Question

Post your summary of the chapter on Liquids and Solids.

For maximum point,

1) Your post must be very detailed and informative (not less than 200 words).

Answer 1

Solids are categorised into two types namely: Amorphous and Crystalline solids.

Crystalline solids are further broke down into various categories like:

a. Ionic solids: Solids held together by strong electrostatic forces of attraction between the constituent ions. They have high melting and boiling points and are soluble in water. Eg: NaCl

b. Molecular solids: Solids composed of moelcules which may have London dipersion forces or dipole-dipole interaction or hydrogen bonding acting in them. Melting and boiling points are comparatively lower than ionic solids. Eg: Ice, dry ice.

c. Atomic solids/Covalent solids: Solids which are composed of atoms joined by a network. Eg: Diamond.

d. Metallic solids: Solids comprised of metal ions held together by electron cloud. This is called as the electron sea model. Eg: Na

Alloys: Alloys are homogenous mixtures of two or more metals . They are classified into two types namely:

a. Substitutional alloys - Eg: Brass (Mixture of Cu and Zn)

b. Interstitial alloys - Eg: Steel (Mixture of Ca nd Fe)

Comparison of Some Important Characteristics of Solids and Liquids

1. Solids are rigid and non-compressible while liquids can be compressed.

2. Solids do not flow whereas liquids do.

3. Solids have high density while liquids have low density than solids.

INTER CONVERSION OF THE STATE OF MATTER

Changing temperature, pressure or both can change matter from one physical state to another.

1.Changing a solid to a liquid is called melting.

2.Changing a liquid to solid is called solidification.

3.Changing a liquid to gas is called vaporization.

4.Changing a gas to liquid is called condensation.

5.Changing a solid to gas directly is called sublimation.

6. Changing a gas to solid directly is called deposition.

Temperature remains constant when phase change occurs. The heat given to change the phase is used up in breaking the bonds and not in increasing the temperature.

Increasing or decreasing pressure and temperature changes the states of matter. Increasing pressure and decreasing temperature can convert a gas into a liquid and vice versa.

Evaporation is the phenomenon in which a liquid changes to gaseous state below its boiling point.For evaporation, water molecules at the surface must must have the energy to break apart from the intramolecular forces of attraction and become a gas.

Evaporation causes cooling because heat energy is needed for evaporation to occur. The energy is taken away by the molecules when they convert from liquid into gas thus cooling the object.

Intermolecular forces:

a. Hydrogen bonding: Occurs between molecules having H directly bonded to O,N and F. It is a very strong bond. Eg: H2O

b. Dipole-dipole interaction: Occurs in polar molecules i.e molecules with significant charge separation between the constituent atoms. Eg: HCl

c. London dispersion forces: Occur is non-polar molecules i.e molecules with little or zero charge separation between the constituent atoms. Eg: F₂

Intramolecular forces:

a. Covalent bonding, b. Ionic bonding, c. Metallic bonding