Which factor explains why a cube of sugar placed in water will dissolve at a slower rate than granular sugar over time?
a
The particles in the cube have more movement.
b
The temperature of the cube decreases.
c
The mass of the cube decreases.
d
The cube has a smaller surface area.
d
The cube has a smaller surface area.
d
The cube has a smaller surface area.
The correct answer is d) The cube has a smaller surface area.
Explanation: When a substance dissolves in a liquid, it does so at the surface of the solid. With a cube of sugar, the surface area in contact with the water is relatively small compared to granular sugar.
To understand why the surface area affects the rate of dissolution, it is important to know that the dissolution process occurs through the collisions between the solute particles (sugar molecules) and the solvent particles (water molecules).
In the case of a cube, only the outer layer of sugar molecules is exposed to the water, resulting in limited contact between the solid and the liquid. This reduces the number of collisions between the sugar particles and the water molecules, slowing down the rate of dissolution.
On the other hand, granular sugar has a larger surface area due to its smaller, irregularly shaped particles. This allows for more extensive contact between the sugar and the water, increasing the number of collisions and leading to a faster rate of dissolution.
Therefore, the smaller surface area of the cube of sugar is the key factor that explains why it dissolves at a slower rate compared to granular sugar over time.