TyroCity: Chemistry Notes

Ozone

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

Write resonance structures of ozone.
How does CFC deplet Ozone layer?

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.

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.

Define aqueous tension. Why is it subtracted from the total pressure to determine the pressure of a dry gas?

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

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.

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.

Metal and Metallurgical Principles

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

Name the process for concentration of sulphide ore.
Which metals can be extracted from the following ores:

Galena, cinnabar, argentite and zinc blend

Distinguish between calcination and roasting.
What is meant by aluminothermite process?
What is meant by Slag? Why is it important in metallurgy?
Which process is applied for the concentration of sulphide ore and why?
Can Sodium be extracted by the electrolysis of aqueous solution of sodium chloride? If not, why?
Distinguish between flux and slag with examples.

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.

Equivalent Mass

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

Equivalent weight of an element is 32.5. What does it mean?
Why is hydrogen displacement method not applicable to determine the equivalent mass of copper?
Define equivalent weight of an element. A divalent metal has atomic weight 24. What is its equivalent weight?
4gm of a divalent metal reacts with chlorine to produce 11.1gm of its metal chloride. Calculate the atomic mass of metal.

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

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?

Define coefficient of viscosity.

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.

Nuclear Chemistry

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

What are radioisotopes? State one use of such isotopes.