TyroCity: Chemistry 11 Notes

Define Van’t Hoff’s factor. What for it used?

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

Wiki- The van ‘t Hoff factor is the ratio between the actual concentration of particles produced when the substance is dissolved, and the concentration of a substance as calculated from its mass. For most non-electrolytes dissolved in water, the van’ t Hoff factor is essentially 1. For most ionic compounds dissolved in water, the van ‘t Hoff factor is equal
to the number of discrete ions in a formula unit of the substance. This is true for ideal solutions only. Sometime ion pairing occurs in solution. At a given instant a small percentage of the ions are paired and count as a single particle. Ion pairing occurs to some extent in all electrolyte solutions. This causes deviation from the van ‘t Hoff factor. The deviation for the van ‘t Hoff factor tends to be greatest where the ions have multiple charges.

i=van’t Hoff= the number of particles a formula breaks up into

C6H12O6(s) ==>C6H12O6(aq) (1 mole of particles) C6H12O6 =1

NaCl(s) ==> Na⁺(aq) + Cl^-(aq) (2 moles of particles) NaCl=2

CaCl2(s) ==> Ca²⁺(aq)+ 2Cl^-(aq) (3 moles of particles) CaCl2=3

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

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

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

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.

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?

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.

Verification of (Boyle's + Charles) Law

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

VERIFY BOYLE’S LAW WITH THE HELP OF K.M.T

According to Boyle’s law at constant temperature, pressure & volume of a gas are related as:

PV = constant

According to Kinetic theory, pressure of a gas is

VERIFY CHARLES LAW WITH THE HELP OF K.M.T
According to Charles law at constant pressure, absolute temperature & volume of a gas are related as:
V/T = constant
According to Kinetic theory, pressure of a gas is

Periodic Classification of Elements

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

Is a potassium atom larger, smaller or the same size as a potassium ion? Explain.
Why does the atomic size increase in going down any family of the periodic table?
Why do metals form positive ions and non-metals form negative ions?
Which of the following pairs would have a larger size and why? (a) K or K⁺ (b) F or F^-
Why does the first ionization energy increase from left to right in a given period of the periodic table?
Why ionization energy of alkali metals decreases as the atomic number increases?
Why do the Oxide O^-- and Sulphide S^-- have negative charge?
What is the basis of the classification of elements in Mendeleev’s periodic table?
Why do atomic radii decrease across a period and increase in a group with the increase of atomic number?
Arrange the elements Na, Li and K in the increasing order of first ionization energy.
Why is the ionization energy of Lithium greater than Sodium?
Compare the size of F^- and Na⁺ with the atomic size of Neon.
Why the size of Cl^- ion is larger than Cl atom where as the size of K⁺ ion is smaller than that of K atom?
State Modern Periodic law.
Why ionization energy of oxygen is less than that of nitrogen?
What is the basic difference between Modern Periodic Table and Mendeleev’s Periodic Table?

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

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

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

Alkali Metals

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

What is the main product obtained when sodium is allowed to react with dry ammonia at 300°-4000°C.
Why alkali metals cannot be obtained by chemical reduction method?
What are the chemical formulae of caustic soda, washing soda and baking soda? What are their main uses?
What happens when a piece of sodium is dropped into water?
What is the biological importance of sodium?
What would happen when the nitrate of an alkali metal is heated?

How is surface tension originated?

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

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.

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?

Carbon

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

Carbon monoxide is used as a reducing agent in metallurgy but not carbon dioxide. Why?
Give the laboratory method of preparation of carbon monoxide.
Define the terms ‘allotropes’ with examples.
What happens when carbon monoxide is passed over heated finely divided nickel?
What happens when a piece of burning magnesium is dropped into a jar full of carbondioxide?
What happens when oxalic acid crystals are heated with concentrated sulphuric acid?
Why is carbon used as the most common reducing agent in thermal metallurgy?
What is dry ice? Why it is called so?
Why is carbon monoxide extremely poisonous?
Give examples of crystalline allotropes of Carbon.
Write a chemical reaction to show the reducing action of CO.
How would you convert CO into CO2 and vice versa?
What happens when Carbon monoxide is heated with hydrogen in presence of ZnO and Cu?
Name the latest discovered allotropic form of carbon.
What happens when:

(a) Carbon monoxide is passed over finely divided nickel at 80°C.

(b) A gas obtained from a mixture of marble and dilute hydrochloric acid is passed into lime water till excess.

(d) Carbon monoxide is passed over finely divided nickel.