化学计量、产物产率与限量反应物

Measure 50 mL of ethylenediamine using a graduated cylinder and transfer it to a 200-mL volumetric flask. Add deionized water until the solution reaches the calibration line on the flask. Add a magnetic stir bar and mix on a stir plate for one to two minutes until homogeneous. This produces 200 mL of the target solution.

Ethylenediamine is toxic, caustic, flammable, and corrosive, so all work must occur in a fume hood. Wear a lab coat, chemical splash goggles, and gloves as personal protective equipment. Store the prepared solution in a flammables cabinet until needed to prevent exposure and fire hazards.

Each pair of students needs two 10-mL graduated cylinders, beakers of various sizes (100, 400, 600, and 800 mL), a 500-mL filter flask, a Büchner funnel, a glass stirring rod, filter paper, and a rubber policeman. Additional supplies include lab tape, silicone tubing, disposable pipettes, and squeeze bottles of deionized water and acetone.

Transfer the cooled solution to a labeled brown glass dispensing bottle with a 20 mL capacity pump. Store the bottle in a flammables cabinet until use. Proper storage prevents degradation, minimizes exposure hazards, and maintains solution integrity for laboratory experiments.

Label separate waste containers for organic, aqueous, and solid nickel waste according to your institution's disposal procedures. Place labeled containers in an approved waste collection area. This organization ensures proper segregation and safe handling of different waste types generated during the experiment.

A volumetric flask provides precise volume measurement with its calibrated mark, ensuring accurate concentration of the final solution. The narrow neck and flat bottom allow exact filling to the target volume, which is critical for preparing solutions with specific v/v percentages required in stoichiometric calculations.