Chengdu Full-time Senior High School Cram School Sharing: Common Error-Prone Operations in Chemistry Experiments (II)

In view of the tutoring needs of students participating in the full-time senior high school cram school in Chengdu, Xiaobian has deliberately sorted out and summarized the following contents, which are only for the reference of participating students:

Common error-prone operations in chemical experiments (2)

Access to medicines

Error point: A. Take powdered drugs, due to the large spoon, when adding drugs, can not go deep into the container to cause spilling or adhering to the inner wall of the container, and do not know to use a V-shaped paper tank instead of a spoon to send drugs into the container. B. When dumping liquid drugs, the mouth of the reagent bottle is not close to the receiver mouth, causing the drug to flow out, and the label is not to the palm of the hand, resulting in the label being corroded.

Correct Method: A. Take a powdered or fine-grained solid, usually with a spoon or paper trough. When operating, do "one send, two vertical, three bullets". (That is, the medicine is fed flat into the bottom of the test tube, the test tube is erected, and the finger is light ammunition spoon handle or paper slot.) ) so that the drug all fall to the bottom of the test tube. B. The use of bulk or large particle-like solids is commonly used in forceps, and the operation essentials are "one horizontal, two put, three slow vertical." "That is, when adding a block of drugs to the test tube, the test tube should be placed horizontally, and after the drug is placed in the test tube mouth, the test tube is slowly erected so that the drug slowly slides along the tube wall to the bottom of the test tube." C. Use a thin-mouth bottle to dump liquid drugs, and the operation essentials are "one put, two directions, three strokes, and four streams". That is, first take the reagent cork upside down on the table, and then pick up the bottle, the label on the bottle is to the palm of the hand, the bottle mouth is next to the test tube mouth, so that the liquid slowly flows into the bottom of the test tube along the inner wall of the test tube.

The above is from the sharing of Chengdu Meibo Education Xiaobian, thank you for reading.