Why is it suggested you use weighing paper or a watch glass instead of filter paper on
which to allow a sample to dry? Please give two examples.
Some reagents adhere to the filter paper.
It is suggested to use weighing paper or a watch glass instead of filter paper for drying a sample for the following reasons:
1. Non-absorbent nature: Weighing paper and watch glass are generally non-absorbent materials, meaning they do not readily absorb moisture from the sample. This allows for more efficient drying as the sample can freely lose moisture without being trapped or absorbed by the material itself. In contrast, filter paper is designed to absorb liquids, so it may retain moisture from the sample and hinder the drying process.
2. Minimized loss: Weighing paper and watch glass provide a more secure environment for drying delicate or small samples, helping to minimize sample loss. Filter paper can be porous and may allow small particles or fine powders to be lost or dispersed during the drying process. In contrast, weighing paper and watch glass offer a flat surface with minimal openings, reducing the risk of losing valuable or fragile samples.
Example 1: Drying a powdered substance: If you have a powdered substance that needs to be dried, using filter paper may result in the particles getting stuck in the fibers, making it difficult to recover the entire sample. Weighing paper or a watch glass would be a better choice as they ensure easy retrieval of the powder without any loss.
Example 2: Drying a liquid solution: When drying a liquid solution, filter paper can absorb some of the solvent, reducing the amount of recovered sample and potentially altering its concentration. In this case, weighing paper or a watch glass would be preferable as they don't absorb the liquid, allowing for more accurate measurements after drying.
Overall, weighing paper or a watch glass offer better reliability and accuracy in the drying process, minimizing sample loss and ensuring the integrity of the dried sample.