MATTER
Anything that has mass and occupies space is called matter.
According to the physical property of matter they are mainly classified as:-
- Solid
- Liquid
- Gas
Solid
- high intermolecular force
- fixed shape
- fixed volume
- high density
- very very low compressibility
Liquid
- low intermolecular force as compared to solids
- fixed volume but no fixed shape
- moderate density and low compressibility
Gas
- extremely low intermolecular forces
- neither fixed safe nor fixed volume
- very very compressible
Based on the chemical properties of matter they are generally defined in two ways:-
- Mixture
- Pure Substance
Pure Substance
- consist of a single type of particles
- all these particles are the same in their chemical
Pure substances are up to types:-
- Elements(metal, non metal, metalloid)
- Compound( inorganic, organic)
Mixture
- they are constituted by more than one kind of pure substances
Mixtures are further divided into two types:-
- Heterogeneous (non-uniform composition)
- Homogeneous ( uniform composition)
What is a mole?
Mole is the amount of substance that is equal to 6.022 ×10^23 entities.
The number of particles in a mole is equal to the number of atoms present in 12 grams of C-12 isotope.
- 1 mole = 6.022×10^23 entities
- The value of one mole is also written as an Avogadro number represented by Na
- No. Of moles= no. Of entities/Na
- No. Of moles= given mass/ molar mass
- No. Of moles= volume of gas/22.4liter
ATOMICITY
number of atoms present in a compound is called the atomicity of the compound.
No. Of moles= no. Of molecules×atomicity
Molecular formula
It represents the exact number of different atoms present in the molecule of a compound.
Empirical formula
It is the simplest ratio of atom present in a molecule and the ratio is always in the whole number.
Steps to find the empirical formula of a molecule:-
- Convert mass percentage in gram
- Calculate the number of moles of each element
- Divide the mole value of 10 ever by the smallest number
- If the mole ratio is fractional Den multiplies a suitable number and converts it into a simple ratio
- Write the empirical formula find moles and write the molecular formula
Note:- if the sum of the percentage of a constituent element of a compound is equal to 100 then the remaining is the percentage of oxygen.
BALANCED REACTION
- It contains an equal number of atoms of each element on both sides of the equation
- It should follow the law of charge conservation on either side
- Physical state of all reagents should be included in the bracket
- All reagents should be written in their standard molecular formula
- The coefficient gives the relation molar ratio of each reagent
LIMITING REAGENTS
The substance which is completely consumed in a chemical reaction is called the limiting the agent product is formed on its bases only.
STEP TO FIND LIMITING REAGENT
- Balance the chemical reaction
- Calculate and moles of every element or compound on the reaction side
- Divide the moles of reaction with their stoichiometric coefficient
- Direct and with which a minimum value of moles or stoichiometric coefficient is the limiting reagent
Parallel reaction
A chemical reaction in which a single reactant or pair of reactants produce more than two kinds of product simultaneously is a parallel reaction.
MOLARITY
The number of moles of solute present in 1 l volume of solution is called molarity.
MOLALITY
Several moles of solute present in 1 kg weight of the solvent is called molality.
DILUTION
The process of decreasing the concentration of a solute in a solution by mixing more solvents is called dilution.
NOTE:- if we know the molarity of a substance in a question it indicates that we know that most of the solute weight of solute and volume of solute
But if we know the molarity and density of the solution we know everything in the question.
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