What is the name of the process in which the chemical structure of rock is altered when it combines with water molecules to form new compounds?

Weathering

Explanation:

when carbon iv oxide from air mixes with water or moisture it forms carbonic acid . The equation is shown below.

H2O + CO2 ⇒ H2CO3

This weak acid react with rock material and changes its chemical structure by dissolving it

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.