Theory: States that all matter is composed of tiny particles in constant motion.

Pressure and Its Measurement

• Gas Pressure: Results from the force exerted by a gas per unit surface area of an object.
• Vacuum: An empty space devoid of particles and pressure.
• Atmospheric Pressure: Arises from the collisions of atoms and molecules in the air with objects.
• Barometer: A device used to measure atmospheric pressure.
• Pascal (Pa): The SI unit of pressure.
• Standard Atmosphere (atm): The pressure required to support 760 mm of mercury in a mercury barometer at 25ºC.

Phase Transitions and States of Matter

• Vaporization: The conversion of a liquid to a gas

How Solutions are Formed

The particles that make up a solution are in constant movement: they move faster as they go from solid state to liquid state. This happens until we obtain a homogeneous system where all its parts have the same properties. This movement is responsible for them mixing together.

Types of Solutions

Gaseous Solutions

The most important is air.

Liquid Solutions

The most important liquid solutions are those that involve water. When the forces with which the water molecules attract the molecules of the solid are greater than the forces acting between them, the particles separate and form the solution.

Solid Solutions

Alloys are mixtures of metals obtained by mixing together the melted components.

Diluted Solution: Amount of solute small... Continue reading "Formation of Solutions: Types and Properties" »

Indian Classical Music Quiz

a) How many kinds of ‘Graha’ are there?

1. 1
2. 2
3. 3
4. 4

(अ). ग्रह के ककतने प्रकार है (i) 1 (ii) 2 (iii) 3 (iv) 4

b) Minimum avartan of ‘Paran’ are:-

1. 4
2. 5
3. 2
4. 1

(ब) ऩरण कम से कम ककतने आवतनय का होता है (i) 4 (ii) 5 (iii) 2 (iv) 1

c) 4 5 6 indicates the Tala Dha Tu Na 0

1. Dadra
2. Keharwa
3. Rupak
4. Dhamar

स)) 4 5 6 ककस ताऱ का दशायता है्- धा तू ना 0 (i) दादरा (ii) कहरवा (iii) रुऩक (iv) धमार

d) How many kinds of ‘Jatti’ are there?

1. 3
2. 4
3. 5
4. 6

(द) िानत के ककतने प्रकार हैं? (i) 3 (ii) 4 (iii) 5 (iv) 6

e) Laggi is used in :-

1. Khyal
2. Dhrupad
3. Bhajan
4. Dhamar

य)... Continue reading "Indian Classical Music Quiz: Graha, Paran, Tala, and Jatti" »

Nucleus: The Center of an Atom

The nucleus is located at the center of an atom. It is very small and has a positive electrical charge due to the protons. The nucleus contains particles called protons and neutrons, which make up nearly all of the atom's mass.

Electron Cloud: The External Area of an Atom

The electron cloud surrounds the nucleus and is longer than the nucleus. It has an equal but negative electrical charge compared to the protons. The electron cloud contains particles called electrons, and their mass is negligible compared to the protons and neutrons.

Historical Development of Atomic Structure

In the 5th century, ancient Greeks proposed the concept of the atom. In 1808, Dalton discovered the existence of protons and electrons. In 1904,... Continue reading "Atomic Structure and Chemical Reactions: A Comprehensive Overview" »

Crystalline Solids

Crystal Lattice

The main characteristic of crystalline solids is a regular and repeating pattern of constituent particles. A crystal lattice is a three-dimensional arrangement of points in space, representing the arrangement of these particles.

Unit Cells

Unit cells are the smallest repeating units in a crystal lattice. They are broadly divided into two categories:

• Primitive Unit Cells: Constituent particles are present only at the corners.
• Centred Unit Cells: Contain particles at positions other than corners, in addition to those at the corners. There are three types of centered unit cells:
  • Body-Centred Unit Cells: Contain one particle at the body-center, besides those at the corners.
  • Face-Centred Unit Cells: Contain one particle

Water: Essential Properties for Life

Polarity and Hydrogen Bonds in Water Molecules

• A water molecule comprises an oxygen atom covalently bonded to two hydrogen atoms.
• Oxygen is more electronegative than hydrogen, leading to an unequal sharing of electrons.
• This creates a polar covalent bond, with hydrogen having a partial positive charge and oxygen having a partial negative charge.
• The bent shape of water molecules results in a positive charge concentration on one side and a negative charge on the opposite side.
• The partial positive charge is attracted to the partial negative charge, creating an intermolecular attraction between water molecules called a hydrogen bond.
• Hydrogen bonds are the strongest intermolecular forces, but they are still considered

Saturated Solution

Contains the maximum amount of solute for a given quantity of solvent at a constant temperature and pressure.

Solubility

Is the amount of solute that dissolves in a given quantity of a solvent at a specified temperature and pressure to produce a saturated solution.

Unsaturated Solution

A solution that contains less solute than a saturated solution at a given temperature and pressure.

Supersaturated Solution

Contains more solute than it can theoretically hold at a given temperature.

Miscible

Forming a homogeneous mixture when added together.

Immiscible

Liquids that are insoluble in one another.

Henry's Law

States that at a given temperature, the solubility of a gas in a liquid is directly proportional to the pressure of gas above the liquid.... Continue reading "Solutions and Solubility: Key Terms and Definitions" »

Experiment:Red Cabbage Indicator

Aim:To make our own indicator.

Background information:

• The Red Cabbage is red in acid solution

• Purple is a neutral solution

• Greenish-yellow is a base solution

• Red Cabbage contains a pigment molecule called FLAVIN(antocianina).

• The red cabbage juice will work over a wide pH range.To identified substances(acid or Bases)

Conclusion:The red Cabbage works as an indicator because we could identify the changes of each substance and classifies the bu colour of pH.For that we needed the ph scale.

Experiment :Acids and Bases

Aim:To find which substances are acid and bases by using different indicators

Materials:

1. Indicators(blue and red Litmus paper)

2. Samples

Procedure:Drop one drop of each substance on the indicators(the litmus

French Grammar

Passé Composé

• Subject + avoir/être (in present) + past participle
• Verbs with être: naître, mourir, aller, venir, arriver, partir, monter, descendre, passer, retourner, entrer, sortir, rester, tomber

Verbs Pouvoir and Vouloir

• Pouvoir: peux, peux, peut, pouvons, pouvez, peuvent
• Vouloir: veux, veux, veut, voulons, voulez, veulent

Questions

• Aimez-vous votre métier?
• Est-ce que vous aimez votre métier?
• Que préférez-vous aujourd'hui?
• Qu'est-ce que vous préférez aujourd'hui?
• Comment êtes-vous devenu réalisateur?
• Comment est-ce que vous êtes devenu réalisateur?
• Quels métiers avez-vous faits?
• Quels métiers est-ce que vous avez faits?

Exercer un Métier

• Avoir de l'imagination
• Être créatif(ve)
• Organisé(e)
• Sociable
• Résistant(e)
• Rapide
• Patient(