A student attempts to make a cup of sweetened tea less sugary by pouring the hot liquid through an ordinary coffee-filter cone. After filtration, the tea tastes just as sweet as before.
Answer the following questions about the molecular-level events occurring during this failed separation attempt.
(a) Describe, at the particulate level, the difference between a homogeneous aqueous solution of sucrose and a heterogeneous suspension of insoluble solids.
(b) Typical coffee-filter paper has pore diameters on the order of 5μm. The hydrated diameter of a sucrose molecule in water is approximately 1nm. Explain quantitatively why essentially all sucrose molecules pass through the filter along with the water.
(c) Propose an alternative physical separation method that could remove dissolved sucrose from water without inducing chemical change. Explain the principle behind the method and why it would succeed where filtration fails.