Solid state notes

Introduction/General characteristics of  Solids: 

There are three states of matter solid ,liquid and gas. Fluids  involve both liquids and gases because of their ability to flow.Solid is a state of matter in which the constituting particles are arranged very closely .The constituent particles can be atoms, molecules or ions. 

Properties of solids: 

• They have definite mass, volume and shape. 

• They are non compressible and rigid. 

• Intermolecular distances are very short and hence the intermolecular forces are strong. 

• Their constituent particles have fixed position. sand can only oscillate about their mean positions. 

Classification of solids on the basis of the arrangement of constituent particles: 

Properties of crystalline solid

• -A solid is said to be crystalline if its various constituent particles [ions, -atoms, molecules] are arranged in a definite geometric pattern in the three dimensional space so that there is short as well as long range order of constituent particles. 

• -They have a long range order.(means that there is a regular pattern of arrangement of particles which repeats itself periodically over the entire crystal. 

• -They have a sharp melting point. 

• -They are anisotropic in nature i.e. their physical properties(such as refractive index, conductivity, thermal expansion) show different values when measured along different directions in the same crystal. 

• -They have a definite characteristic heat of fusion. 

• -They are called true solids. 

• -When cut with a sharp edged tool , they split into two pieces and the newly generated surfaces are plain and smooth. 

• Example:- Sodium, Calcium, ,  NaCl and quartz etc. 

 polymorphs:   The different crystalline forms of a substance are known as polymorphic forms or polymorphs . For example: graphite and diamond.                         Characteristics of amorphous solids:

- If there is no regular arrangement of constituent particles or there is only the short range order of its constituent particles then the solid is called amorphous solid.                             

-They have a short range order.(In such an arrangement, a regular and     periodically repeating pattern is observed over short distances only. Such portions are   scattered and in between the arrangement is disordered. 

• -They gradually soften over a range of temperature. 

• -They are isotropic in nature i.e. their physical properties are the same in all directions. 

• -When cut with a sharp edged tool, they cut into two pieces with irregular surfaces. 

• -They do not have definite heat of fusion. 

• -They are called pseudo solids or super cooled liquids . This is because they have a tendency to flow, though very slowly. 

• Example:- Rubber, Glass, Pitch, Silica , quartz glass etc. 

• Note-supper cooled liquids: A liquid below its freezing point will crystallize in the presence of a seed crystal or nucleus around which a crystal structure can form. 

• Amorphous solids are very useful in everyday life such as: 

• -The glasses [Amorphous] are used in construction house ware, laboratory ware etc. 

• - A large no. of amorphous plastics is being used in forming no. of articles. 

• - Amorphous silica has found to be the best material for converting sunlight into electricity [in photovoltaic cells] 

 

CLASSIFICATION OF CRYSTALLINE SOLIDS:- 

Based upon nature of constituent particles and binding forces present in them:- 

A. Molecular Solids 

B. Ionic Solids 

C. Metallic Solids 

D. Covalent or Network Solids 

A. Molecular Solids 

• In these solids the constituent particles are molecules . they can further subdivided into following three types:- 

1. Non polar molecular solids:-     

    The crystalline solids in which constituent particles are atoms of noble gases [helium, neon] or non polar molecules like [H2, Cl2, I2] 

Their characters are:- 

-These are soft due to weak intermolecular forces(London force).

- are non conductors of electricity. They have low melting and boiling points. 

  Examples  - Tetra phosphorus decaoxide (P4O10), CO2, CCl4, I2, P4 

2. Polar molecular solids 

   -The crystalline solids in which constituent particles are polar molecules like HCl, SO2 etc. the intermolecular forces of attraction are dipole – dipole forces of attraction. 

-their characters are:- 

• They are soft; they are non conductors of electricity. 

• Their melting and boiling points are high then non polar solids. They exists gases or liquid at room temperature. 

3. Hydrogen bonded – molecular solids:- 

• In these solids the constituent particles are which contain hydrogen atom linked to high electronegative atoms as N, O, F 

• Their characters are:- 

• They exists as volatile liquids or gases at room temperature. 

• They are non-conductor of electricity. 

• Their melting and boiling points are high. 

• Eg: - H2O (ice), NH3.  

• • B. Ionic Solids 

  • Constituent Particles: Ions      

  • Bonding/Attractive Forces: Coulombic or Electrostatic 
    Electrical Conductivity: Insulators in solid state but conducts in molten state and in aqueous solutions 
    Physical Nature: Hard but brittle 
    Melting Point: High 

  • Examples: , ZnS, MgO, NaCl 

  C. Metallic Solids 

  • In natural the constituent particles are positively charged metal ions – and free electrons. 

  • They are formed of metal atoms which lose their valance electrons to left behind positively charged ions. 

  • These metal atoms are surrounded by the sea of electrons each metal atom contributes one or more electrons to this sea of electrons. 

  • Metallic bond:- 

  • The force that holds the metal kenels (part of metal without valence electrons) and mobile valence electrons in the crystal is called metallic bond. 

  • Properties of metallic solids:- 

  • They possess high electrical and thermal conductivity. 

  • They possess lusture and colour in some case due to presence of sea of free electrons. 

  • They are highly malleable and ductile. 

  • They are closely packed. They exhibit high melting points and high densities. 

  • Examples: Fe ,Cu, Ag, Mg 

  D. Covalent or Network Solids 

  • In these crystalline solids the constituent particles are non-metal atoms linked to adjacent atom by covalent bond throughout the crystal. They forms a network of covalent bonds and exists as giant molecules. Example: Diamond 

  Their main characteristics are:- 

  • As covalent bond is strong and directional in nature, these solid are very hard and brittle. 

  • Electrical Conductivity: Conductors in solid state as well as in molten state 

  • Physical Nature: Hard but malleable and ductile 

  • Melting Point: Fairly high 

  • Examples: , (quartz), SiC, C (diamond), C(graphite) 

   B. Ionic Solids 

  • Constituent Particles: Ions      

  • Bonding/Attractive Forces: Coulombic or Electrostatic 
    Electrical Conductivity: Insulators in solid state but conducts in molten state and in aqueous solutions 
    Physical Nature: Hard but brittle 
    Melting Point: High 

  • Examples: , ZnS, MgO, NaCl 

  C. Metallic Solids 

  • In natural the constituent particles are positively charged metal ions – and free electrons. 

  • They are formed of metal atoms which lose their valance electrons to left behind positively charged ions. 

  • These metal atoms are surrounded by the sea of electrons each metal atom contributes one or more electrons to this sea of electrons. 

  • Metallic bond:- 

  • The force that holds the metal kenels (part of metal without valence electrons) and mobile valence electrons in the crystal is called metallic bond. 

  • Properties of metallic solids:- 

  • They possess high electrical and thermal conductivity. 

  • They possess lusture and colour in some case due to presence of sea of free electrons. 

  • They are highly malleable and ductile. 

  • They are closely packed. They exhibit high melting points and high densities. 

  • Examples: Fe ,Cu, Ag, Mg 

  D. Covalent or Network Solids 

  • In these crystalline solids the constituent particles are non-metal atoms linked to adjacent atom by covalent bond throughout the crystal. They forms a network of covalent bonds and exists as giant molecules. Example: Diamond 

  Their main characteristics are:- 

  • As covalent bond is strong and directional in nature, these solid are very hard and brittle. 

  • Electrical Conductivity: Conductors in solid state as well as in molten state 

  • Physical Nature: Hard but malleable and ductile 

  • Melting Point: Fairly high 

  • Examples: , (quartz), SiC, C (diamond), C(graphite) 

    B. Ionic Solids 

  • Constituent Particles: Ions      

  • Bonding/Attractive Forces: Coulombic or Electrostatic 
    Electrical Conductivity: Insulators in solid state but conducts in molten state and in aqueous solutions 
    Physical Nature: Hard but brittle 
    Melting Point: High 

  • Examples: , ZnS, MgO, NaCl 

  C. Metallic Solids 

  • In natural the constituent particles are positively charged metal ions – and free electrons. 

  • They are formed of metal atoms which lose their valance electrons to left behind positively charged ions. 

  • These metal atoms are surrounded by the sea of electrons each metal atom contributes one or more electrons to this sea of electrons. 

  • Metallic bond:- 

  • The force that holds the metal kenels (part of metal without valence electrons) and mobile valence electrons in the crystal is called metallic bond. 

  • Properties of metallic solids:- 

  • They possess high electrical and thermal conductivity. 

  • They possess lusture and colour in some case due to presence of sea of free electrons. 

  • They are highly malleable and ductile. 

  • They are closely packed. They exhibit high melting points and high densities. 

  • Examples: Fe ,Cu, Ag, Mg 

  D. Covalent or Network Solids 

  • In these crystalline solids the constituent particles are non-metal atoms linked to adjacent atom by covalent bond throughout the crystal. They forms a network of covalent bonds and exists as giant molecules. Example: Diamond 

  Their main characteristics are:- 

  • As covalent bond is strong and directional in nature, these solid are very hard and brittle. 

  • Electrical Conductivity: Conductors in solid state as well as in molten state 

  • Physical Nature: Hard but malleable and ductile 

  • Melting Point: Fairly high 

  • Examples: , (quartz), SiC, C (diamond), C(graphite) 

   

  
  

   

   

solid state - important questions

1.Classify the following solids as crystalline and amorphous. 

    Sodium chloride, quartz glass, quartz, rubber, polyvinyl chloride, Teflon 

2.Categorize the give solids as metallic, molecular, ionic, amorphous or network (covalent). 

  (a) Tetra phosphorus decaoxide (P4O10)    

  (b) Ammonium phosphate (NH4)3PO4  

  (c)  SiC                                 

  d) I2                          

  e) P4

  f) Graphite              

 g) Brass                            

  h) Rb                        

  I) LiBr                                                     

 (j ) Si                       

 (k) Plastic 

3.why glass is considered as super cooled liquid? 

4.why the window glass of old buildings show milky appearance with time? 

5.why the glass panes fixed to window or doors of old building become slightly thicker at bottom? 

6.Sodium chloride is a crystalline solid. It shows the same value of refractive index along all the direction. True/False.  Give reason. 

7. Crystalline solid are anisotropic in nature. What does this statement means?

     [CBSE 2011] 

8. differentiate between a) Short range order and long range order   b)anisotropic 

and isotropic nature

9. Why are amorphous solids also called pseudo solids? 

solution and colligative properties (MCQ ,numerical type question) Class xii

1.Calculate the molality of a solution that contains 51.2 g of naphthalene, C10H8, in 500 mL of carbon tetrachloride. The density of CCl4 is 1.60 g/mL.

(a) 0.250 m

(b) 0.500 m

(c) 0.750 m

(d) 0.840 m

2. What is the molality of a solution labeled "8.6% glucose (C6H12O6) by weight?" (Note: If the question does not give the solvent, assume it is water.)

(a) 0.26 m

(b) 0.34 m

(c) 0.44 m

(d) 0.52 m

3. Calculate the mole fraction of C2H5OH in a solution that contains 46 grams of ethanol, C2H5OH, and 64 grams of methanol, CH3OH.

(a) 1/3

(b) 0.42

(c) 1/2

(d) 2/3

4. Which observation(s) reflect(s) colligative properties?

(I) A 0.5 m NaBr solution has a higher vapor pressure than a 0.5 m BaCl2 solution.

(II) A 0.5 m NaOH solution freezes at a lower temperature than pure water.

(III) Pure water freezes at a higher temperature than pure methanol.

(a) only I

(b) only II

(c) only III

(d) I and II

5. The vapor pressure of pure water at 85oC is 434 torr. What is the vapor pressure at 85 degree Celsius of a solution prepared from 100 mL of water (density 1.00 g/mL) and 150 g of diglyme, C6H14O3, a nonvolatile substance?

(a) 361 torr

(b) 390 torr

(c) 425 torr

(d) 388 torr

6.The vapor pressure of a solution containing a nonvolatile solute is directly proportional to the

(a) molality of the solvent.

(b) osmotic pressure of the solute.

(c) molarity of the solvent.

(d) mole fraction of solvent.

7. If 4.27 grams of sucrose, C12H22O11, are dissolved in 15.2 grams of water, what will be the boiling point of the resulting solution? (Kb for water = 0.512 oC/m) (Note: If the Kf and Kb are not given on the exam, you can find them on the back of the exam envelope.)

(a) 101.64  0C(degree Celsius)

(b) 100.42  0C

(c) 99.626  0C

(d) 100.73  0C

 8. What are the ideal van't Hoff factors for the following compounds:

Ba(OH)2, C6H12O6, K3PO4, HNO3 ?

(a) 1, 1, 1, 1

(b) 2, 1, 2, 2

(c) 3, 1, 4, 2

(d) 6, 3, 5, 5

9. Calculate the approximate initial boiling point (in oC) of a solution of 285 g of magnesium chloride in 2.0 kg of water. (Assume complete dissociation of the salt.)

(a) 103.1  0C (Degree Celsius)

(b) 101.6  0C

(c) 102.3  0C

(d) 100.8  0C

10. A solution made by dissolving 9.81 g of a nonvolatile nonelectrolyte in 90.0 g of water boiled at 100.37 oC at 760 mm Hg. What is the approximate molecular weight of the substance? (For water, Kb = 0.51 oC/m)

(a) 240 g/mol

(b) 150 g/mol

(c) 79 g/mol

(d) 61 g/mol

(e) 34 g/mol

11. What is the freezing point of an aqueous 1.00 m NaCl solution? (Kf = 1.86 oC/m) (Assume complete dissociation of the salt.)

(a) -1.86 0C (degree Celsius)

(b) +1.86 0C

(c) -3.72 0C

(d) -0.93 0C

12. A 17.3 mg sample of an organic compound (a non-electrolyte) was ground up with 420 mg of camphor to form a homogeneous mixture melting at 170.0 oC. What is the apparent formula weight of the organic compound? (Kf of camphor = 37.7 oC/m, m.p. of camphor = 178.4 oC) (Note: This is a freezing point depression problem - note the Kf of camphor - camphor is the solvent.)

(a) 353 g/mol

(b) 285 g/mol

(c) 231 g/mol

(d) 185 g/mol

13. Calculate the osmotic pressure associated with 50.0 g of an enzyme of molecular weight 98,000 g/mol dissolved in water to give 2600 mL of solution at 30.0 oC.

(a) 0.484 torr

(b) 1.68 torr

(c) 1.96 torr

(d) 3.71 torr

14. A 250 mL solution containing 21.4 g of a polymer in toluene had an osmotic pressure of 0.055 atm at 27 oC. What is the apparent formula weight of the polymer?

(a) 15,000 g/mol

(b) 18,000 g/mol

(c) 26,000 g/mol

(d) 38,000 g/mol

Class 10 Science chapter - 1 Chemical equations and reaction part -II

Q.1.Why should a magnesium ribbon be cleaned before burning in air?
Q.2  Write the balanced equation for the following chemical reactions.
 (i) Hydrogen + Chlorine → Hydrogen chloride
 (ii) Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride
 (iii) Sodium + Water → Sodium hydroxide + Hydrogen
Q.3.Write a balanced chemical equation with state symbols for the following reactions.
  (i) Solutions of barium chloride and sodium sulphate in water react to give insoluble barium   sulphate and the solution of sodium chloride.
  (ii) Sodium hydroxide solution (in water) reacts with hydrochloric acid solution (in water) to produce sodium chloride solution and water.

Q.4  A solution of a substance ‘X’ is used for white washing.
  (i) Name the substance ‘X’ and write its formula.
  (ii) Write the reaction of the substance ‘X’ named in (i) above with water.
Q.5  Why is the amount of gas collected in one of the test tubes in Activity 1.7(hydrolysis of water) double of the amount collected in the other? Name this gas.
Q.6  Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
Q.7  Identify the substances that are oxidised and the substances that are reduced in the following reactions.
       (i) 4Na(S)+O2(g)→2Na2O(S)
       (ii) CuO(S)+H2(g)→Cu(S)+H2O(l)