TyroCity: Chemistry Notes

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?

Environmental Pollution- Old is Gold

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

What is meant by acid rain? Give one major effect of acid rain.

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

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 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.

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?

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.

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.

Sulphur- Old is Gold

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

How is the moisture present in SO2 gas removed?
Acid rain forms when oxides of sulphur and nitrogen react with water. What are these oxides chemically?
Identify a viscous liquid that react with table sugar (C12H22O11) giving a charred (black) mass. Give the reaction involved.
Give two examples of reactions in which H2SO4 behaves as: (a) Strong acid (b) a dehydrating agent (c) an oxidizing agent
Explain with reason, why: (a) Conc. H2SO4 should always be added to H2O but never H2O to the acid? (b) Sugar is charred in contact with conc. H2SO4?
Write any two differences between the bleaching action of Cl2 and SO2.
What happens when H2S is passed through acidified potassium permanganate solution?
What happens when gas obtained by heating oxalic acid in presence of conc. H2SO4 is passed through heated caustic soda?
Write balanced chemical reactions for the laboratory preparation of: (a) Hydrogen Sulphide (b) Sulphurdioxide
What happens when a moist red flower is introduced into a gas jar containing SO2 gas?
Give a reaction of each to show: (a) SO2 as an oxidizing agent (b) H2S as an analytical agent

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

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?