"Method of Separating Salt and Water" Dissolution PPT Download

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"Method of Separating Salt and Water" Dissolution PPT Download

Part 1: Do salt and water evaporate together?

Experimental purpose: to verify whether salt and water evaporate together.

Experimental materials: 1 cup of concentrated salt water, 1 cup of clean water.

Experimental steps: (1) Dissolve the salt at the bottom of the cup. Observe the concentrated salt water collected in the previous experiment. There is still undissolved salt at the bottom of the cup. Use a pen to mark the level of concentrated salt water on the wall of the cup, and then add water little by little until all the salt in the cup is dissolved.

(2) Evaporate the water in the cup. Place the cup on the windowsill to let the water evaporate. When the water level in the cup drops to its original level, what will happen to the dissolved salt?

Table salt that has been dissolved will reappear.

What is the conclusion of the experiment?

Experimental conclusion: The change of salt dissolution in water is a reversible process. Salt can be dissolved in water and can also be separated from water. The salt dissolved in water can be separated by evaporation.

How to prove it experimentally?

Precautions when using evaporating dishes

(1) Do not cool quickly after heating to prevent rupture.

(2) After heating, it cannot be placed directly on the experimental table. It should be placed on an asbestos net to avoid burning the experimental table.

(3) When the amount of liquid is large, it can be heated directly. If the amount is small or the liquid is viscous, it should be heated with an asbestos net or placed on a mud triangle.

(4) When heating the evaporating dish, stir it continuously with a glass rod to prevent the liquid from being locally heated and splashing around.

(5) After heating, you need to use crucible pliers to move the evaporating dish.

(6) After a large amount of solids precipitate, extinguish the alcohol lamp and use residual heat to evaporate the remaining water.

(7) When heating, you should first preheat with a small fire, and then increase the heat with a high fire.

(8) Use preheated crucible tongs to pick up the hot evaporating dish.

(9) The solution in the evaporating dish does not exceed two-thirds of its volume.

Method for separating salt and water PPT, Part 2: White particles in the evaporating dish

1. Learn to use an alcohol lamp

(1) Understand the alcohol lamp

An alcohol lamp is a heating tool that uses alcohol as fuel and is used to heat objects. An alcohol lamp consists of a lamp cap, a bottle stopper, a wick, alcohol and a glass bottle.

(2) The flame of the alcohol lamp

The flame of the alcohol lamp is divided into three layers. The outermost layer is called the outer flame, the middle layer is called the inner flame, and the innermost layer is called the flame core. The temperature of the outer flame is the highest, followed by the inner flame, and the temperature of the center of the flame is the lowest.

(3) How to use alcohol lamp

Step 1: Hold the lamp pot with your left hand and open the lamp cap with your right hand.

Step 2: Use a match to light the alcohol lamp (bottom up).

Step 3: Use outer flame for heating (the outer flame has the highest temperature)

Step 4: Cover the lamp cap and extinguish the alcohol lamp (cover it twice)

(4) How to extinguish the alcohol lamp

When it is necessary to turn off the flame after heating, the lamp cap can be used to put it out. After the lid is put out, it needs to be re-covered to prevent the lamp cap from being unable to open during future use. It is absolutely prohibited to blow out the flame with your mouth to avoid causing the alcohol in the lamp to burn and explode.

2. Experiment on heating and evaporating concentrated salt water

Experimental materials: alcohol lamp, tripod, asbestos net, evaporating dish, concentrated salt water, magnifying glass

Experimental steps:

1. Put an appropriate amount of water in the beaker, then put the salt into the water and stir until all the salt is dissolved.

2. Pour 10 ml of salt water into the evaporating dish. Place the evaporating dish on the asbestos mesh of a tripod and heat it using an alcohol lamp.

3. Grill and roast repeatedly. Extinguish the alcohol lamp before the salt water has completely evaporated.

4. Use a magnifying glass to observe the white particles in the evaporating dish, compare them with the salt particles used in the dissolution experiment, and make records.

PPT on how to separate salt and water, Part 3: Classroom questions

1. Fill in the blanks

1. The flame of the alcohol lamp is divided into three layers. The outermost layer is called ________, the middle layer is called ________, and the innermost layer is called ________.

2. The temperature of the outer flame is the most ________, the temperature of the inner flame is ________, and the temperature of the flame center is the most ________.

3. Salt dissolved in water can be separated by ________ method. This method is widely used in daily life.

4. The dissolution of salt into water is a _________ process.

2. Multiple choice questions

1. The process of precipitation of an object from a solution is called ( )

A dissolve B crystallize C evaporate

2. The method ( ) can be used to separate salt and water.

A Sun drying B Add hot water C Stirring

3. There is undissolved salt at the bottom of a cup of concentrated salt water. We can ( ) dissolve the salt.

A Stir continuously B Add water to the cup C Evaporate the water in the cup.

PPT on how to separate salt and water, Part 4: Class summary

1. The change of salt dissolution in water is a reversible process. Salt can be dissolved in water and can also be separated from water. The salt dissolved in water can be separated by evaporation.

2. The flame of the alcohol lamp is divided into three layers. The outermost layer is called the outer flame, the middle layer is called the inner flame, and the innermost layer is called the flame core. The temperature of the outer flame is the highest, followed by the inner flame, and the temperature of the center of the flame is the lowest.

Keywords: Free download of Chinese PPT courseware for the first volume of the fourth grade of the textbook version, PPT download of the method of separating salt and water, PPT download of dissolution, .PPT format;

For more information about the PPT courseware "Methods to Dissolve and Separate Salt and Water", please click the "Methods to Dissolve and Separate Salt and Water" ppt tag.

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Update Time: 2024-11-20

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