🟩WATER HYACINTH🟩

☆ (Terror of Bengal)

★One of the most invasive weeds
Grows wherever there is standing water Drains oxygen from water- leads to death of fishes.

☆Introduced in India because of its pretty flowers & shape of leaves
Vegetative propagation occurs at a phenomenal rate

●Asexual reproduction is the most common method of reproduction in organisms having simpler body like in algae and fungi but during unfavorable condition they shift to sexual
reproduction.

🌀Perfect Experiment :

Gas Collection for Emission Spectra: a favorite demonstration using my set of pure samples of hydrogen, nitrogen and five noble gasses are subjected to the high frequency pulsed field of a miniature Tesla coil. Each gas has a characteristic breakdown voltage and emission spectrum- note that Nitrogen has the highest breakdown voltage and only glows when very near the coil where the field is most intense whereas Neon and Helium have the lowest breakdown voltage and begin to glow many centimeters away from the coil. The color of each gas is due to a mix of the colors emitted from electron energy transitions specific to each element- the basis of spectroscopy. The Krypton tube also exhibits interesting oscillations with this particular Tesla coil.

🔴MENSTRUAL CYCLE 🔴

♣︎ It occurs in monkeys, apes and human beings.
♣︎ Cycle consists of 3 phases-menstrual, proliferative and secretory phase.
♣︎Blood flows in the last few days of the cycle. The broken endometrium is passed out during
menstruation.
♣︎Female does not permit copulation during menstrual phase of the cycle.

🔵OESTROUS CYCLE 🔵

♣︎It occurs in non primates like cow, sheep, rat, deer, dog, tiger etc.
♣︎ It consists of a short period of oestrous or heat. it is 12-24 hours in cow followed by anoestrous or passive period.

♣︎Blood does not flow in this cycle. The broken endometrium is reabsorbed.

♣︎ Female permits copulation only during oestrous period.

♣︎Both in plants and animals, hormones are responsible for the transition between different
phases of life cycle.

★Interaction between hormones and environmental factors regulate the
reproductive processes.

[C]🟠 SENESCENCE PHASE 🟠 -

●It is the end of reproductive phase.
Old age ultimately leads to death

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👌👌Tricks for Conversions in Organic Chemistry

✅Haloalkanes can give you every possible functional group. They can also help you in increasing the chain size. So you might want to convert your starting material to haloalkanes and then go to the desired product

✅Remember the series of oxidation/reduction: Hydrocarbons (with various substituents) can be oxidised to alcohols, then appropriate carbonyl compounds and lastly carboxylic acids (or their derivatives)

✅Strong oxidizing agents are KMnO4 and K2Cr2O7

✅Mild oxidising agents depending on the situation are CrO4, Ammoniacal AgNO3, Benedicts Solution, Fehling’s solution, Cu or CuO at 573K, Bromine water etc.

✅Any carboxylic acid derivative can be converted back to the carboxylic acid by hydrolysis.

✅There are possibilities of hydride and methyl to get the most stable intermediate (carbocation/free radical)

✅A most common reaction, if your starting material is an alkane, is free-radical halogenation.

✅Saytzeff/Markovnikov's rules must be kept in mind while dealing with alkenes (they are based on the electron displacement effects only)

✅Decarboxylation and ozonolysis could go-to methods for decreasing the number of carbon atoms

✅Grignard reagent gives you the much-needed Alkyl nucleophile, which can be used at appropriate places.

Notes on Chemical Bonding

Chemical bond:-
Chemical bond is the attractive force which holds various constituents together in a molecule.

There are three types of chemical bonds: Ionic Bond, Covalent Bond, Co-ordinate Bond.

Octet Rule:
Atoms form chemical bonds in order to complete their octet i.e. eight electrons in their valence shell.

Lewis Structures:
Pair of bonded electrons is by means of a ‘dash’ (-) usually called a ‘bond’.

Lone pairs or ‘non-bonded’ electrons are represented by ‘dots’.

Electrons present in the last shell of atoms are called valence electrons.

Exceptions to the Octet Rule:
Species with odd number of electrons: NO, NO2,

Incomplete octet for the central atom: LiCl, BeH2 and BCl3

Expanded octet for the central atom: PF5, SF6 and H2SO4

Formal Charge:
Formal charge is the difference between the number of valence electrons in an isolated atom and number of electrons assigned to that atoms in Lewis structure.

Formal charge = [Total number of valence electrons in the free atom ) - (Total number of lone pairs of electrons) -1/2(Total number of shared electrons i.e. bonding electrons)]

Resonance:
For molecules and ions showing resonance it is not possible to draw a single Lewis structure.

All the properties of such species can only be explained by two or more Lewis structures. Example: Resonance of O3

Ionic Bonding:
Formation of Ionic Bond:
Formation of ionic bond takes place between a metal and a non-metal by transfer of electron.

Formation of gaseous cations

A(g) + I.E. → A+ (g) + e

Ionization Energy

Formation of gaseous anions

X(g) + e → X- (g) + E.A

Electron Affinity

Packing of ions of opposite charges to form ionic solids

A+ (g) + X- (g) →AX (s) +Energy

Lattice energy

Conditions required of formation of ionic bonds:

Low I.E of cation.

High E.A of anion.

High lattice energy.

Covalent Bonding:
Covalent bond is formed between two non-metals by sharing of electrons.

Electron pairs which participate in bonding are called bond pairs.

Electron pairs which do not participate in bonding are called lone pairs.

There could be single, double or triple covalent bonds between two elements depending on the number of electrons being shared.

VSEPR (Valence Shell Electron Pair Repulsion) Theory:
The shape of the molecule is determined by repulsions between all of the electron pairs present in the valence shell.

Order of the repulsion: Lone pair↔️ Lone pair > Lone pair↔️ Bond pair > Bond pair↔️ Bond pair.

Repulsion among the bond pairs is directly proportional to the bond order and electronegativity difference between the central atom and the other atoms.

💠Chemical Thermodynamics:💠
✅Basic Terminology:

➖System- Part of the universe under investigation.

➖Open System- A system which can exchange both energy and matter with its surroundings.

➖Closed System- A system which permits passage of energy but not mass, across its boundary.

➖Isolated system- A system which can neither exchange energy nor matter with its surrounding.

➖Surroundings- Part of the universe other than system, which can interact with it.

➖Boundary- Anything which separates system from surrounding.

➖State variables- The variables which are required to be defined in order to define state of any system i.e. pressure, volume, mass, temperature, surface area, etc.

➖State Functions- Property of system which depend only on the state of the system and not on the path. Example: Pressure, volume, temperature, internal energy, enthalpy, entropy etc.

➖Intensive properties- Properties of a system which do not depend on mass of the system i.e. temperature, pressure, density, concentration,

➖Extensive properties- Properties of a system which depend on mass of the system i.e. volume, energy, enthalpy, entropy etc.

➖Process- Path along which state of a system changes.

➖Isothermal process- Process which takes place at constant temperature

➖Isobaric process- Process which takes place at constant pressure

➖Isochoric process- Process which takes place at constant volume.

➖Adiabatic process- Process during which transfer of heat cannot take place between system and surrounding.

➖Cyclic process- Process in which system comes back to its initial state after undergoing series of changes.

➖Reversible process- Process during which the system always departs infinitesimally from the state of equilibrium i.e. its direction can be reversed at any moment.

➖Irriversible Process- This type of process is fast and gets completed in a single step. This process cannot be reversed. All the natural processes are of this type

📖Notes on Thermal Properties of Matter

Expansion in two dimensions (Superficial expansion):-
When the thermal expansion of a body is confined to a plane, it is to be two dimensional expansion or superficial expansion.

Coefficient of superficial expansion (β):- It is defined as the change in area of the surface per unit area at 0ºC, per degree centigrade rise of temperature.

β = St-S0/S0t

Expansion in three dimensions (Cubical expansion/volume expansion):- When thermal expansion of the body takes place in space, it is said to be three dimensional expansion or cubical expansion.
Coefficient of cubical expansion (γ):- Coefficient of cubical expansion is defined as the change in volume per unit volume, at 0ºC, per degree celsius rise of temperature .

γ = Vt-V0/V0t

Relation between expansion coefficients:-

(a) Relation between α and β: β = 2α
(b) Relation between α and γ: γ= 3α
(c) Relation between β and γ: γ = 3/2 β
(d) α : β : γ = 1:2:3

Thermal expansion of liquids:-

(a) Co-efficient of apparent expansion (γa):- The coefficient of apparent expansion of a liquid is defined as the apparent (or observed) increase in volume, per unit volume of the liquid at 0ºC per degree celcius rise of temperature.

γa = apparent increase in volume/(original volume at 0ºC) × (rise of temperature)

(b) Co-efficient of real expansion (γr):- The coefficient of real expansion of a liquid is defined as the real increase in volume, per unit volume of the liquid at 0ºC per degree centigrade rise of temperature.

γa= real increase in volume/(original volume at 0ºC) × (rise of temperature)

Work and Heat:-
Whenever heat is conserved into work or work into heat, the quantity of energy disappearing in one form is equivalent to the quantity of energy appearing in the order.

W∝H or W = JH

Joule’s mechanical equivalent of heat is defined as the amount of work required to produce a unit quantity of heat.

J = W/H

Value of J:- J = 4.2×107 erg cal-1 = 4.2 J cal-1

Specific heat capacity or specific heat (c):-

Specific heat capacity of a material is defined as the amount of heat required to raise the temperature of a unit mass of material through 1ºC.

c = Q/mΔT

Unit:- kcal kg-1K-1 or J kg-1K-1

Dimension:- M0L2T-2K-1

Molar specific heat capacity(C):-

Molar specific heat capacity of a substance is defined as the amount of heat required to raise the temperature of one gram molecule of the substance through one degree centigrade.
(a) C = Mc (Here M is the molecular weight of the substance)
(b) C = 1/n (dQ/dT)

Heat Capacity or Thermal Capacity:-

It is defined as the amount of heat required to raise the temperature of body through 1ºC.

Q = mcΔT

If ΔT = 1ºC, Q = heat capacity = mc

Unit:- kcal K-1 or JK-1

Water Equivalent:-

Water equivalent of a body is defined as the mass of water which gets heated through certain range of temperature by the amount of heat required to raise the temperature of body through same range of temperature.

w = mc

Water equivalent of a body is equal to the product of its mass and its specific heat.

Latent Heat:- When the state of matter changes, the heat absorbed or evolved is given by: Q = mL. Here L is called the latent heat.

(a)Specific latent heat of fusion (Lf):-

Specific latent heat of fusion of a substance is defined as the amount of heat required to convert 1 gram of substance from solid to liquid state, at the melting point, without any change of temperature.

(b) Specific latent heat of vaporization (Lv):-

Specific latent heat of vaporization of a substance is defined as the amount of heat required to convert 1 gram of liquid into its vapours at its boiling point without any rise of temperature.

Dimensional formula:- M0L2T-2

Unit:- kg cal kg-1 or J kg-1

Triple point of water = 273.16 K

Absolute zero = 0 K = -273.15ºC

For a gas thermometer, T = (273.15) P/Ptriple (Kelvin)

For a resistance thermometer, Re = R0[1+αθ]

✅Notes on s-Block Elements: Sodium Carbonate (Washing soda) (Na2CO3):

a) Preparation:

Solvay process:

Carbon dioxide gas is bubbled through a brine solution saturated with ammonia and itresults in the formation of sodium hydrogen carbonate.

NH3 + H2O + CO2 → NH4HCO3

NaCI + NH4HCO3 → NaHCO3 + NH4CI

Sodium hydrogen carbonate so formed precipitates out because of the common ion effect caused due to the presence of excess of NaCl. The precipitated NaHCO3 is filtered off and then ignited to get Na2CO3.
2NaHCO3 → Na2CO3 + CO2 + H2O

b) Properties

1. The aqueous solution absorbs CO2 yielding sparingly soluble sodium bicarbonate.

Na2CO3 + H2O + CO2 → 2NaHCO­3
2. dissolves in acids with an effervescence of carbondioxide and is causticised by lime to give caustic soda.

Na2CO3 + 2HCl →2NaCl + H2O + CO2

Na2CO3 + Ca(OH)2 → 2NaOH + CaCO3

3. Fusion with silica, sodium carbonate yields sodium silicate.

Na2CO3 + SiO2 → Na2SiO3 + CO­2
4. Hydrolysis – being a salt of a strong base (NaOH) and weak acid (H2CO3), when dissolved in water sodium carbonate. Undergoes hydrolysis to form an alkaline solution

Na2CO3 + 2H2O→ H2CO3 + 2NaOH
c) Uses

It is used for softening hard water.

A mixture of sodium carbonate & potassium carbonate is used as fusion mixture.

As an important laboratory reagent both in qualitative and quantitative analysis.

It is used in paper, paints and textile industries.

It is used for washing purposes in laundry.

It is used in the manufacture of glass, borax, soap and caustic soda.

Alkali Earth Metals (Group II elements of modern periodic table):
Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba) and Radium (Ra).

Physical Properties of Alkali Earth Metals:
1. Alkali earth metals are almost similar in properties to the corresponding alkali metals.

Higher melting points than alkali metals

Higher boiling points alkali metals

Higher densities alkali metals

Harder than the corresponding alkali metals

2. Atomic and ionic radii

The atomic radii as well as ionic radii of the members of the family are smaller than the corresponding members of alkali metals.

3. Ionization energy: The alkaline earth metals owing to their large size of atoms have fairly low values of ionization energies as compared to the p – block elements. However with in the group, the ionization energy decreases as the atomic number increases. It is because of increase in atomic size due to addition of new shells and increase in the magnitude of screening effect of the electrons in inner shells. Because their (IE)1 is larger than that of their alkali metal neighbours, the group IIA metals trend to the some what less reactive than alkali metals. The general reactivity trend is Ba > Sr > Ca > Mg > Be.

4. Oxidation state: The alkaline earth metal have two electrons in their valence shell and by losing these electrons, these atoms acquire the stable noble gas configuration. Thus, unlike alkali metals, the alkaline earth metals exhibit +2 oxidation state in their compounds.

🔰Notes on Wave Optics

Huygens Principle:- Wave-front of a wave, at any instant , is defined as the locus of all the particles in the medium which are being disturbed at the same instant of time and are in the same phase of vibration.

(a) Each point on a wave front acts as a source of new disturbance and emits its own set of spherical waves called secondary wavelets. The secondary wavelets travel in all directions with the velocity of light so long as they move in the same medium.

(b) The envelope or the locus of these wavelets in the forward direction gives the position of new wave front at any subsequent time.

Determination of Phase Difference:-
The phase difference between two waves at a point will depend upon

(a) The difference in path lengths of the two waves from their respective sources.
(b) The refractive index of the medium
(c) Initial phase difference between the source if any.
(d) Reflections, if any, in the path followed by waves.

Reflection of plane wave at plane surface (Laws of reflection):-

a) The incident ray, the reflected ray and normal to the reflecting surface at the point of incidence, all lie in one plane and that plane is perpendicular to the reflecting surface.
b) The angle of incidence is equal to the angle of reflection.

So, ∠i = ∠r

This signifies angle of incidence is equal to the angle of reflection.

Refraction of light:-
Refraction is the phenomena by virtue of which a wave going from one medium to another undergoes a change in velocity.

(a) The sine of the angle between the incident ray and the normal bears a constant ratio to the sine of the angle between refracted ray and the normal.

sin i/sin r = v1/v2 = 1µ2 = constant

Here, v1 and v2 are the velocities of sound in first and second medium respectively.1µ2 is the refractive index of the second medium with respect to first.

(b) The incident ray, the refracted ray and the normal to the refracting surface lie in the same plane.

Interference:- The modification in the distribution of light energy obtained by the superposition of two or more waves is called interference.

Principle of superposition:- It states that a number of waves travelling, simultaneously, in a medium behave independent of each other and the net displacement of the particle, at any instant, is equal to the sum of the individual displacements due to all the waves.

Displacement equation:- y = R sin 2π/λ (vt+x/2)

Amplitude:- R = 2a cos πx/λ

Intensity:- I = K4a2 cos2 (πx/λ) [I = KR2]

Maxima:- A point having maximum intensity is called maxima.

x = 2n (λ/2)

A point will be a maxima if the two waves reaching there have a path difference of even multiple of λ/2.

Imax = 4Ka2 = 4i (Here, i = Ka2)

Minima:- A point having minimum intensity is called a minima.
x = (2n+1) (λ/2)

A point will be a minima if the two waves reaching there have a path difference of odd multiple of λ/2.

Imin = K. 4a2×0 = 0

Condition for constructive interference:-
Path difference = (2n)λ/2

Phase difference = (2n)π

Condition for destructive interference:-
Path difference = (2n+1)λ/2

Phase difference = (2n+1)π

Coherent Sources:- Coherent sources are the sources which either have no phase difference or have a constant difference of phase between them.
Conditions for interference:-
(a) The two sources should emit, continuously, waves of same wavelength or frequency.

(b) The amplitudes of the two waves should be either or nearly equal

(c) The two sources should be narrow.

(d) The sources should be close to each other.

(e) The two sources should be coherent one.

Young’s double slit experiment:-
Path difference, x = yd/D

Maxima, y = nλD/d

Here, n = 0,1,2,3….

Minima, y = (2n+1) λD/d

Here, n = 0,1,2,3….

Fringe Width:- It is the distance between two consecutive bright and dark fringes.
β = λD/d

Displacement of fringes due to the introduction of a thin transparent medium:-
(a) Shift for a particular order of fringes:-

?y = (β/λ) (µ-1)t

(b) Shift across a particular point of observation:-

µ = (mλ/t) +1

Lloyd’s single mirror:-
?λ = β .2a/D

Power of lens:- P = 100/f

👌👌Tricks for Conversions in Organic Chemistry

✅Haloalkanes can give you every possible functional group. They can also help you in increasing the chain size. So you might want to convert your starting material to haloalkanes and then go to the desired product

✅Remember the series of oxidation/reduction: Hydrocarbons (with various substituents) can be oxidised to alcohols, then appropriate carbonyl compounds and lastly carboxylic acids (or their derivatives)

✅Strong oxidizing agents are KMnO4 and K2Cr2O7

✅Mild oxidising agents depending on the situation are CrO4, Ammoniacal AgNO3, Benedicts Solution, Fehling’s solution, Cu or CuO at 573K, Bromine water etc.

✅Any carboxylic acid derivative can be converted back to the carboxylic acid by hydrolysis.

✅There are possibilities of hydride and methyl to get the most stable intermediate (carbocation/free radical)

✅A most common reaction, if your starting material is an alkane, is free-radical halogenation.

✅Saytzeff/Markovnikov's rules must be kept in mind while dealing with alkenes (they are based on the electron displacement effects only)

✅Decarboxylation and ozonolysis could go-to methods for decreasing the number of carbon atoms

✅Grignard reagent gives you the much-needed Alkyl nucleophile, which can be used at appropriate places.