States of Matter Test - 8

1 mole of O₂ at STP has mass 32g and volume 22.7L. It contains 6.022 × 10²³ molecules of dioxygen.

A gas which obeys the ideal gas equation, p V = nRT under all conditions of temperature and pressure is called an ‘ideal gas’.
However, there is no gas which obeys the ideal gas equation under all conditions of temperature and pressure. Hence, the concept of ideal gas is only theoretical or hypothetical. The gases are found to obey the gas laws fairly well when the pressure is low or the temperature is high.
Such gases are, therefore, known as ‘real gases’. All gases are real gases. Hence, at high pressure and low temperature, a real gas deviates most from ideal behaviour.

Adding a non-volatile solute like salt, decreases the vapor pressure of water. This is because some of the solute(salt) particles occupy the position of solvent molecules (water)  on the liquid surface. So escaping tendency of molecules (water) is reduced and hence vapour pressure decreases.

While melting (fusion) of a substance the molecules get separated to some extent but when the same substance is vaporised  the molecules get separated to a greater extent which requires more enery, i.e. more heat.

The polarizability in isotropic media is defined as the ratio of the induced dipole moment of an atom to the electric field that produces this dipole moment.

Surface tension results because a liquid tends to minimize the number of molecules at the surface (i.e to minimize the surface area )

Capillarity action results because intermolecular forces within the liquid (cohesive forces) and those between the liquid and the tube walls (adhesive forces). Generally,Capillary action occurs when the adhesion to the walls is stronger than the cohesive forces between the liquid molecules.