Powdered calcium oxide is more effective in water than block shaped calcium oxide

The main reasons why powdered calcium oxide reacts faster in water than block shaped calcium oxide are as follows:

1、 Contact area factor

Powdered calcium oxide has a larger specific surface area. Specific surface area refers to the total area per unit mass of material. Powdered calcium oxide particles are small and their total area is much larger than that of block shaped calcium oxide. When reacting with water, a larger contact area means more reaction sites, which can allow more calcium oxide molecules to come into contact with water molecules and react, thereby accelerating the reaction rate.

2、 Diffusion rate factor

For powdered calcium oxide, water molecules can diffuse more rapidly to the surface of the calcium oxide particles and react with them. Due to its large volume, block shaped calcium oxide requires relatively long diffusion paths for water molecules to reach its interior for reaction. The small particles of powdered calcium oxide greatly shorten the diffusion distance of water molecules, increase the diffusion rate, and thus accelerate the progress of the reaction.

3、 Reaction kinetics factors

From the perspective of reaction kinetics, the reaction rate is related to factors such as the concentration of reactants and contact area. Powdered calcium oxide can dissolve faster in water and release calcium ions and hydroxide ions, increasing the concentration of reactants and accelerating the reaction. The dissolution rate of block shaped calcium oxide is relatively slow, which limits the reaction rate.