Chemistry Notes Info - Your Chemistry Tutor provide notes for Classes, BSc, MSc, Chemistry Test: CHEMISTRY TERMINOLOGY

What are the factors which favor formation of ionic bonds?

What are the factors which favour formation of Ionic Bonds?

These are the factors which favours formation of ionic bonds...
1. One of the atoms i.e. Metal atom must have low ionization energy, so that it can easily lose its electrons.
2. Other atoms i.e. Non-Metal atoms must have high electron affinity, so that it can hold the extra electrons.
3. One of the atoms i.e. Metal atom should be large in size.
4. Other atoms i.e. Non-Metal atoms should be small in size.
5. Lattice energy of the crystal should be high, means the electrostatic attraction between charged ions in the crystal should be high.
6. Anion and cation should have inert gas electronic configuration
7. The combining elements should differ by at least 1.9 in electronegativity.

Chemistry Formulas for Nuclear Chemistry (Radioactivity)

Chemistry Formulas for Nuclear Chemistry (Radioactivity)

Empirical relationship between size of nucleus and its mass number is
            R = R0A1/3
Where,                       
            R = radius of nucleus,
            A = mass number,
            R0 = contestant = 1.4x10-13cm

Rate of Decayof radioactive substance

Where,
            K = decay constant,
            N = No. of atoms,
            t = time of decay,
            dN = small fraction of N,
            dt = small fraction of t

Value of Decay Constant

            
Where,
            N0 = No. of atoms originally present,
            N = No. of atoms present after time t

Half Life Time (t1/2)

            t1/2 = 0.693/K
Where,
            K = decay constant

Average Life Time (T)

            Average life time (T) =Sum of the lives of the nuclei/ Total number of nuclei
            T = 1/K 
Also,
            Average life time (T) = 1.44 x Half-life (T1/2)
Where,
            K = decay constant
            T = Average Life Time
            T1/2 = Half Life

Specific Activity

            Specific Activity = Rate of decay/m
                                      = KN/m
                                      = K x Avogadro Number/ Atomic Mass in gram
Where,
            N = Number of Radioactive nuclei that undergoes disintegration

Units of Radioactivity

            Standard unit of radioactivity is curie (c).
            1c = Activity of 1gram Ra226 = 3.7 x 1010dps
Where,
            dps = disintegrations per second
millicurie (mc) = 3.7 x 107dps
microcurie (µc) = 3.7 x 104dps
Other units of radioactivity are Rutherford (rd) and Becquerel (Bq).

Rutherford (rd)

1rd = 106dps

Becquerel (Bq)

            Becquerel (Bq) is the SI unit of radioactivity.
                        1Bq = 1 disintegrations per second
                        1 Bq = 1 dps

Radioactive Equilibrium

            A ----à B ----à C
            At steady state,
                        NA/NB = KB/KA = TA/TB
Where,
            KA = radioactivity constant for the process A---àB
            KB = radioactivity constant for the process B---àC
            TA = average life period of A
            TB = average life period of B
Radioactive Equilibrium in terms of half-life periods,
            NA/NB = (T1/2)A/ (T1/2)B

Chemistry Formula for Atomic Structure Part 2

Chemistry Formulas for Atomic Structure

Chemistry Formulas from Bohr’s Model of Atom

·         Angular momentum of electron in nth orbit


Where, m = Mass of the electron,
            v = velocity of electron,
            r = radius of the orbit,
            h = Planck’s constant,
            n = no. of orbit in which electron is present,

·         Energy of electron in nth orbit

            
           Where, Z = Atomic No. of Electron,

·         Energy absorbed or released in an electron jump ( E)

 

·         Radius of orbits of hydrogen like species

              
         For hydrogen atom Z = 1, for first orbit n = 1,
         On substituting values of the constants
         h = 6.62x10-27erg sec,
         m = 9.1x10-28g,
         e = 4.8x10-10
     we get,
    r = 0.529 Å
So, radius of first orbit of hydrogen atom is 0.529 Å.

·         Radius of nth orbits of hydrogen like species

rn = 0.529n2/Z Å

·         Velocity of electron in nth orbit

          
      On substituting values of the constants
      We get,

·         No. of revolution per second made by an electron around the nucleus of atom

·         Energy of electron in nth orbit (En)

       
        On substituting values of the constants
        We get,          
            
         In general,
                          

·         Energy of electron in a Hydrogen Atom in different energy levels

Energy Level
E (Joules/atom)
E (eV/atom)
E (kcal/mol)
1
-21.79x10-19
-13.6
-313.5
2
-5.42x10-19
-3.4
-78.4
3
-2.41x10-19
-1.51
-38.84
4
-1.36x10-19
-0.85
-19.6
5
-0.87x10-19
-0.544
-12.5
Infinite
0
0
0

·         Frequency or wave length of emitted radiation

          
            Where, λ = wavelength of emitted radiations
                        R = Rydberg constant for Hydrogen atom

·         Number of spectral lines produced when an electron drops from nth level to ground level

          

Chemistry Formulas from Photoelectric Effect

·         Planck’s Relationship,

E = hv

·         Total energy,

Total Energy = (mv2/2) + w
Where, w = energy required to remove the electron.

Chemistry Formulas from Wave Mechanical Concept of Atom

·         De Broglie’s Equation,

            
          Where, m = mass of particle,
                        v = velocity of the particle,
                        h = Planck’s Constant,
or,       
          

Chemistry Formulas from Heisenberg’s Uncertainty Principle

·        Heisenberg’s Uncertainty Principle,

            
           Where,   = uncertainty in the position of the particle,
                        = uncertainty in the momentum of the particle,
Also,
           
 

Chemistry Formulas from Quantum Numbers

·         Principle Quantum Number (n),

Maximum no. of electrons in n principle quantum number = 2n2

·         Azimuthal Quantum Number (l),

For the given value of principle quantum number (n), azimuthal quantum number (l), may have all integral values from 0 to (n-1)

·         Magnetic Quantum Number (m),

No. of orbitals in a sub-shell = 2 l +1

·         Spin Quantum Number (s),

For spinning of electron about its own axis

Carbonate Chemical Formula

Carbonate Chemical Formula and Description

Carbonate

It is a salt of the Carbonic Acid characterized by the presence of carbonate ion. Carbonate is a poly-atomic ion with the formula of CO2−
3


Chemical Formula of Carbonate

Carbonate CO2−
3


Structural Formula of Carbonate

Structural Formula of Carbonate

Chemical Properties of Carbonate

Metal carbonates decomposes on heating.

Example of S-Block Carbonates

H2CO3, Li2CO3, Na2CO3

Example of P-Block Carbonates

Al2(CO3)3 , NH4HCO3 , PbCO3

Example of D-Block Carbonates

MnCO3, FeCO3, Ag2CO3 

Humidity

What is Humidity?

The simple meaning of humidity is ‘atmospheric moisture’ or ‘amount of water vapor in the atmosphere’.
what is humidity
 Humidity is the amount of water vapors present in the atmosphere (or air). Water vapors are the gaseous state of water and are invisible.
 Humidity can be measured by three ways that are: absolute, relative and specific.
    1.   Absolute humidity is the water content of air in the gram per cubic meter at a given temperature.
     2.   Relative humidity is expressed in percentage, and it measures the current absolute humidity relative to the maximum humidity for that temperature.
    3.   Specific humidity is expressed as the ratio of the mass of the water vapors to the total mass of moist air parcel.

What is Absolute Humidity?

To understand absolute humidity let’s assume you are standing in ground and you collect some air. Now you check that air volume in your chemistry lab and get accurate amount of water vapors in gram. If you collect 1 cubic meter of air volume and it contains 30 gram water vapors than absolute humidity of that ground air is 30 grams per cubic meter. So, now you answer this question i.e. what is absolute humidity.
Absolute humidity (AH) is defined as the total mass (in gram) of water vapor present in a given volume (in cubic meter) of air. Absolute Humidity changes with changes in air temperature and pressure. Absolute humidity is the mass of the water vapors( m H 2 O ) {\displaystyle (m_{H_{2}O})} divided by the volume of the air and water vapor mixture.
AH = m/V
Where, AH = Absolute humidity,
             m = mass of the water vapors( m H 2 O ) {\displaystyle (m_{H_{2}O})},
             V = volume of the air and water vapor mixture.


What is Relative Humidity?

To understand relative humidity let’s assume you are in a building where air absolute humidity is 15 grams per cubic meter at 25 degree Celsius temperature and at 25 degree Celsius temperature highest amount of water vapors is 30 grams per cubic meter (saturated air with water vapors 15 grams per cubic meter). So, now you can calculate relative humidity as follows:
Relative humidity = (15 grams per cubic meter / 30 grams per cubic meter)x100
                            RH = 50%
So, now you answer this question i.e. what is relative humidity.
Relative humidity (RH) is defined as the ratio of the partial pressure of water vapors to the equilibrium vapor pressure of water at a given temperature. If temperature of the atmosphere is lower than relative humidity is higher as cold air (air with low temperature) holds more water vapors (moisture) but, If temperature of the atmosphere is higher than relative humidity is lower as hot air (air with high temperature) holds less water vapors (moisture).

What is Specific Humidity?

To understand specific humidity let’s assume you have an air parcel (air volume or some amount of air) and this parcel contains 10 gram mass of water vapors and total mass of air is 1 kg (including mass of all gases present in air and mass of water vapors) than specific humidity is 10 gram per kilogram. So, now you answer this question i.e. what is specific humidity.
Specific Humidity is defined as the ratio of the mass of water vapors in air to the total mass of the mixture of air and water vapors.
Specific Humidity = mass of water vapor/total mass of air

Difference between Humidity and Relative Humidity

Before going to discuss about “Difference between Humidity and Relative Humidity” we need to understand that what is humidity and what is relative humidity. And to get answer of these two questions just read above paragraph once again if you don’t understand.
Humidity is the amount of water vapors present in the atmosphere (or air). Relative humidity is expressed in percentage, and it measures the current absolute humidity relative to the maximum humidity for that temperature.


Older Posts

Subscribe To Get Latest Updates

Enter your email address:

Delivered by FeedBurner

Like Share and Comment to Support and Motivate us to write more…

Branches of Chemistry

Chemistry is branch of Science, which is further divided into many branches like-

Popular Posts

Chemistry GK

© Copyright Chemistry Notes Info - Your Chemistry Tutor provide notes for Classes, BSc, MSc, Chemistry Test Published.. Blogger Templates
Back To Top