Experimental Activity 8 Removal of Insoluble Impurities in Coarse Salt

Experimental Activity 8

Removal of Insoluble Impurities in Coarse Salt

Purpose

1.Experience the experimental process of preliminary purification of solid mixture.

2.Learn evaporation operation skills, consolidate dissolution and filtration operation skills.

Experimental Supplies

Beaker, glass rod, evaporating dish, crucible tongs, alcohol lamp, funnel, medicine spoon, measuring cylinder (10mL), iron stand (with iron ring), tray balance, filter paper, matches.

kosher salt.

Experimental steps

1. dissolve

5.0 g of coarse salt with a tray balance , gradually add the coarse salt into a beaker filled with 10 mL of water with a medicine spoon, and stir with a glass rod while adding (what does it do?), until the coarse salt is no longer dissolved . Observe whether the obtained salt water is turbid.

Weigh the remaining coarse salt and calculate how many grams of coarse salt are dissolved in 10 mL of water.

2,filter

As shown in Figure 11-13 , filter the saline solution. Carefully observe the color of the residue on the filter paper and the filtrate.

3.evaporation

Pour the resulting clear filtrate into an evaporating dish. As shown in Figure 11-14 , heat with an alcohol lamp.

During the heating process, keep stirring with a glass rod to prevent droplets from splashing due to excessive local temperature. When more solids appear in the evaporating dish, turn off the heat. Evaporate the filtrate to dryness using the residual heat of the evaporating dish. Observe the appearance of table salt in the evaporating dish.

4. Calculation of Yield

Use a glass rod to transfer the solid to the paper, weigh it, and recycle it into a container designated by the teacher. Compare the purified sodium chloride with coarse salt and calculate the yield of refined salt.