Chapter 17, Problem 9A

Interpretation Introduction

Interpretation: The reason due to which pouring grain into silos is potentially active process needs to be explained using the collision theory.

Concept introduction:Collision theory helps to explain qualitatively the relation between chemical reactions and the rates at which they occur.

It mainly consists of the points,

• In order to react there must be a collision between the molecules.
• Collisions must be sufficiently energetic to break chemical bonds. The minimum threshold energy required to bring out the reaction is called the activation energy.
• As the temperature increases, molecules collide more vigorously, increases the chances of breaking the bonds which results in chemical reaction.

Answer to Problem 9A

Tiny size of the grain creates a big surface area which on being exposed to heat or air can cause explosion.

Explanation of Solution

Grain dust has very large surface area because it consists of very small particles. While loading the grain in silos grain dust particles collide with each other. If there is an ignition source or any spark of static electricity, it provides the grain enough activation energy to bring out a combustible reaction. Since there are large number of grain dusts having high surface area, a chain reaction initiates which causes explosion. The oxygen in the air further intensifies the combustion.

Conclusion

Tiny size of the grain creates a big surface area which on being exposed to heat or air can cause explosion.