Explain the anomalous expansion of water?

Answer 1

Anomalous expansion of water takes place because when water is heated to 277K hydrogen bonds are formed. Though ice is supposed to expand when it is converted into water, this gradual formation of hydrogen bonds causes it to contract, i.e. the contraction caused due to the formation of hydrogen bonds is greater than the actual expansion of ice. At 277K water has the maximum density because all the hydrogen bonds are formed by 277K beyond which water obeys the kinetic theory of molecules, an increase in volume when heated and the reverse when cooled. The same thing happens in the reverse when water is cooled beyond 277K.

Answer 2

when water at 0'C is heated ,it goes on contracting till it reaches 4'C . After 4'C, it expands when heated as other liquids.this peculiar behaviour of water in temperature range 0'C to 4'C is called anomalous expansion of water.

Answer 3

The usual phenomenon is that as temperature of a liquid is decreased then its volume decreases. Same way as the temperature of water is reduced, say, from 10 deg right to 4 deg its volume decreases. But when the temperature is decreased below 4 deg, instead decrease in its volume an increase in the volume of water takes place and hence its density decreases. This is known as anomalous expansion of water. So the most advantage is that the cooler part will be floating over the hotter portion. Thus even when the temperature falls to negative deg Celsius the lower portion will remain at the same temperature 4 deg and that too in liquid form. The upper portion will be solidified into ice and they simply float over that 4 deg Celsius liquid. This gives an opportunity for the aqua creatures to survive even during winter season. This is the creative intelligence of Nature which is to be appreciated.

Answer 4

Water is a polar molecule, where the centers of positive and negative charge are separated. In an applied electric field, the molecules align with the field. In water, the extensive hydrogen bonded network tends to oppose this alignment, and the degree to which this occurs is measured by the relative permittivity. In water, polarity shifts are rapidly transmitted through shifts in orientation of the linked hydrogen bonds, and therefore water has a high relative permittivity, about 80 at room temperature. This allows water to dissolve salts, as the attractive electric field between ions is reduced by about 80 fold. [1] As the temperature increases, the thermal motion of the molecules disrupts the hydrogen bonding network, and therefore the relative permittivity decreases with temperature, to about 7 at the critical temperature. At 205°C the relative permittivity has fallen to 33, the same as methanol at room temperature. Thus from 100°C to 200°C water behaves like a water / methanol mixture. The disruption of the extended hydrogen bonding is also responsible for much of the anomalous behaviour of superheated water, as extra energy needs to be supplied to break the bonds (increased heat capacity), and the molecules move more freely (viscosity, diffusion and surface tension effects).

Answer 5

It means that when water is cooled below 4 degrees Celsius (277 Kelvin), and when it finally freezes at 0 degrees Celsius (273 Kelvin) it expands; whereas most other substances contract when they are cooled or when they freeze.

Answer 6

water contracts till it reaches the temperature of 4 degree celsius.between 4 and 0 degree Celsius water expands.