First, the experimental report:

Experimental contents and steps

Practice record

1. Weigh and dissolve the original salt.

(1) Put a piece of paper of the same quality on each of the two paper trays of the paper tray balance. Observe the zero point and weigh 5g of raw salt.

The solid crude salt is _ _ _ _ _ _ _ _ color.

(2) Measure 10ml of water with a measuring cylinder and pour it into a beaker. Take a spoonful of raw salt with a medicine spoon and add it to water, and stir until it no longer dissolves. Weigh the remaining raw salt with a tray balance.

10ml water can dissolve _ _ _ _ _ _ g crude salt.

filter

Use a funnel, filter bucket and filter paper as a filter to filter crude salt. If the filtrate is turbid, it should be filtered again.

The filtrate is _ _ _ _ _ _ _ _ colored liquid.

evaporate

Pour the clarified filtrate into an evaporating dish, put it on an iron ring, heat it with an alcohol lamp, stir it with a glass rod while heating, and stop heating when a large number of crystals appear.

The amount of filtrate in the evaporating dish is gradually _ _ _ _ _. When water evaporates to a certain extent, _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

transfer

Transfer the solids in the evaporating dish to a clean container with a glass rod.

Crude salt purification step

1. Dissolve

Weigh 5.0 g of raw salt with a tray balance, gradually add the raw salt into a beaker containing 10 mL of water with a medicine spoon, and stir with a glass rod while adding it until the raw salt is no longer dissolved. Observe whether the obtained salt solution is turbid. Weigh out the remaining crude salt and calculate how many grams of crude salt are dissolved in 10 ml of water.

Weighing raw salt/gram

Residual crude salt/g

Dissolved crude salt/g

5.0

filter

Observe the color of residue and filtrate on the filter paper carefully. If the filtrate is still turbid, it should be filtered again.

If the filtrate is still turbid after two times of filtration, how to check the experimental device and find out the reason?

evaporate

Pour the obtained clear filtrate into an evaporating dish. Put the evaporating dish on the iron ring of the iron frame, heat it with alcohol lamp, and stir it constantly with glass rod. When more solids appear in the evaporating dish, stop heating. The waste heat of the evaporating dish is used to evaporate the filtrate.

Step 4 calculate the output

Transfer the solid to the paper with a glass rod, weigh it and recycle it to the container designated by the teacher. The purified sodium chloride is compared with the original salt, and the yield of refined salt is calculated.