GATE Questions

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Land breezes are more common during winter and fall season. It occurs as it becomes night, the air on the land colls fast and air on the water surface are warmth than that and begin to rise.

The place where the river meets the sea or ocean is called as Estuary.

Any properties that are dependent on the amount of matter are called as extensive properties of matter.

Examples are :: Mass, Volume, Density (M/V),...

Polarity :: 

The polarity of a molecule defines its other physical properties such as melting point, boiling point, surface tension, vapor pressure etc... Simply, polarity occurs when the electron distribution in a molecule is asymmetric. This results in a net dipole moment in the molecule. One end of the molecule is charged negative while the other gets a positive charge.

The polarization of a molecule greatly depends on the shape of the molecule. A diatomic molecule like HF mentioned above has no issue of shape. The net dipole moment is only due to the uneven distribution of electrons between the two atoms. However, when there are more than two atoms involved in making a bond, there are many complexities.

The water molecule is of bent shape. Therefore, when the two pair of electrons shared by oxygen with two hydrogen atoms is pulled towards oxygen, the net dipole moment results in the direction of the oxygen atom. There is no other force to cancel out the resultant dipole moment. Hence, the water molecule is highly polar.

Ammonia molecule is of a pyramid shape and the electronegative N atom pulls the electrons towards itself. The three N-H bonds are not in the same plane; hence the dipole moments created do not get canceled out. This makes ammonia a polar molecule.

However, the dipole moments sometimes get canceled due to the shape of the molecules, making the molecule non-polar. Carbon dioxide is such a molecule.

Rayon is a versatile fiber. Rayon is chemically Cellulose. It is widely claimed to have the same comfort properties as natural fibers, although the drape and slipperiness of rayon textiles are often more like nylon. It can imitate the feel and texture of silk, wool, cotton and linen. The fibers are easily dyed in a wide range of colors.

We know that most of the metals are goof conductors of electricity and heat. Metals are very strong but they are malleable i.e, they can be bent into a shape. These are shiny when they are cut or polished. 

Hence, metals are malleable, conductors and luster. All the above are properties of the metals.

Sound waves cannot be transmitted through vacuum.