A. Give two characteristic properties of a liquid.

B. Why does our palm feel cold when we put alcohol or perfume on it?


C. Give two factors which determine the rate of diffusion of a liquid in another liquid.

A. The particles of liquid have the ability to flow. The particles are loosely packed and can move from one place to another. This property is called fluidity.


Liquids have the ability to acquire the shape of the container in which it is kept in. This is possible because of the fluidity of liquids.


B. When alcohol or perfume is put on our palm, the particles of alcohol/perfume gain energy from our palm or surroundings and evaporate. This produces a cooling effect to the palm. The principle behind this is evaporative cooling.


C. The rate of diffusion of a liquid in another liquid is affected by:


(1) Viscosity and chemical nature:


Viscosity is the resistance offered to the flow of liquids, or simply it is the thickness of the liquid. The rate of diffusion also depends upon the chemical nature of the liquids.


(2) Temperature:


An increase in temperature would increase the kinetic energy of the liquid particles which increases the rate of diffusion between them.


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