Chemistry Podcast

Showing posts with label Physical Chemistry Notes. Show all posts
Showing posts with label Physical Chemistry Notes. Show all posts

Sunday, 20 February 2022

10 Class- Acids, Bases and Salts

Acids Bases and Salts

·       Natural indicator of acids and bases – Litmus, Turmeric
·       Synthetic indicator of acids and bases – Methyl Orange, Phenolphthalein
·       Olfactory indicators of acids and bases - Odor of these substance changes in acids and bases.
pH scale for acid neutral and alkaline (or base) - Acid base strength indication by H and OH ion concentration
pH scale for Acid Neutral and Alkaline (or Base) & Acid Base strength indication by H and OH ion concentration


What is Acid?

Acids are the chemicals which can donate a proton or accept an electron pair in chemical reactions having pH less than 7 and changes color of blue Litmus to red.
Example- HCl, H2SO4


What is Base?

Bases are the chemicals which can accept a proton or donate an electron pair in chemical reactions having pH more than 7 and changes color of red Litmus to blue.
Bases which dissolve in water are called as Alkali
Example- NaOH


What is Salt?

Salt is a mineral or any neutral compound containing cations (+ve ions) attached with anions (-ve ions). 
Example- NaCl


Acids and Bases Reaction with Metals:-

                   Metal react with acid to form salt.
Acid + Metal ------> Salt + Hydrogen Gas
Similarly,
Metal react with base to form salt.
Base + Metal -------> Salt + Hydrogen Gas


Reaction of Metal Carbonates and Metal Hydrogen-Carbonates with Acids:-

Metal carbonates and metal hydrogen carbonates react with acids to form salt, water and carbon dioxide.
Metal Carbonate + Acid ----> Salt + Water + Carbon Dioxide
Example- Na2CO3 + 2HCl ---> 2NaCl + H2O + CO2
Similarly,
Metal Hydrogen Carbonate + Acid --> Salt + Water + Carbon Dioxide
Example- NaHCO3 + HCl ---> NaCl + H2O + CO2


Reaction of Acids with Bases:-

Reaction of acids with bases to form salt and water is called neutralization reaction.
Acid + Base ----> Salt + Water


Reaction of Acids with Metallic Oxides:-

Acids react with Metallic Oxides to form salt and water.
Acid + Metallic Oxide ----> Salt + Water


Reaction of Bases with Non-Metallic Oxides:-

Non-Metallic Oxides are acidic in nature so these react with bases to form salt and water.
Base + Non-Metallic Oxide ----> Salt + Water


Acids or Bases in Water:-

When acids dissolve in water they produce Hydrogen Ion H+(Aq) or Hydronium Ion (H3O+)
HCl + H2O ----> H3O+ + Cl-
H+ + H2O ---> H3O+
When bases dissolve in water they produce Hydroxide Ions (OH-)
NaOH + H2O -------> Na+(Aq) + OH-(Aq)


Reactions of Acids or Bases with Water are highly exothermic. Process of mixing Acid or Base with water decrease concentration of ions per unit volume, this process is known as dilution. 


Strength of Acids or Bases:-

Strength of acids depends on number of hydrogen ions (H+) produced and strength of bases depends on number of hydroxide ions (OH-) produced. A universal indicator (present on pH paper) is used to find strength of acids or bases.


pH Scale:-

It is a scale to measure hydrogen ion concentration in solution.
pH also known by seeing the color change in litmus paper.
Meaning of ‘p’ in ‘pH’ is “potenz”, which is a German word whose meaning is “power”.
pH scale measure pH from 0 (very acidic) to 14 (very alkaline).
pH of Neutral Solution is 7
pH of Acidic Solution is less than 7
pH of Basic Solution is more than 7


How to Measure PH of Acids and Bases ?

You can measure pH of acids and bases with the help of litmus paper, pH paper and pH meter. To know pH of any substance watch below pH experiment conducted by the Chemistry Notes Info. 


What is acid rain?

If pH of rain water is below 5.6 on pH scale than, that rain is called as acid rain.


Some Naturally Occurring Acids:-

Natural Source
Acid
Vinegar
Acetic Acid
Orange
Citric Acid
Tamarind
Tartaric Acid
Tomato
Oxalic Acid
Sour Milk (Curd)
Lactic Acid
Lemon
Citric Acid
Ant Sting
Methanoic Acid
Nettle Sting
Methanoic Acid


Common Salt:-

Common salt is very important raw material for production of other daily use material.


Sodium Hydroxide:-

Sodium Hydroxide is obtained by passing electricity through aqueous solution of sodium chloride (brine). Process is known as Chlor-Alkanization.   
2NaCl (aq) + 2H2O (l) ----> 2NaOH (aq) + Cl2 (g) + H2 (g)


Bleaching Powder (CaOCl2):-

Bleaching Powder is obtained by reaction between chlorine (Cl2) and dry slaked lime [Ca(OH)2].
Ca(OH)2 + Cl2 -----> CaOCl2 + H2O


Use of Bleaching Powder:-

·       For bleaching wood pulp in paper industry.
·       For bleaching washed clothes in laundry.
·       For bleaching cotton and linen in textile industry.
·       Used as oxidizing agent in chemical industry.
·       Used as disinfectant for drinking water to kill germs.


Baking Soda:-

Chemical name of baking soda is sodium hydrogen carbonate (NaHCO3). It is obtained by reaction between Sodium Chloride (NaCl), Water (H2O), Carbon Dioxide (CO2) and Ammonia (NH3).
NaCl + H2O + CO2 + NH3 ----> NH4Cl (Ammonium Chloride) + NaHCO3 (Sodium Hydrogen Carbonate)


Uses of Sodium Hydrogen Carbonate:-

·       To produce baking powder {mixture of baking soda + mild edible acid (like tartaric acid)}
·       Used to produce antacids (neutralize access acid in stomach to provide relief from acidity)
·       Used in soda acid fire extinguishers


Washing Soda:-

Washing soda is obtained by heating baking salt (Sodium Hydrogen Carbonate) and recrystallization of Sodium Carbonate produced above.
2NaHCO3 (Sodium Hydrogen Carbonate) + Heat --------> Na2CO3 (Sodium Carbonate) + H2O + CO2
Na2CO3 + 10H2O --------> Na2CO3.10H2O


Uses of Washing Soda:-

·       Used in glass, soap and paper industries
·       Used in preparation of sodium compounds like borax
·       Used as cleaning agent
·       Used for removal of permanent hardness of water

Crystal of Salt:-
Presence of fixed no. of water molecules in one formula unit of salt is called as water of crystallization.
·       Copper sulphate crystals with water molecule (CuSO4.5H2O) are blue in color, while
·        Copper sulphate crystals without water molecule (CuSO4) are white in color.


Plaster of Paris:-

Plaster of Paris is obtained by heating gypsum (CaSO4.2H2O) at 373K.
CaSO4.2H2O (Gypsum) + Heat ----> CaSO4.1/2H2O (Plaster of Paris) + 3/2H2O


Uses of Plaster of Paris:-

·       Used by orthopedic doctors for supporting fractured bones.

Friday, 4 February 2022

What is Viscosity in Chemistry

What is Viscosity in The Field of Chemistry

Viscosity
What is Viscosity
Do you know! “What is viscosity in chemistry“. To understand about viscosity, we take example of some liquids like Honey and Water. As we know honey is thicker than water. So honey flow with very slow speed on floor than water, as water is very less thick so it flows quickly. 
Hence we can say that liquids with high thickness (like honey) flow slowly and have high viscosity while a liquid with low thickness (like water) flows quickly and have low viscosity.

Example of Viscosity

To understand viscosity very well, just take few examples of viscosity in daily life.
  • Cooking Oil
  • Honey
  • Lubricant
  • Engine Oil
  • Brake Oil
  • Liquid Soap
These highly viscous liquids are some examples of viscosity in science. You known viscosity very well, even before listening this term viscosity in your physics & chemistry class.

Definition of Viscosity

Viscosity can be defined as the fluids resistance to flow.

What is Viscosity

In chemistry, Viscosity of a fluid is the measure of its resistance to gradual deformation by the tensile stress or shear stress. We can also say that viscosity is the internal resistance of the fluid. Fluids which have high viscosity resists to move as its molecular makeup gives this fluid a too much internal friction to motion, while fluids which have low viscosity resists less to move as its molecular makeup gives this fluid a less internal friction to motion.
So, we can say that molecular makeup decides internal friction between them and which ultimately provides viscosity of fluid. Honey has high internal friction than water so honey have high viscosity than water.

What is Meaning of Viscous

To understand viscosity. First, we learn what is the meaning of word “Viscous”. So, viscous is property of material i.e. material having a thick, sticky consistency between solid and liquid and also having a high viscosity. 

Who Poses Viscosity

Along with liquids or fluids, gases also have viscosity but it is very difficult to notice viscosity of gases at ordinary conditions.
We learn this chemistry topic under chemistry terminology category and Physical Chemistry Notes by Chemistry Notes Info ChemistryNotesInfo.com in simple way, we can say that, “Viscosity is the resistance of a fluid to change in its shape”,  viscosity is resistance to flow. Fluidity is the reciprocal of viscosity, So now we can say that honey has high viscosity and low fluidity while water has low viscosity and high fluidity.
Viscosity play very important role in determining characteristics of fluids used in lubrication and transportation, spraying, surface coating, injection molding etc.

Formula of Viscosity

Viscosity of any liquid can be calculated with viscosity formula. And viscosity formula is given below to calculate viscosity of any fluid or liquid.
Viscosity = Force×Time ∕Area

Newton’s Viscosity Law

According to the Newton’s viscosity law’, Shear stress between the two adjacent fluid layers is directly proportional to the velocity gradients between these two layers.

Unit of Viscosity

Unit of Viscosity is Newton second per Square meter (Ns/m2)
SI unit of viscosity is Pascal second (Pas)

Relation of viscosity with temperature

Viscosity of the liquids decreases quickly with increase in the temperature, while viscosity of the gases increases with increase in the temperature.
Temperature ->27 °C77 °C
Viscosity of Water0.85×10-3 pascal second0.36×10-3 pascal second
Viscosity of Air1.85×10-5 pascal second2.08×10-5 pascal second

Types of Viscosity

Viscosity is classified in two types. which are as follows-

1. Dynamic Viscosity

Dynamic viscosity is defined as the measure of the ratio of 'shear stress to shear rate' of the fluid.

Formula of Dynamic Viscosity
Dynamic Viscosity - Types of viscosity in science chemistry physics

2. Kinematic Viscosity
Kinematic viscosity is defined as the measure of ratio of 'viscous force to inertial force' on the fluid.

Formula of Kinematic Viscosity

Measurement of viscosity
Viscosity is measured by various types of Rheometers or Viscometers.
Viscometer

Monday, 31 January 2022

9 Class- Chemical Bonding and Reactions

Chemical Bonding and Reactions

Chemical Bonding

                             Molecule forms by the combination of two atoms of elements, the attraction force operate between atoms is known as Chemical Bonding. Chemical bonds are formed due to presence of valence electrons in atoms which present in outermost shell of atom.
Question: Why chemical bonds are formed between atoms?
Answer: Chemical bonds are formed between atoms to achieve stable state like inert or noble gases.
Atoms achieve stable state of nearest inert gas with complete octet in two ways:
1.     By exchanging electron with any other atom.
2.     By sharing electron with any other atom.

     Listen Chemical Bonding and Reactions Podcast Below-
       

Types of Chemical Bonds

  • 1.     Electrovalent Bond or Ionic bond

  • 2.     Covalent Bond

Electrovalent Bond
Electrovalent Bond is also known as Ionic Bond because compound formed is ionic in nature having polarity. In electrovalent bond one atom loose electron to form positive ion called cation and another which gain electron to form negative ion called anion. This type of bond is known as Electrovalent Bond or Ionic Bond.
Example: NaCl
        Na                    --------->   Na+ +e-
        Cl  +  e-            ---------> Cl-
        Na+  +  Cl-       --------->  NaCl

Electrovalent Compound

                             The compounds which contain ionic or electrovalent bonds are known as Electrovalent or Ionic Compounds. Mainly electrovalent compounds are formed due to reaction between highly electropositive and highly electronegative atoms.

Characteristics of Electrovalent Compounds

1.     Crystal Structure:

                              In solid state of electrovalent compounds anions and cations are arranged in regular manner called as crystal, In which anions surrounded by definite number of cations and cations surrounded by definite number of anions.

2.     Physical Nature:

       Ionic or electrovalent compounds are generally hard and their hardness increases with increasing ionic charge and decreasing distance between ions.

3.     Solubility:

Positive ion of ionic compound attach with negative part of polar solvent and negative ion of ionic compound attach with positive part of polar solvent, so ionic or electrovalent compounds are soluble in polar solvents like water and insoluble in non polar solvents like benzene, ether, alcohol.

4.     Melting Point and Boiling Point:

Electrovalent or ionic compounds have high Melting and boiling points because they need large amount of energy to break strong ionic bonds.

5.     Electrical Conductivity:

                                    In molten and solution forms electrovalent compounds conduct electricity because ions flows in molten and solution forms.

Covalent Compound

Covalent bonds are the bonds which are formed due to the equal sharing of electrons between two atoms.  These chemistry notes are provided by Chemistry Notes Info Organization www.ChemistryNotesInfo.com , This type of bonds (i.e. covalent bonds) is formed in atoms which carry four or more than four electrons in outermost shell, generally sharing of electrons happen in two ways –
1.     Equal Sharing – Covalent Bond
2.     One Side Sharing – Coordinate Bond

Covalent Compounds

                                   Compound which are formed as a result of covalent bonding and containing covalent bonds are known as Covalent Compounds.
Example: Hydrogen, Chlorine, Oxygen, Water, Ethanol etc.

Types of Covalent Bonds

Covalent Bonds are of three types which are as follows-

1.     Single Covalent Bonds

2.   Double Covalent Bonds

3.     Triple Covalent Bonds

Single Covalent Bonds

                                      Bonds which are formed due to sharing of single pair of electrons between two atoms are called single covalent bond. It is represented by single line (-)
Example: Formation of H2 molecule, Formation of Cl2 molecule.

i.                   Formation of Hydrogen (H2) molecule:

                                                         In the outermost shell of hydrogen atom, it have single electron, which it share with another hydrogen atom to acquire inert configuration of helium so single bond is formed between these two hydrogen atoms and this single covalent bond is represented by single line (-)

ii.                 Formation of Chlorine Molecule (Cl2) :

In the outermost shell of chlorine atom, it have seven electrons, it share its one valence electron with another chlorine atom to form chlorine molecule by single covalent bond.

Double Covalent Bonds

                                      Bonds which are formed due to sharing of double pair of electrons between two atoms are called double covalent bond. It is represented by double line (=)
Example: Formation of O2 molecule.

i.                   Formation of Oxygen (O2) molecule:

                                                          In the outermost shell of oxygen atom, it have six electrons, it share its two valence electrons with another oxygen atom to form oxygen molecule by double covalent bond.

Triple Covalent Bonds

                                      Bonds which are formed due to sharing of triple pair of electrons between two atoms are called triple covalent bond. It is represented by triple lines
Example: Formation of N2 molecule.

i.                   Formation of Nitrogen (N2) molecule:

                                                          In the outermost shell of nitrogen atom, it have five electrons, it share its three valence electrons with another nitrogen atom to form nitrogen molecule by triple covalent bond.

Characteristics of covalent compounds

1.     Crystal Structure:

                              Crystal structure of covalent compounds is formed from atoms or molecules. Crystal of covalent compounds are divided in three parts as –
i.                   These are crystals of covalent compounds whose molecule are very small and these molecules are held together by vander waals forces.
Example: Sulphur, Iodine.
ii.                 These are crystals of covalent compounds whose molecule are very large due to combination of every atom with other atom by covalent bonds.
Example:  Diamond, Silica.
iii.              These are crystals of covalent compounds whose have separate layers.
Example: Graphite.

2.     Physical Nature:

      Due to weaker force of attraction between the molecules of the covalent compounds, maximum covalent compounds are gases or liquids but some covalent compounds exist as solid like Urea, Sugar, Glucose, and Naphthalene.

3.     Solubility:

                Covalent compounds are not soluble in polar solvents like water but are soluble in non-polar solvent like alcohol, ether, carbon tetra chloride.

4.     Melting Point and Boiling Point ( MP and BP) :

                Melting and boiling points of covalent compounds are very low because very less energy is required to overcome the weak force of attraction between the neutral molecules in the covalent compound. But Diamond and Graphite are exception because they have very high melting and boiling points.

5.     Conductivity:

                   Covalent compounds do not have ions so they do not conduct electricity but some polar covalent compounds conduct very less electricity.

Polar Covalent Bond

                                    In the covalent compound if one is the more is more electronegative than other atom, then shared pair of electrons is attracted towards more electronegative atom so it acquire or obtain some partial negative charge which is represented by delta negative (d-) and other atom acquire some partial positive charge which is represented by delta positive (d+) therefore polar bond is form, which is known as Polar covalent bond.
Example : Hydrogen Chloride Molecule.
In HCl molecule, Chlorine is more electronegative than Hydrogen so chlorine acquires partial negative charge and hydrogen acquire partial positive charge.

Characteristics of Polar Covalent Compounds

i.                   Polar covalent compounds are approximately 80% covalent and 20% ionic so they so characteristics of both covalent and ionic (or electrovalent) compounds.
ii.                 In solution forms, polar covalent compounds are good conductor of electricity. Example: HCl
iii.              As compared to pure non-polar covalent compounds and electrovalent compounds, the melting point and boiling point of polar covalent compound are higher.

Chemical Reactions

Chemical Reaction is the reaction in which two or more than two substances react to form a new substance is known as Chemical Reaction. The substances which react may be ion or compound of element.
Reaction: Reactant reacts with each other to give product.
               Reactant   ---------> Product
Example of general chemical reactions from daily life is rusting of iron, formation of curd from milk etc.

Chemical Formula

                               Chemical Formula is simple representation of any compound by writing together the numbers and symbols of constituting elements forming that compound.
Example: H2O, CaCl2, AlCl3, Ca(OH)2

Chemical Formula for Ionic Compounds

                                                     As we know Ionic compound formed as a result of electron transfer between metal and non-metal atoms. When we have to write chemical formula for ionic compound then write metal atom symbol on left hand side and non-metal atom symbol on right hand side. Metal atom name remain same but ‘ide’ or ‘ate’ suffix is added to non-metal atom name.

Ionic compound formed by one metal atom and non-metal atoms.

Metal Atom
Non-Metal Atom
Name of Compound
Chemical Formula  of Compound
Name and Symbol
No.
Name and Symbol
No.
Calcium (Ca)
1
Oxygen (O)
1
Calcium Oxide
CaO
Magnesium (Mg)
1
Chlorine (Cl)
2
Magnesium Chloride
MgCl2
Aluminium (Al)
1
Chlorine (Cl)
3
Aluminium Chloride
AlCl3

    Chemical Formula for Covalent Compounds

                                                                        As we know covalent compound formed as a result of electron sharing and contains non-metal atoms. When we have to write chemical formula for covalent compound then relatively less electronegative non-metal atom symbol is written on left hand side and other witch is more electronegative is written  on right hand side. Name of non-metal atom which is written on left hand side is remain same but ‘ide’ suffix is added to non-metal atom name which is written on right hand side. 

Covalent compound formed by two  non-metal atoms.

Low Electronegative Non-Metal Atom
High Electronegative Non-Metal Atom
Chemical Name of Compound
Chemical Formula  of Compound
Name and Symbol
No.
Name and Symbol
No.
Carbon (C)
1
Oxygen (O)
1
Carbon Mono Oxide
CO
Carbon (C)
1
Oxygen (O)
2
Carbon Di Oxide
CO2
Phosphorus (P)
1
Chlorine (Cl)
3
Phosphorus Tri Chloride
PCl3
Phosphorus (P)
1
Chlorine (Cl)
5
Phosphorus Penta Chloride
PCl5
Nitrogen (N)
2
Oxygen (O)
5
Nitrogen Penta Oxide
N2O5

Formation of Compound

                                      We get chemical formula of molecule by writing valence of 1st atom in front of 2nd atom and valence of 2nd atom in front of 1st atom.
Example: valence of carbon is 4 and oxygen is 2, write 4 in front of O and 2 in front of C in subscripts as shown below.
C2O4
as we see, both valences are multiple of two so divide it by two to get CO2 formula.
Similarly,
           Na+ + CO3-2   ----> Na2CO3
          Al+3 + SO4-2  ---->  Al2(SO4)3
          Mg+2 + N-3    ----> Mg3N2

Simple Chemical Reaction

                                         Chemical reaction is represented by chemical equation in brief by taking help of symbol and formula of participating substances in reaction.

General Rule for writing Simple Chemical Reaction

   1.     Reactant are written on left hand side and if more than one reactant are present than write plus (+) sign between them.
   2.     Product are written on left hand side and if more than one product are present than write plus (+) sign between them.
   3.     Arrow sign is placed between reactants and products.
Example: Zn + H2SO4 ( Reactants)  -----> ZnSO4 + H2 (Products)
 4.     To get more information from the reaction write temperature, pressure, catalyst name above or below arrow sign. 
   5.     On the right side of the gaseous substances sign and on the left side of heavy substances which precipitate sign is placed.
   6.     Reactions which absorb heat are known as endothermic reactions and (+Q) heat sign is added on reactant side.
   7.     Reactions which produce heat are known as exothermic reactions and (+Q) heat sign is added on product side.
    8.     (Aq) is written for aqueous solution substances.

Balancing of Chemical Reactions

                                                    For balancing of chemical reaction the no. of atom on reactant side should be equal to no. of atom on product side, so that total mass of reactant is equal to total mass of product. You read these 9 class notes at www.ChemistryNotesInfo.com of ‘Chemistry Notes Info’ organization website.
H2 + O2   ----->   H2O   (Imbalance Equation)
2H2 + O2 ----->   2H2O   (Balance Equation)

Types of Chemical Reaction

  • ·        Addition Reaction

  • ·        Decomposition Reaction

  • ·        Substitution Reaction

  • ·        Oxidation and Reduction Reaction

1.     Addition Reaction

Reactions in which two or more than two substances reacts together to produce a new compound is known as Addition Reaction.
Example:-
2Mg + O2 ------> 2MgO

          2.     Decomposition Reaction

Reactions in which one compound get break into two or more than two simple compounds by breaking of chemical bonds, these chemical bonds get broken by heat, light or electricity.
Example:-
CaCO3 ------> CaO + CO2

          3.     Substitution Reaction

Reactions in which one element replaces another element to form a new compound is known as Substitution Reaction
Example:-
CuSO4 (Aq) + Zn (s) ------> ZnSO4 (Aq) + Cu (s)

          4.     Oxidation and Reduction Reaction

Oxidation and reduction reaction are described below on these two basis-
          Oxidation and Reduction Reaction based on oxygen and hydrogen-
·  Removal of hydrogen and addition of oxygen is known as oxidation reaction.
·  Removal of oxygen and addition of hydrogen is known as reduction reaction.
Oxidation and Reduction Reaction based on electron transfer-
·        Oxidation reactions are the reactions in which atom or ion looses electrons.
·         Reduction reactions are the reactions in which atom or ion gains electrons.
Oxidation and Reduction reactions occurs simultaneously because electron removed from one atom or radical is added to another atom or radical.
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