Questions

Ireland

This is a layer of atmosphere about 60 to 70 km above the earth and extends to about 400km. It contains ionised particles which can reflect radio waves making radio communication round the world possible.

The four bonds of carbon tetrachloride (CCl4) are polar, but the molecule is nonpolar because the bond polarity is cancelled by the symmetric tetrahedral shape. Hence, making the net dipole as zero and molecule as non-polar.

When other atoms substitute for some of the Cl atoms, the symmetry is broken and the molecule becomes polar.

Simple covalent compounds are generally named by using prefixes metal name + nonmetal name + suffix –ide to indicate how many atoms of each element are shown in the formula. Also, the ending of the last (most negative) element is changed to -ide. The prefixes used are mono-, di-, tri-, tetra-, penta-, hexa-, and so forth.

A manometer is used to measure a pressure difference between two points.