Questions

Historians divide the ancient history of Egypt into three periods. the Old Kingdom, the Middle Kingdom and the New Kingdom. The Old Kingdom is called the Age of the Pyramids.

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.

German Silver is an alloy of copper, nickel and zinc. It is composed of 60% copper, 20% nickel and 20% zinc. Due to its white-silverish appearance it is named as german silver but it contains no silver in it.

A protein is being assembled when RNA is being translated. This process goes as, by the process of transcription first DNA is is converted to mRNA. And then by the process of translation this mRNA is converted to proteins.

=> DNA ----> mRNA ----> Proteins.

The device which is used to measure air pressure is called as barometer. If the barometer reading is rising, it indicates that the air pressure is increasing and if the reading is falling the air pressure is decreaing.

SCSI - Small computer systems interface is a type of interface used for computer components such as hard drives, optical drives, scanners and tape drives. It is a competing technology to standard IDE (Integrated Drive Electronics).

Protein synthesis take place in the cytoplasm where ribosomes are located as they are the machinery which are responsible for the protein synthesis.