Which of the following colloidal systems has the largest surface area per unit mass?
A colloid with particles of diameter 1 nm.
A colloid with particles of diameter 100 nm.
A colloid with particles of diameter 500 nm.
A colloid with particles of diameter 1000 nm.
Colloidal particles have an enormous surface area per unit mass as a result of their small size. A cube with a side length of 1 cm has a total surface area of 6 cm2, but if it were divided into equally sized cubes with a diameter of 1 nm, the total surface area would be 6 m2. Therefore, the colloid with the smallest particle size (i.e., the diameter of 1 nm) will have the largest surface area per unit mass