TyroCity: Chemistry Notes

Bulk molecule feels force from all direction since it has molecules in all direction due to which resultant force
becomes zero but surface molecules only feels inward force since it lies at the surface due to which the resultant force in surface molecules is not zero. Resultant force is in inward direction for surface molecules. Because of this, the surface molecules acts as a stretched membrane and is attracted inward finally resulting surface tension. This is how surface tension is originated.
In short, surface tension is originated due to unequal existence of cohesive force felt by surface molecules of liquid as in above figure.

Dalton’s Atomic Theory and Laws of Stoichiometry

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

State the Law of Multiple Proportions.
State the law of Constant Proportion.
State the Law of Reciprocal Proportion.
How did the law of multiple proportions encourage Dalton to introduce atomic theory?
H and O react separately to give H2O2 and H2O respectively. What law of stoichiometry is illustrated? State the law.
Phosphorous reacts with oxygen to produce P2O3 and P2O5 respectively. Which Chemical law does the data illustrate? State the Law.
State the Law of conservation of mass. Why is this law known as Law of indestructibility of matter?
12gm of Carbon react with 32gm of oxygen to produce 44gm of Carbon dioxide. Which Chemical Law do these data illustrate? State the Law.

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.

Halogens (Chlorine, Bromine and Iodine)

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

Why halogens are never found in the Free State in nature?
A test tube contains a solution of one of the following salts: NaCl, NaBr and NaI. Describe a single test that can distinguish among these salts.
Give any one chemical reaction to prepare chlorine gas from hydrochloric acid.
Give a chemical reaction to show oxidizing action of chlorine.
How would you obtain bromine from HBr?
What happens when KBr is heated with conc. H2SO4 acid?
Why can’t HI be prepared by the action of conc. H2SO4 on NaI?
Give the action of

(i) KI on copper sulphate solution

(ii) Heat on lime stone.

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

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.

Oxygen

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

Write the names of any two neutral oxides with their formulae.
What are neutral and amhoteric oxides? Give one example of each.
What are oxides? Classify the following oxides justifying the classification: a) NO b) CO2 c) ZnO d) CaO
Mention one example of each of the following: i. Allotrope of oxygen ii. Amphoteric oxide iii. Most abundant isotope of hydrogen iv. Neutral oxide

Empirical, Molecular Formula and Limiting Reactants

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

What is limiting reactants? Why is it essential in stoichiometric calculations?
10.6gm of pure Na2CO3 if treated with 7.9gm of HCl to produce NaCl, H2O and CO2, (5 marks)

a) Find the limiting reactants and calculate mole of unreacted reagent left over.

b) What volume of CO2 gas is produced at NTP?

c) Calculate the mass of NaCl formed.

A chemical reaction was carried out by mixing 25gm of pure Calcium Carbonate and 0.75 mule of pure hydrochloric acid to give CaCl2, H2O and CO2. (5 marks)

a) Which one is the limiting reactant and why?

b) Calculate the mass of CaCl2 produced.

c) How many numbers of water molecules are formed?

d) What mass of NaOH is required to absorb the whole CO2 produced in the reaction?

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

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

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
A· Nature of liquid
B· Temperature
C. Presence of impurities

Boron and Silicon- Old is Gold

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

Write the formula of Borax and boric acid.
Give an important use of Silicon.

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.