Which word means a process in which some substances change into different substances?

a) compounding
b) physical reaction
c) chemical reaction
d) separation

chemical reaction

Explanation:

it changes the chemical bonds of the substance, turning it into a different substance

Chemical Reaction means a process in which some substances change into different substances

Explanation:

In a chemical reaction, the substance (reactants) undergoes a change from one substance to other different substances known as the products. The products and reactants in a chemical reactions are either compounds or chemical elements.  

A chemical reaction occurs at a specific reaction rate at a chemical concentration and at given temperature. These chemical reactions can be represented in a chemical equation.There are  many kinds of chemical reactions like combustion, decomposition,oxidation, reduction,precipitation etc.,

answer

i think the answer is a) as air pressure in an area increases, the density of the gas particles in that area decreases.

hope it

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).