What is the purpose of the piece of filter paper inside the 400 ml beaker?

The purpose of a filter paper inside a beaker is to retain the suspended solid particles found in the solution.

The retention capacity of the filter paper will depend on the size of the pores of the filter. Thus, for example, if the pores of the filter have a diameter of 1 mm, particles with a diameter greater than 1 mm will be retained, and the rest of the solution will pass through the pores.

The removal of impurities through filters is a physical separation process.

answer: the rate of diffusion increases with increase in temperature.

increase in temperature, increases the molecular/particles speed (kinetic energy. diffusion means movement of particles through the material.

generally, the heavier the particle the more it interacts with the environment and more the temperature matters. so higher temperature results in higher diffusion.