Write the definition of non-periodic change?

Write the definition of periodic change?

Write the definition of entropy.

Write the definition of entropy.

Write the definition of Irreversible change?

Write the definition of Reversible change?

Write the definition of variation.

Write the definition of physical change?

Write the definition of chemical change?

Definition of set

Give the mathematical definition of entropy change. Discuss the relationship between entropy change & spontaneity of a process.