Aunit of area often used in measuring land areas is the hectare, defined as 104 m2. an open-pit coal mine consumes 75 hectares of land, down to a depth of 26 m, each year. what volume of earth, in cubic kilometers, is removed in this time?

This is what i found on google “according to the collision theory, the following criteria must be met in order for a chemical reaction to occur: molecules must collide with sufficient energy, known as the activation energy, so that chemical bonds can break. molecules must collide with the proper orientation.” i hope this information you.