The chemistry we learn is chemicals wholesale to better serve our lives

chemicals wholesale (1) The use of alcohol lamp should pay attention to the "three Nos" : ① Do not add alcohol to the burning alcohol lamp; ② Light the alcohol lamp from the side with a match, and do not use the burning alcohol lamp to directly light another alcohol lamp; ③ Put out the alcohol lamp should be put out by the lamp cap, do not blow out. (2) The amount of alcohol in the alcohol lamp shall not exceed 2/3 of the volume of the alcohol lamp and shall not be less than 1/4. 

(3) The flame of the alcohol lamp is divided into three layers, external flame, internal flame and flame core. Heat objects with the outer flame of an alcohol lamp. (4) If the alcohol lamp is accidentally overturned when burning, when the alcohol is burning on the test bench, it should be covered with sand in time or put out the flame with a wet rag, and cannot be washed with water. (5) Clamp - iron clamp, tube clamp The position of the tube clamp should be nearly 1/3 of the tube mouth. The long handle of the tube clamp, do not press your thumb on the short handle. When the tube clamp is holding the tube, the tube clamp should be set from the bottom of the tube to the top; The clamping part is about 1/3 away from the mouth of the tube. When holding 

(6) the instrument for separating substances and adding liquid by hand - the funnel and the long-neck funnel - for filtration, the lower end of the funnel should be kept close to the inner wall of the beaker to avoid splashing the filtrate. The lower end of the funnel should be inserted below the liquid level to prevent the generated gas from escaping from the funnel mouth. (1) Storage of drugs: general solid drugs are placed in a wide-mouth bottle, liquid drugs are placed in a small-mouth bottle (a small amount of liquid drugs can be placed in a drop bottle), metal sodium is stored in kerosene, white phosphorus is stored in water 2, the general principle of drug access 1. If the dosage is not specified, the minimum amount should be taken, and the solid should cover the bottom of the test tube, and the liquid should be 1~2mL. The reagent can not be put back into the original bottle, can not be thrown away, can not be taken out of the laboratory, should be placed in the designated container.

② "three noes" : Any drug can not be held by hand, tasted with the tongue, or directly with the nasal smell reagent (if you need to smell the smell of gas, the hand should be gently fanned on the mouth of the bottle, only a very small amount of gas into the nostrils) 3, the use of solid drugs 

①chemicals wholesale powder and granular drugs: medicine spoon or V-shaped paper groove ② Block and strip drugs: 

4, the use of liquid drugs ① liquid reagent pouring method: take off the cap, put it on the table, (so as not to pollute the drug). The label should be toward the palm (to avoid residual liquid flowing down and corroding the label). Pick up the reagent bottle, hold the bottle close to the edge of the tube mouth, slowly pour the reagent, pour the bottle cap, label outward, put back in place. 

② Drop addition of chemicals liquid reagents: The use of droppers: a, first drive out the air in the dropper, and then absorb the reagent b, when dropping the reagent, the dropper should be kept vertically suspended above the mouth of the container and add C. During use, always keep the rubber nipple on the top, so as not to be corroded by the reagent D. After the dropper is used, wash it with water immediately (except the dropper on the drop bottle) e, the plastic head dropper must not reach into the container or contact the wall when used. Otherwise, it will cause reagent pollution (2) Connect the instrument device and the device air tightness inspection device air tightness inspection device: First immerse one end of the catheter in water, close to the outer wall of the container with your hand, stop for a moment, if there are bubbles at the mouth of the catheter, loosen the palm, the water column at the mouth of the catheter rises, stop for a moment, the water column does not fall back, it means that the device does not leak.