What is the method used to prove the presence of trace amounts of water in the alcohol in the alcoho

The one on the first floor is not right, but after the combustion of alcohol, it also produces water, so how can it be proved that there is water in the first place?

Anhydrous copper sulphate (colorless) can be added to the alcohol being tested, and if it turns blue, it means that there is water present in the alcohol being tested.

Anhydrous copper sulphate is best.

The 2nd floor is also not quite right, and when there is too little water in the alcohol, distillation cannot be separated.

With anhydrous copper sulfate, what if you can't see the color change if you are color blind? Throw in sodium.

Take a small amount of alcohol to be tested, add anhydrous copper sulfate, if blue appears, there is water.

We should know that if we put the liquor (with an alcohol concentration of 40 to 50 percent) in a high-temperature resistant cup and ignite it with fire (alcohol can burn), we can first find that it is burning, and then slowly extinguish, leaving a lot of liquid at the bottom of the cup, and then add copper sulfate reagent, and find that it turns blue, which proves that there is water

The boiling point of alcohol is more than 80 degrees, and the boiling point of water is 100 degrees, so as long as you want to distill it, you can separate water from alcohol

Upstairs the answer is incorrect

Anhydrous copper sulphate, official answer!!

Take a small amount of alcohol and light it, then quickly cover it with a cup, and after burning, if there are small droplets of water on the wall of the cup, it is proof that there is water.

You still have a piece of sodium, and if there is water it reflects bubbling.

The effect of anhydrous copper sulphate produced by trace amounts of water is not obvious.

Anhydrous copper sulphate, observe if the color changes. Just go in and just go in, what the teacher said, the standard answer on the exam paper.

Anhydrous copper sulphate is seen to contain anhydrous or not.

Answer: The alcohol in the alcohol lamp cannot be less than 1 4 and not more than 2 3; Because; When the alcohol lamp is less than 1 4, the mixture of air and alcohol in it is easy to produce **, and when it is more than two-thirds, the alcohol is easy to overflow, igniting the whole bottle of alcohol.

Distilled water is pure.

That's what our teacher said.

1) Use a funnel to add alcohol to the alcohol lamp;

2) Remove the hot evaporation dish with crucible slag bright pliers;

3) The fine mouth is used to store liquid reagents;

4) Take 15 ml of water and use a graduated cylinder and a rubber tip dropper Therefore, the answer is: (1) c; （2）h；（3）e；（4）ad．

1. Alcohol lamp is a very frequently used experimental equipment in middle school experiments, generally using 95 alcohol as fuel. 2. Alcohol lamp is a heating tool fueled by alcohol, which is widely used in laboratories, factories, medical treatment, scientific research, etc. Since it does not produce smoke during combustion, it can also be sterilized by burning the instrument by Qiaowang.

Due to the heat generated during the combustion of the alcohol lamp, it can be used to imitate the material for other experiments. Its heating temperature reaches 400-1000 or more.

Take off the cap, lift the wick upwards and add alcohol to the alcohol lamp with a funnel. The amount of alcohol should not be held over the volume of the excess alcohol lamp 2 3, nor less than 1 3 must be used with a funnel.

Please be safe when adding alcohol!

Encyclopedia on.

Let me add one: edible nature: if you drink too much, you will get drunk, and if you drink too much, you will hang up.

1) The use of alcohol lamps should pay attention to the "three nos": do not add alcohol to the burning alcohol lamp; Use a lit match to light the alcohol lamp from the side, not a lit alcohol lamp to light another alcohol lamp directly; The alcohol lamp should be extinguished with the lamp cap cap, not blown out.

2) The amount of alcohol in the alcohol lamp should not exceed 2 3 of the volume of the alcohol lamp, and it should not be less than 1 3 1 4

3) The flame of the alcohol lamp is divided into three layers, the outer flame, the inner flame, and the flame center. The outer flame temperature is the highest, and the core flame temperature is the lowest. The object is heated with the outer flame of an alcohol lamp. When heating glass instruments are destroyed by hand (such as test tubes), they should be preheated first and then heated.

4) If the alcohol lamp accidentally overturns when burning, and the alcohol burns on the test bench, it should be extinguished with a wet rag or covered with sand in time to extinguish the flame, and it can be flushed with water if it is not ready.

The alcohol used in the alcohol lamp can be lit, generally above 60% (V v), and absolute ethanol can also be used if needed. Industrial alcohol and civil alcohol (if there is such a name) or medical alcohol have no effect on the use of alcohol lamps, and impurities such as methanol in industrial alcohol also produce carbon dioxide and water after combustion, which is harmless to the human body.

Try to choose 95 alcohol for burning, because it is not good to have too low concentration. The alcohol is called anhydrous alcohol. Uses in Biology:

The pigment in chloroplast can be in organic solvent absolute ethanol (or acetone), so the pigment in chloroplast can be extracted with absolute ethanol; Industrial ethanol is 95%. 95% alcohol is used to wipe UV lamps. This alcohol is commonly used in hospitals, but in the home it is only used for the cleaning of camera lenses.

70% 75% alcohol is used for disinfection. This is because too much alcohol will form a protective film on the surface of the bacteria, preventing it from entering the bacteria, making it difficult to kill the bacteria completely. If the alcohol concentration is too low, it can enter the bacteria, but it cannot coagulate the proteins in the body, and it cannot completely kill the bacteria.

Of these, 75% of alcohol disinfection is the best.

New lamps or old lamp pots with less than their volume of alcohol 1 2 should be added alcoholQ: Why? Is it because of the fear that the alcohol will be less than 1 4 during the heating process?

A: Not true. When the alcohol in the alcohol lamp is less than 1 5 of the volume of the alcohol lamp, it is enough to add additional alcohol. This is done to prevent a large amount of alcohol vapor from appearing in the alcohol lamp, and a misfire occurs after the alcohol lamp is lit.

For old lamps, especially lamps that have not been used for a long time, after removing the lamp cap, the wick porcelain sleeve should be lifted and gently blown into the lamp with an ear wash ball or mouth to expel the alcohol vapor that has accumulated in it.

Q: What happens if you don't? Is it because you are afraid of backfire?

Answer: I am afraid that when it ignites, the alcohol vapor in the etc. will ignite at the same time, which will cause danger.

Check the wall of the bottle for damage, and replace it immediately if it is damaged.

Q: What happens if I don't replace it? Is it because you are afraid of alcohol spillage?

Answer: When the alcohol lamp is heated with an alcohol lamp, the alcohol lamp itself will also be heated, which will increase the crack at the damaged place, and the alcohol vapor will overflow from the gap, causing a fire.

The wick should not be too short, — it should be 4-5cm longer after immersion in alcoholAsk: Why is this?

A: The aim is to be able to keep the alcohol safe as it rises along the wick.

Before heating, wipe the wall of the alcohol lamp bottle with a dry rag.

Q: Why is that? Is it the same as the principle of wiping the wall of the test tube clean when heating?

A: The two are similar.

It's all about safety.

It's all the same consequence, and it's easy to cause disaster.

Characteristics, colorless, flammable and explosive. Proportionally, the ratio of ethanol to water should be 3:1 (75 concentrations); Or Nianfeng water plus a little less, anyway, not less than 75 concentration, or 100 should also work.

1) The use of alcohol lamps should pay attention to the "three nos": do not add envy alcohol to the burning alcohol lamp; Use a lit match to light the alcohol lamp from the side, not a lit alcohol lamp to light another alcohol lamp directly; The alcohol lamp should be extinguished with the lamp cap cap, not blown out.

2) The amount of alcohol in the alcohol lamp should not exceed 2 3 of the volume of the alcohol lamp, nor should it be less than 1 3 1 4.

3) The flame of the alcohol lamp is divided into three layers, the outer flame, the inner flame, and the flame heart. The outer flame temperature is the highest, and the core flame temperature is the lowest. The object is heated with the outer flame of an alcohol lamp. When heating glass instruments (e.g., test tubes), preheat first, and then heat.

4) If the alcohol lamp accidentally overturns when burning, and the alcohol burns on the test bench, it should be extinguished with a wet rag or covered with sand in time to extinguish the flame, and it should not be washed with water.

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