Why dont you feel the gravitational force between your hand and pencil? what do you feel

No, you DO feel gravity between your hand and a pencil, cause the weight of the pencil is essentially the gravitational pull. You don't feel it so much because of the relatively insignificant weight of the pencil

I hope I helped you

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.

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.