SOME BASIC CONCEPTS OF CHEMISTRY CLASS 11 NCERT CHEMISTRY

What is matter?

Anything that has mass and takes up space

STATES OF MATTER

solid, liquid, gas

CLASSIFICATION OF MATTER

pure substances and mixtures

PURE SUBSTANCE

A substance made of only one kind of matter and having definite properties.

MIXTURE

A combination of two or more substances that are not chemically combined

CLASSIFICATION OF PURE SUBSTANCE

elements and compounds

What are elements?

An element is a substance that cannot be broken down to other substances by chemical reactions.

What are compounds?

substances in which atoms of two
or more elements are chemically combined

CLASSIFICATION OF MIXTURES

homogeneous and heterogeneous

What is a homogeneous mixture?

a mixture in which the composition is uniform throughout

What is a heterogeneous mixture?

a mixture in which the composition is not uniform throughout and the substance are partially dissolved and leaves a bulk materials in a colloidal or suspended solution

length [l]

metre (m)

mass [m]

kilograms (kg)
(NOTE: NOT grams)

time [t]

seconds (s)

Eletrical Current [i]

ampere [A]

Temperature [T]

Kelvin (K)

amount of substance [n]

mole (mol)

luminous intensity [IV]

candela (cd)

WHAT IS MASS?

the amount of matter in an object

FORMULA OF MASS

DENSITY / VOLUME [OR] FORCE/ ACCELERATION

WHAT IS WEIGHT?

force of gravity on an object. measured in newtons.

FORMULA OF WEIGHT

mass x gravity

SI unit of weight

Newton

WHAT IS VOLUME?

The amount of space an object takes up

UNIT OF VOLUME

metres cubed (m^3)

What is density?

THE AMOUNT OF PARTICLES THAT ARE CLOSED PACKED

DENSITY FORMULA

mass/volume

DENSITY UNIT

kg/m^-3

WHAT IS ATOMIC MASS?

Number of protons and neutrons

The atomic mass unit is defined as

1/12 the mass of a carbon atom containing six protons and six neutrons

ATOMIC MASS IS ACTUALLY DEFINED AS

ATOMIC MASS IS A NUMBER WHICH TELLS HOW MANY TIMES AN ATOM OF AN ELEMENT IS HEAVIER THAN ONE ATOMIC MASS UNIT

HYDROGEN

1 U

CARBON

12U

NITROGEN

14 U

OXYGEN

16 U

SODIUM

23 U

MAGNESIUM

24U

ALUMINIUM

27U

PHOSPHRUS

31 U

SULPHUR

32 U

CHLORINE

35.5 U

POTASSIUM

39 U

CALCIUM

40 U

IRON

56 U

COPPER

63.5 U

WHAT IS MOLECULAR MASS?

The sum of the masses of all the atoms in a molecule

MOLE CONCEPT

the amount of substance that contains as many atoms, molecules, ions electrons, or any other elementary entities as there are carbon atoms in exactly 12 gm of 12 C.

Arogadro's number

6.022* 10^23

WHAT IS MOLAR MASS?

the mass in grams of one mole of a substance

1 MOLE OF ATOM IS EQUAL TO

1 GRAM

STATES OF MATTER

solid, liquid, gas