Some basic concepts of Chemistry Class 11th Notes - Free NCERT Class 11 Chemistry Chapter 1 Notes - Download PDF

Class 11 chapter 1 Some Basic Concepts of Chemistry is an introduction chapter that is highly important for students to grasp since it lays the foundation for chemical processes that occur all around us. Some basic concepts of Chemistry class 11 notes focus on the chapter Some basic concepts of Chemistry.

The purpose of CBSE Class 11 Chemistry chapter 1 notes, is to focus on a single topic and write concise, legible notes to assist you recall the key points before the test. The basic topics like nature and properties of matter, law of chemical combination, Dalton’s atomic theory, atomic and molecular mass, mole concept, etc are covered in the article Class 11 Some basic concepts of Chemistry note. Students who would like to pass CBSE Class 11 with a good score can read the cbse class 11 chemistry ch 1 notes.

This is only achievable if students have the top CBSE Class 11 Chemistry study materials and a well-thought-out study strategy. Some basic concepts of Chemistry notes class 11 made to help students with that. Hope that Class 11 Some basic concepts of Chemistry notes will assist students in understanding the major topics and remembering the key points for the exam. Class 12 Chemistry revision notes solution chapter 12 help students to get more complete explanation of these concepts. For more details students can refer to CBSE Class 11 Chemistry revision notes solution chapter 1.

Also, students can refer,

• NCERT Notes Class 11 Chemistry
• NCERT Solutions for Class 11 Chemistry Chapter 1 Some Basic Concepts of Chemistry
• NCERT Exemplar Class 11 Chemistry Chapter 1 Some Basic Concepts of Chemistry

NCERT Class 11 Chemistry Chapter 1 Notes

NCERT Class 11 Chemistry Chapter 1 Notes: Topic 1

Chemistry

Chemistry is a study that investigates the composition, structure, and properties of matter, as well as the changes that occur during chemical reactions. It is derived from the Egyptian word kme (chem), which means "earth." Because it connects physical sciences (including chemistry) with life sciences and applied sciences, chemistry is sometimes referred to as a core science (such as medicine and engineering).

The branches of chemistry are as follows

• Physical chemistry

The branch of chemistry that studies macroscopic and physical processes in the universe. It deals with the effect of a substance's physical properties on its chemical properties as well as its structure.

• Inorganic chemistry

Inorganic chemistry is the field of chemistry that investigates substances that do not contain carbon or hydrogen atoms. To put it another way, it is the reverse of organic chemistry. Metals, salts, and chemicals are examples of substances that do not have carbon-hydrogen bonds.

• Organic chemistry

Organic chemistry is the branch of science that studies the structure, content, and chemical characteristics of organic molecules. It entails the investigation of carbon and its compounds.

• Biochemistry

Biochemistry is the discipline of chemistry that studies the chemical processes that occur in and around organisms. It's a science that combines biology and chemistry in a laboratory setting. Biochemists can comprehend and address biological problems by applying chemical knowledge and technology.

• Analytical chemistry

It is a discipline of chemistry that employs equipment and analytical procedures to figure out a substance's structure, functionality, and qualities.

NCERT Class 11 Chemistry Chapter 1 Notes: Topic 2

Nature of Matter

Matter

Matter is defined as everything that takes up space and has mass. In general, matter is grouped into three categories

• Solids

Solids have the least flexibility of movement and have a distinct shape and volume. Eg : sugar, stone

• Liquids

The term "liquid" refers to a substance that has the shape of a container but has a fixed volume. Liquids also have the ability to flow or be poured. Water, milk, oil, mercury, and alcohol are few examples.

• Gas

Gases are substances that have neither a defined volume nor a defined shape. Gases usually entirely fill the container in which they are stored. For example, hydrogen, oxygen, and so on.

At the bulk or macroscopic level matter is classified into two

• Mixtures

• Pure substance

Mixtures

A mixture is a material that contains two or more chemicals in any proportion. It is mostly divided into two types heterogeneous and homogeneous mixtures

• Homogeneous mixtures

Homogeneous mixtures form when two substances are mixed to form a single uniform phase .In homogeneous mixtures the composition of substances present is uniform. Sugar solution and air are two examples of homogeneous mixtures.

• Heterogeneous mixtures

Heterogeneous Mixtures are those in which two or more substances are combined to produce a combination with a non-uniform composition. Suspensions, which are made up of two solids, such as salt and sugar, are one of the examples.

Pure substances

A pure substance is a material that contains only one type of particle. The following are the divisions of pure substances

• Elements

An element is a pure material that contains only one type of atom and can't be broken down any further. Silver, hydrogen , oxygen etc are examples.

• Compounds

A compound is a pure material made up of two or more elements combined together in a certain mass proportion. Furthermore, the properties of a composite differ from those of its constituent parts. Additionally, physical methods cannot separate the parts of a complex into simpler compounds. Chemical procedures are the only way to separate them. Examples include water, ammonia , carbon dioxide etc.

NCERT Class 11 Chemistry Chapter 1 Notes: Topic 3

Properties of Matter and Their Measurements

Every substance has its own distinct or distinguishing qualities.The two categories of attributes that are observed are physical and chemical properties.

Physical properties

Physical attributes are those that may be measured or observed without changing the identity or composition of a substance. Color, aroma, melting point, boiling temperature, density, and other physical characteristics are examples.

Chemical properties

Chemical properties are the characteristics of a substance that can be observed during a chemical reaction. Flammability, toxicity, heat of combustion, pH, radioactive decay rate, and chemical stability are some of the most important chemical properties.

Measurements

Physical quantities are those that we come upon during our scientific research. A physical quantity includes a number followed by a unit. The reference standard used to measure any physical quantity is referred to as a unit.

SI Units

The eleventh General Conference on Weights and Measures developed the International System of Units. The CGPM is an intergovernmental body established by the Meter Convention, a diplomatic convention signed in Paris in 1875. The SI system has seven base units. The seven essential scientific quantities are represented by these units. These quantities can be used to generate other physical quantities such as speed, volume, density, and so on.

Mass and weight

A substance's mass is the amount of substance it contains, whereas its weight is the force of gravity acting on the object. The mass of matter is constant, but its weight varies from place to place due to changes in gravity. The kilogramme is the SI unit of mass (kg). Newton is the SI derived unit of weight (derived unit of the SI base unit).

Volume

The amount of three-dimensional space surrounded by specific closed boundaries, such as the space occupied or contained by a material (solid, liquid, gas, or plasma), or the space occupied or contained by a shape. The most common way to measure volume is to use SI-derived units (cubic meters).

Density

A material's mass density, sometimes known as density, is defined as its mass per unit volume. The density is symbolized by the symbol ρ (the lowercase Greek letter rho). The SI unit for density is kilogrammes per cubic metre.

Temperature

The term "temperature" refers to a physical attribute of matter that quantifies the concepts of heat and cold. There are three popular temperature scales: (Celsius), (Fahrenheit), and (Fahrenheit) (Kelvin).

°F = 9/5(°C) + 32

K= °C +273.15

NCERT Class 11 Chemistry Chapter 1 Notes: Topic 4

Uncertainty in Measurements

In the study of chemistry, one must frequently deal with both experimental data and theoretical computations. There are practical methods for dealing with numbers and presenting facts in a realistic manner, to the extent possible.

Significant figures

All experimental measurements are subject to some degree of ambiguity. When we talk about measurement, precision and accuracy are frequently mentioned. Significant figures are digits that are certain to be relevant.

Precision

Precision refers to the consistency of different measurements for the same amount. Accuracy, on the other hand, is the agreement of a given value with the true value of the result.

Dimensional analysis

We frequently have to convert units from one system to another in calculations. The factor label approach, also known as the unit factor method or dimensional analysis, is used to do this.

NCERT Class 11 Chemistry Chapter 1 Notes: Topic 5

Laws of Chemical Combination

• Law of conservation of mass

“The mass in an isolated system can neither be created nor be destroyed but can be transformed from one form to another” According to the law of conservation of mass, in a low energy thermodynamic process the mass of the reactants must be equal to the mass of the products. This law is proposed by Antoine Lavoisier in 1789.

• Law of Constant / Definite Proportions

The mass proportions of the constituents in a composite sample are always the same, according to the law of definite proportions. It was given by Joseph Proust, a French chemist.

• Law of Multiple Proportions

When two elements are mixed to make more than one compound, the weight of one element is proportionate to the fixed weight of the other element as a whole number, according to the law of multiple proportions. Dalton proposed this law in 1803.

• Law of Reciprocal Proportions

When two different elements are mixed with the fixed mass of a third element, the combined mass ratio is the same, or a simple multiple of their combined mass, according to the law. Richter suggested this law in 1792.

• Gay Lussac’s Law of Gaseous Volumes

"The link between the volume of a gaseous reactant and a product can be represented by a simple whole number," according to Gay Lussac's law developed in 1808

• Avogadro Law

Avogadro postulated in 1811 that the number of molecules in equal quantities of gases at the same temperature and pressure should be the same.

NCERT Class 11 Chemistry Chapter 1 Notes: Topic 6

DALTON’S ATOMIC THEORY

Dalton wrote 'A New System of Chemical Philosophy' in 1808, in which he proposed:

• Atoms are the building blocks of matter.

• A given element's atoms all share the same properties, including the same mass. The mass of atoms in different elements differs.

• When atoms of different elements mix in a specific ratio, compounds are produced.

• Reorganization of atoms occurs during chemical processes. In a chemical reaction, they are neither generated nor destroyed.

NCERT Class 11 Chemistry Chapter 1 Notes: Topic 7

Atomic and Molecular Masses

Atomic mass

Atomic mass is defined as the mass of a single atom, expressed in atomic mass units (amu) or unified mass units (u)

1 a.m.u = 1/12 th mass of 1 carbon-12 atom

1 amu = 1.66056 × 10^-24 g

Average atomic mass

The average atomic mass of an element can be estimated from distinct isotopes of an element based on their relative abundance.

For example, there are three isotopes of C – (12C, 13C, 14C) with their relative abundance (%) – 98.892, 1.108, and 2 × 10^-10 with their atomic mass (AMU) as 12, 13.00335, and 14.00317 respectively.
The average atomic mass of carbon will be
=.(0.98892)(12 u) + (0.01108)(13.00335 u) + (2 × 10^-12)(14.00317 u)
= 12.011 u.

Molecular mass

The masses of the atoms that make up a molecule are added together to determine its mass. As a result, the two methods for measuring the mass of an atom, amu and g / mol, can also be used to represent the mass of a molecule.

Formula mass

Formula mass is used for compounds like NaCl in which positive and negative entities arranged in a three dimensional structure.

Formula mass of NaCl = Atomic mass of sodium + Atomic mass of chlorine

= 23.00 u + 35.5 u = 56.5 u.

NCERT Class 11 Chemistry Chapter 1 Notes: Topic 8

Mole Concept

Mole is a unit of amount of substance. A mole is defined as the amount of something that includes the same number of elementary particles (atoms, molecules, or ions) as 12 g of carbon dioxide (C-12).

1 mol of any substance contain 6.023 x 10²³ particles. 6.023 x 10²³ is known as Avagadro constant or Avogadro number.

Eg : 1 mole water = 6.023 x 10²³ water molecules

The mass of 1 mole of a substance is called molar mass.

NCERT Class 11 Chemistry Chapter 1 Notes: Topic 9

Percentage Composition

Mass% of an element = Mass of that element in the compound* 100Molar mass of the compond

Eg : Molar mass of water = 18.02 g/mol

Mass % of hydrogen = 2*1.00810018

= 11.18

Mass % of oxygen = 16*10018

= 88.79

NCERT Class 11 Chemistry Chapter 1 Notes: Topic 10

Empirical Formula and Molecular Formula

The compound's formula that gives the simplest whole number ratio of the atoms of various elements present in a single molecule is called empirical formula.

The actual ratio of the atoms of various elements present in one molecule of a compound is given by the substance's molecular formula.

NCERT Class 11 Chemistry Chapter 1 Notes: Topic 11

Stoichiometry

Stoichiometry is the study of chemical processes and the calculations. The stoichiometric coefficient is the coefficient that is utilized to balance the reaction. The stoichiometric coefficient, rather than the mass, is the ratio of moles of molecules of atoms that react. The stoichiometric ratio can only be used to forecast the number of moles of product generated when all reactants are present in a stoichiometric ratio. The real quantity of product created is always smaller than the theoretical calculation predicts.

NCERT Class 11 Chemistry Chapter 1 Notes: Topic 12

Limiting Reagent

If the reagents are not employed in a stoichiometric ratio, the limiting reagent, which is less than the needed amount, dictates how much product is created, and the excess reagent is called the excess reagent. When we burn carbon in the air (which has an infinite supply of oxygen), the amount of CO₂ created is proportional to the amount of carbon breathed. Carbon is the limiting reactant in this situation, whereas O₂ is the excess reactant.

NCERT Class 11 Chemistry Chapter 1 Notes: Topic 13

Reactions in Solutions

Because the two solids cannot react in the solid state, they must be dissolved in a liquid. When solutes dissolve in a solvent, they form a solution, which is a single phase in which they coexist. The strength of the solution is measured using several factors. The amount of solute in a solution is indicated by the strength of the solution.

• Mass percentage

It is the mass of the solute in grammes per 100 grammes of solution. A 10 % solution of sodium chloride, for example, contains 10 g of NaCl per 100 g of solution.

• Mole fraction

The mole fraction of any component of a solution is the ratio of that component's number of moles to the total number of moles of all the solution's components.

• Molarity

The number of moles of solute dissolved per dm3 (or litre, L) of a solution is referred to as its molarity. Temperature affects the molarity of any solution. As a result, any solution's molarity is specified for a specific temperature.

• Molality

The number of moles of solute per kg of solvent is the molality of a solution. If n moles of a solute are dissolved in W kg of solvent to make a solution,

Significance of NCERT Class 11 Chemistry Chapter 1 Notes

Class 11 Some basic concepts of Chemistry notes are helpful in understanding the principles of basic chemistry ideas in order to pass any scientific or research-related exam. This chapter also aids students in comprehending basic chemistry, and the NCERT Class 11 Chemistry chapter 1 notes make this procedure simple for them. chemistry class 11 chapter 1 notes pdf can be referred by students if they are not able to revise the chapter by NCERT for last minute revision.

CBSE Class 11 Chemistry chapter 1 notes can assist students in a variety of ways as the notes are a brief and concise explanation of chapter 1 of Chemistry Class 11. These notes will aid students in their preparation for examinations and other competitive exams like NEET, VITEEE, BITSAT, JEE MAIN, etc. chemistry class 11 chapter 1 notes pdf download can be used to prepare in offline mode.

NCERT Class 11 Notes Chapter-Wise

Subject Wise NCERT Exemplar Solutions

• NCERT Exemplar Class 11 Solutions
• NCERT Exemplar Class 11 Maths
• NCERT Exemplar Class 11 Physics
• NCERT Exemplar Class 11 Chemistry
• NCERT Exemplar Class 11 Biology

Subject Wise NCERT Solutions

• NCERT Solutions for Class 11 Mathematics
• NCERT Solutions for Class 11 Chemistry
• NCERT Solutions for Class 11 Physics

• NCERT Solutions for Class 11 Biology