PERPERTIES OF CERAMICS, USES OF CERAMICS, USES OF METALS, USE OF ALUMINUM AND ITS ALLOYS, CERAMICS, COMPOSITION OF CERAMICS, FINITE (Limited) RESOURCES OF MATERIALS AND THE IMPORTANCE OF RECYCLING
VAPOUR PRESSURE: When a liquid is kept in a closed container some of the molecules evaporate and some vapours collide with the liquid and return back into liquid which is called condensation. Initially the rate of evaporation is greater than the rate of condensation. As the number of molecules in the vapour phase increases the rate of condensation also increases. Ultimately at a given temperature a state will be reached where the rate of evaporation is equal to the rate of condensation. The system is then said to be at equilibrium. At this stage the pressure exerted by vapours on the walls of container is called vapour pressure. Since the number of molecules with higher energy increases with temperature hence, the rate of evaporation also increases. Thus vapour pressure increases with the increase in temperature. SOLIDS: In solids particles are closely packed. Th...