"Separation of Matter" PPT

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"Separation of Matter" PPT

Part One: Crystals and Amorphous

crystal

Crystal characteristics: regular geometric shape, fixed melting point and freezing point

Amorphous

Amorphous characteristics: no regular geometric shape, no fixed melting point and freezing point

How do the composition of the solution change during the production of table salt?

Crystallization: The process in which solid solutes that can no longer be dissolved in a solution are precipitated from the solution in the form of crystals.

Separation of substances PPT, part 2 content: activities:

1. Prepare a cup of saturated copper sulfate solution at 70°C. Use a dropper to suck up 1 drop of the saturated copper sulfate solution and drop it on the concave glass slide, as shown in the picture.

2. Observe carefully (use a magnifying glass or microscope) to see if there are any crystals.

Experiments have shown that crystals can also be obtained by cooling a thermally saturated solution.

Think about it:

Why can crystals be obtained by cooling a hot saturated solution?

Do you think you can get more salt crystals using this method?

The solubility of table salt is not greatly affected by temperature. The maximum amount that can be dissolved in the same solvent does not change much after cooling.

Crystal formation:

Method 1: Evaporate the solvent

Applicable to all saturated solutions and substances whose solubility is less affected by temperature, such as table salt, etc.

Method 2: Cool the hot saturated solution

It is suitable for solid substances whose solubility changes greatly due to temperature, such as potassium nitrate, etc.

Separation of substances PPT, part 3: Apply what you learn

There are many saline-alkali lakes in our country. There is a large amount of sodium chloride and soda ash dissolved in the lake water. Farmers there fish for alkali in winter and dry salt in summer. Use the knowledge you have learned to explain the reason. (The solubility curves of soda ash and sodium chloride are as shown in the figure)

Crystalline Hydrates—Understanding Copper Sulfate

When a small amount of white copper sulfate powder is added to a saturated solution of copper sulfate, the following phenomena may occur: a. Blue crystals precipitate; b. The solute in the saturated solution decreases; c. The solute in the saturated solution increases; d. The solvent in the saturated solution decreases; e. The solvent in the saturated solution increases; f. The total mass of the saturated solution remains unchanged. The correct group of the above judgments is ( )

A.a,b,d B.a,c,e

C. c, d, f D. b, e, f

Separation of substances PPT, part 4 content: practice:

1. The process of forming crystals from a solution is called crystallization. There are usually two methods of crystallization: (1) __________; (2) __________.

2. Cool the saturated solution of potassium nitrate at 80°C to room temperature. The following statement is incorrect ( ).

A. The mass of the solvent remains unchanged. B. The solubility becomes smaller.

C. The mass fraction of the solution remains unchanged. D. Potassium nitrate crystals precipitate.

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"Separation of Matter" PPT courseware:

"Separation of Substances" PPT courseware Part 1: Precipitation method 1. As shown in Figure 1-52, take a cup of mud water and let it sit for 5 minutes to see if any impurities settle at the bottom of the cup. 2. Add a little alum or activated carbon to the mud water, let it sit for 5 minutes, and observe the occurrence of mud water...

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Update Time: 2024-10-02

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