TyroCity: Chemistry Notes

Define coefficient of viscosity. How coefficient of viscosity is related with viscous force?

Chemistry 11 Notes — Sat, 12 Jul 2014 05:41:42 +0000

Ans: Coefficient of viscosity is defined as the tangential force per unit area required to maintain unit velocity gradient between the layers of liquid.

Chemistry XI Questions

Chemistry 11 Notes — Sat, 12 Jul 2014 05:41:42 +0000

Question Collection

NEB Model Question for Chemistry – Class 11

General and Physical Chemistry

Language of Chemistry

Language of Chemistry

Chemical Arithmetic

State of Matter: Gaseous State

Gaseous State

State of Matter: Liquid State

State of Matter: Solid State

Solid State

Atomic Structure

Atomic Structure

Nuclear Chemistry

Nuclear Chemistry

Electronic Theory of Valency and Bonding

Electronic Theory of Valency and Bonding

Periodic Classification of Elements

Periodic Classification of Elements

Inorganic Chemistry

Non-Metal I

Non-Metals II

Metal and Metallurgical Principles

Metal and Metallurgical Principles

Alkali Metals

Alkali Metals

Alkaline Earth Metals

Alkaline Earth Metals

Organic Chemistry

Introduction to Organic Chemistry

OTHER TOPICS

In terms of vapour pressure, what do you mean by a boiling point of a liquid?

Noble gas- Old is Gold

Chemistry 11 Notes — Sat, 12 Jul 2014 05:41:42 +0000

Why are noble gases chemically inert?
What are noble gases? Write any one use of noble gases.
The first ionization energy of noble gases is higher than that of halogens. Explain.
Give an important use of noble gases.

Why does boiling point of liquid rise on increasing pressure?

Chemistry 11 Notes — Sat, 12 Jul 2014 05:41:42 +0000

As the pressure applied to the liquid surface is increased, the energy needed for the liquid molecules to expand to gas phase also increases. Hence, a higher temperature is required to change liquid to gas phase. So, boiling point of liquid rises on increasing pressure.

Atomic Structure

Chemistry 11 Notes — Sat, 12 Jul 2014 05:41:42 +0000

Give the electronic configuration of copper (At. no. 29) in terms of s, p, d, f orbitals.
What is an orbital? Write the shapes of s and p orbitals.
Give the electronic configuration of silver (At. No. 47) in terms of s, p, d, f orbitals.
A scientist investing the electron structure of the element concluded that the K, L and M shells were all full and that the N shell contained four electrons. What is the atomic number of that electron?
For n=4, write all possible values of l and m.
Discuss how Bhors was able to predict the line spectra of a hydrogen atom.
Write the electronic configuration of Chromium (At. No. 24) in terms of s.p.d orbitals.
An atomic orbital has n=3, what are the possible values of l and m?
What are the values for n, l and m for 2Px orbital?
An electorn possesses the quantum numbers n=2, l=0 and m=0. What so they mean?
Write the atomic number of elements whode outermost electornic configuration are represented by (a) 3S1 (b) 3P6.
What observation did Rutherford led to conclude that the nucleus of atom is very small but heavy mass?
Why is it that electron does not jump into the nucleus?
What is meant by atomic spectrum?
Write the Lewis structure of the compound formed by two elements A and B whose atomic numbers are 12 and 17 respectively.
What are the values of Principal quantum number (n) and Azimuthal quantum number (l) for the following orbitals: (i) 3S (ii) 4P
An atom of an element has 24 electrons, what is the total number of S eletrons?
Give the values of all four quantum number of 11th electorn of Magnesium (At. No. = 12).
What observations did Rutherford make the following conclusions? a) The atomic centre is positively charged. b) Most of the space inside the atom is hollow.
Give the values of all four quantum number of outermost electron of sodium atom (Z=11).
What is Bhor’s-Bury rule?

Law of Chemical Equivalence

TyroCity.com — Sat, 12 Jul 2014 05:41:42 +0000

Eqv. Mass of A / Eqv. Mass of B = Mass of A / Mass of B

This relation tells that the combining mass reactants is always in the ratio of their equivalent mass. This law is also known as LAW OF CHEMICAL EQUIVALENCE.

Atomic Mass = Eqv. Mass X Valency
‘Gram Eqv.’ or ‘Eqv.’
Eqv. mass of a substance, expressed in gram is ‘one gram equivalent’ or ‘1 eqv.’

Equivalent Mass of a compound

a) Eqv. mass of acid = Molecular Mass of acid / Basicity

where Basicity of an acid is defined as no. of H+ ions displaced or OH- ions combined per molecule of the acid.

Eqv. mass of H2SO4 = 98 / 2 = 49

b) Eqv. mass of Base = Molecular Mass / Acidity

where acidity of the base is defined as the no. of H+ ions consumed or OH- ions displaced per molecule of the base.

Eg.
Eq. Mass of Ca(OH)2 = 74/2 = 37

c) Eqv. mass of Salt = Molecular Mass of Salt / Total no. of charge in basic or acid radical per molecule

Eg.
Eq. mass of Na2CO3 = 106 / 2 = 53

Liquid State Answer

TyroCity.com — Sat, 12 Jul 2014 05:41:42 +0000

1. Name the physical property behind rise of liquids in capillary tube.
Ans: Surface Tension

2. Define aqueous tension. Why is it subtracted from the total pressure to determine the pressure of a dry gas?
Ans: Aqueous tension is defined as the partial pressure of the water vapour present in the moist gas.
When the gas is colleced over the water, it becomes moist due to presence of small quantity of water vapour caused by evaporation.

Then, pressure exerted by moist gas = pressure exerted by dry gas + pressure of water vapour (aqueous tension).

i.e. Pmoist = Pdry + f (aqueous tension)

or, Pdry = Pmoist – f

Therefore, aqueous tension should be subtracted from the total pressure to get pressure of the dry gas.

3. What is evaporation? How does it differ from boiling?
Ans: Evaporation is defined as the process of conversion of liquid into vapour from the surface of the liquid at room temperature.

Evaporation Boiling

It takes place at any temperature. It takes place at boiling point only.

It takes place at the surface of liquid. It takes place at the entire volume of the liquid.

It is slow and silent process. It fast and noisy process.

4. Define coefficient of viscosity. How coefficient of viscosity is related with viscous force?

Ans: Coefficient of viscosity is defined as the tangential force per unit area required to maintain unit velocity gradient between the layers of liquid. (……………….)

5. Why is Glycerine more viscous than water?
Ans: Because the intermolecular force is large in glycerine than in water.

6. Why is a mercury droplet spherical?

Ans: Due to surface tension. Surface tension is the property of liquid due to which it tries to aquire minimum surface area. Since, for a given volume sphere has a minimum surface area, a mercury droplet is spherical.

7. In terms of vapour pressure, what do you mean by a boiling point of a liquid?

Ans: Boiling point is the temperature at which the vapour pressure becomes equal to atmospheric pressure.

8. The meniscus for mercury in a glass tube is concave downward. Explain.

Ans: Because cohesive force between molecules of mercury is greater than the adhesive force between mercury and glass molecules.

9. What do you understand by viscosity?

Ans: Viscosity is defined as the property of fluid by virtue of which an internal friction comes into play when the fluid is in motion and opposes the relative motion of its different layers.

10. What is the effect of temperature on: (a) Surface tension (b) Viscosity (c) Vapour pressure of liquid
Surface tension: It decreases on increase in temperature and vice versa.
Viscosity: It decreases on increase in temperature and vice versa.
Vapour pressure: It increases with increase in temperature and vice versa.

11. What do you understand by the term ‘surface tension’?
Surface tension is defined as the property of the liquid due to the intermolecular focre of attraction between the liquid molecules due to which liquid tries to gain minimum surface area.

12. How is surface tension of a liquid originated?

13. Define Vant Hoffs factor. What for it used?

14. What do you mean by boiling point and evaporation?
Boiling point is the temperature at which the vapour pressure becomes equal to atmospheric pressure.
Evaporation is defined as the process of conversion of liquid into vapour from the surface of the liquid at room temperature.

16. Give reason:

a) Falling liquid drops are spherical.
Due to surface tension. Surface tension is the property of liquid due to which it tries to aquire minimum surface area. Since, for a given volume sphere has a minimum surface area, a mercury droplet is spherical.

b) Evaporation takes place from the surface of liquid.
Since, the kinetic energy of the surface molecule is greater than the bulk molecule, evaporation takes place from the surface of liquid.

c) It is more efficient to wash clothes in hot water than cold water.
Surface tension decreases on increase in temperature. Due to this hot water can wet the clothes more effectively then cold water. So, it is more e to wash clothes in hot water than cold water

17. What happens to the vapour pressure of a solvent, when non volatile solute particles are dissolved in it?

A non volatile solute particle lowers the vapour pressure of solvent because solute particles become surrounded by solvent particles when dissolved. This causes the particles of solvent to evaporate less because it requires more energy for the particles to do this since the solvent to solute attraction are strong. So the vapour pressure of a solution is less than that of the pure solvent.

Vapour pressure depends on

Nature of liquid
Temperature
Presence of impurities

18. Why does boiling point of liquid rise on increasing pressure?

19. Mention physical properties of liquid due surface tension.
Spherical shape of liquid drop.
Rise and fall of liquid in a capillary tube.

Mention physical properties of liquid due surface tension.

Chemistry 11 Notes — Sat, 12 Jul 2014 05:41:42 +0000

Spherical shape of liquid drop.

Rise and fall of liquid in a capillary tube.

Phosphorous- Old is Gold

Chemistry 11 Notes — Sat, 12 Jul 2014 05:41:42 +0000

Name different amorphous forms of phosphorous.
Write the Lewis structure of orthophosphoric acid and phosphate ions.
What happens when white phosphorus is heated with aqueous caustic soda?
How is white phosphorous converted to red phosphorous and vice versa?
What is the effect of heat on ortho phosphoric acid?
What happens when white phosphorous is exposed to air?
Write chemical action of white phosphorous on conc. Nitric acid.
Write chemical action of white phosphorous on aqueous KOH solution.
Give an important use of each of Red Phosphorous.
Name any two allotropes of phosphorous. Why is phosphorous stored in water?
What happens when: (a) White phosphorous is heated with concentrated solution of Caustic Soda? (b) The gas produced by the action of white phosphorous with sodium hydride is passed through silver nitrate solution?

Name the physical property behind rise of liquids in capillary tube.

Chemistry 11 Notes — Sat, 12 Jul 2014 05:41:42 +0000

Ans: Surface Tension

Fundamental Principles- Old is Gold

Chemistry 11 Notes — Sat, 12 Jul 2014 05:41:42 +0000

For detection of elements (N, X, S) in organic compounds, why is sodium fusion carried out?
Write the structures of the following organic compounds:

(a) 2-methyl propan-1-ol

(b) 3-methyl butanoic acid

(d) 2,2-dimethyl propane

(e) 2-ethyl pent-1-ene

(f) 2-chloro-2,3-dimethyl pentane

Why is aqueous solution of sodium extract alkaline?
Define an electrophile and nucleophile giving an example from each.
Why is it necessary to prepare sodium extract for the detection of foreign elements in organic compounds?
Write short notes on Homologous series.
What are anti-knocking reagents? Name one important anti-knocking agent.
How would you detect the presence of nitrogen and sulphur together in the organic compound?
Why is Lassagne’s extract boiled with concentrated nitric acid while testing for halogen?
What is the function of Tetraethyl lead (TEL) in gasoline?
Write down the structure formulae of the third member of the following homologous series:

(a) Alkanamide

(b) Alkanol

(d) Alkanoic acid

Homologous Series

TyroCity.com — Sat, 12 Jul 2014 05:41:42 +0000

Definition

A series of organic compounds that have similar structural features but differ from adjacent members by (-CH2) group is referred to as homologous series. Each member of homologous series is called homolog.

Example

CH3-OH, CH3-CH2-OH, C3H7-OH are the members of a homologous series called "Alcohols".
CH3-COOH, CH3-CH2-COOH, C3H7-COOH are the members of homologous series called "Carboxylic acids".
CH3-O-CH3, C2H5-O-CH3, C3H7-O-CH3 are the members of homologous series called "Ethers".

Characteristics of Homologous Series

1. Structural Forumla
All the members of a homologous series have same structural formula.

2. Molecular Formula
Molecular formula of different members of a homologous series differs from previous and next member by CH2.

3. Nature of Element
All the members of series have same type of elements.

4. Functional Group
All the members of homologous series contain same functional group.

5. General Forumla
Members of a homologous series can be represented by a general formula.

For example:
ALKANE : CnH2n+1
ALKENE : CnH2n
ALKYNE : CnH2n-2
ALCOHOL : CnH2n+1 OH
ETHERS : CnH2nO
Where n = number of carbon atoms.

6. Molecular Mass
Molecular mass of any two consecutive members differ by 14 units

7. Chemical Properties
All the members of a homologous series have same chemical properties due to same functional group.

8. Methods of Preparation
Generally all the members of a series can be prepared by using same method.

9. Physical Properties
Physical properties of the members of a homologous series vary with the increase in atomic weight.