In the experiment, the filter paper is often used together with the filter funnel, Buchner funnel and other instruments. The filter paper should be folded into a suitable shape before use. The common folding method is to fold the filter paper into a flower like shape. The higher the folding degree of the filter paper, the higher the surface area it can provide and the better the filtering effect. However, pay attention not to over fold the filter paper and cause it to break. Put the drainage glass rod on the multi-layer filter paper, and use even force to avoid the damage of the filter paper.
Operation process
1. Fold the filter paper in half, twice in a row, to form a 90 ° central angle shape.
2. Press three layers of folded filter paper on one side and one layer on the other side to open, forming funnel shape.
3. Put the funnel-shaped filter paper into the funnel. The edge of the filter paper should be lower than the edge of the funnel. Pour some clear water into the funnel mouth to make the soaked filter paper close to the inner wall of the funnel, and then pour out the remaining clear water for use.
4. Place the funnel with the filter paper on the funnel holder for filtration (such as the ring of the iron stand), put the beaker or test tube to receive the filter solution under the funnel neck, and make the tip of the funnel neck lean against the wall of the receiving container.
5. When filling the funnel with the liquid to be filtered, hold the beaker with the liquid in the right hand, and hold the glass rod with the left hand. The lower end of the glass rod is close to the lower side of the funnel, so that the cup mouth is close to the glass rod. When the filtered liquid flows out along the cup mouth, it will flow into the funnel with the inclination of the glass rod. The liquid level in the funnel cannot exceed the height of the filter paper in the funnel.
6. When the liquid passes through the filter paper and flows down the funnel neck, check whether the liquid flows down the wall of the cup and is injected into the bottom of the cup. Otherwise, move the beaker or rotate the funnel so that the tip of the funnel is firmly attached to the wall of the beaker, and the liquid can flow slowly down the inner wall of the beaker.
