CHEMISTRY · Multi-part · CBSE · Chemistry · Is Matter Around Us Pure? · Is Matter Around Us Pure?
Problem
Three laboratory samples are listed below.
• Sample A: Seawater scooped from a tide pool, containing dissolved ions and visible sand grains
• Sample B: Commercial milk that has been diluted 1:1 with deionized water
• Sample C: A 0.20mol L−1 aqueous solution of potassium nitrate
Each sample is poured through a gravity funnel fitted with standard qualitative filter paper (pore diameter ≈10μm).
(a) Classify each sample as a true solution, a colloid, or a suspension. Justify your classifications in terms of particle size and uniformity.
(b) Predict qualitatively what each filtrate will look like immediately after passage through the filter. Provide molecular-level reasoning that connects your predictions to the classifications in part (a).
(c) For any sample(s) for which filtration is ineffective at removing all dispersed or dissolved matter, propose one additional separation technique that would succeed. Explain the underlying property that the new technique exploits.