IMPORTANT DEFINITIONS AND SOME POINTS
Diffusion : It is the random movement of particles from a region of high
concentration to a region of low concentration.
Kinetic particle theory
STATE
SOLID
LIQUID
GAS
Separation of
particles
Tounching
Touching one
another
Not touching
Arrangnment of
particles
Regular
arrangement
Randomly
arranged
Random
arrangnemnt.
Movement of
particles
They vibrate
Move over one
another
Random
movement
Proton number: The number of protons in the nucleus of an atom.
Nucleon number: The total number of protons and neutrons present in the
nucleus of an atom.
Element: A substance that cannot be broken down into two or more simpler
substances by chemical means.
Ion: an atom or group of atoms that has gained or lost electrons. Isotope: Atoms
of the same element with the same proton number and electron number but
different neutron number.
Difference between transition and alkali metals
Colour of halogens
Relative atomic mass: An average mass of naturally occurring atoms of an
element compared to an atom of 12C.
Relative Molecular Mass ( Mr): It is the sum of the relative atomic masses of the
elements present in a molecule
Relative Formula Mass is used for ionic compound
Mole : A mole of any substance is defined as the amount of substance that
contains as many particles (atoms, ions or molecules as there are atoms in exactly
12 g of carbon-12
Molecular formula : Molecular formula shows the actual number of atoms of
different element in a compound.
Empirical formula : The Empirical formula of a compound shows the simplest
ratio of the number of atoms of different elements in it
Compound: A substance made from two or more elements which are chemically
combined.
Mixture: Mixture contains two or more substances which are not chemically
combined.
Ionic lattice: Three dimensional regular arrangement of alternative positive ions
and negative ions.
Ionic bond: An electrostatic force of attraction between oppositely charged ions.
Covalent bond: A bond is formed between two atoms by a shared pair of
electrons.
Electrolysis: The break down of an ionic compound, molten or in aqueous
solution, by the passage of electricity.
Electrolyte: Liquids that conducts electricity by the movement of ions are called
electrolyte.
Inert electrodes: do not take part in reaction eg: graphite, platinum
Active electrode: takes part in the reaction. Eg: copper, zinc etc.
Electroplating :It is a process in which one metal is coated with another to make
it look better or to prevent corrosion
Acid: A substance which is proton (H+ ion) donor.
Base: A substance which is proton (H+ ion) acceptor.
Strong acid: The acids which completely ionize (dissociate) in water to give H+
ions are called strong acids. They produce a very high concentration of H+ ions in
water
Weak acid: The acids which partially ionize (dissociate) in water to give H+ ions
are called weak acids.
Precipitate: An insoluble solid which forms when two soluble solutions are
mixed.
Amphoteric oxide: An amphoteric oxide which will react with acids or with bases.
They behaves both as acidic or basic oxides.
Neutral oxide: A neutral oxide will not react with acids or with bases.
Saturated solution: A solution that can hold no more solute at the specified
temperature.
Alloy : Alloy is a mixture of metals or metals with non- metals that has different
properties from the metal elemetsthat make it.
Simple cell :Simple cell is a device which coverts chemical energy into electrical
energy
Activation energy : The minimum amount of energy needed for the particles to
react is called the activation energy
Catalyst: A substance which increases the rate of reaction without being
unchanged chemically at the end.
Reversible reactions: A reaction which takes place in both forward and reverse
direction.
Equilibrium: A reversible reaction in which the rate of forward reaction equals to
the rate of backward reaction and the concentration of the reactant and the
products are constant.
Fossil fuels: A fuel which is burn to release energy and take a long time to form
from organic material.
Biodegradable: A substance which can be broken down by microorganisms or
bacteria.
Hydrocarbon: Compounds containing carbon and hydrogen atoms only.
Structural isomers: Molecules with the same molecular formula and different
structural formula.
Homologous series :A family of similar compounds with similar chemical
properties due to the presence same functional group.
General Characteristics of Homologous series
 Same general formula
 Same functional group
 Consecutive member differ by -CH2
 Similar chemical properties
 Gradual change in physical properties
Cracking: The process by which large, less useful hydrocarbon molecules are
broken down into smaller, more useful alkanes and alkenes.
Addition reactions :A reaction where two molecules combine to give a single
product.
Substitution reaction: A reaction in which one atom or group is replaced by
another atom or group.
Saturated hydrocarbons – hydrocarbons with only single covalent bond between
carbon atoms.
Unsaturated hydrocarbons – hydrocarbons with at least one double or triple
covalent bonds between carbon atoms.
Fermentation: Breakdown of sugars by enzymes in yeast in the absence of oxygen
to form ethanol and carbon dioxide.
Esterification :The reaction between a carboxylic acid and an alcohol to produce
an ester and water.
Monomer: A small reactive molecule that reacts and joins together with itself or
another molecule to form the repeating units of a polymer.
Polymer: A large molecule made from many monomers joined together.
Polymerisation: The chemical reaction where monomers react to form a polymer.
Addition polymerization: the monomers have a C=C double bond. They combine
to form the polymer and no other compound is formed.
Condensation polymerisation: Two monomers joining with the removal of small
molecule to form a large molecule.