Physical issues distinguish between a mixture of water and alcohol and water

Here's an example of a topic.

1. In order to separate water and alcohol from the mixture of alcohol and water, Xiao Ming relied on.

What has been learned, a solution is proposed. Water and alcohol can be separated depending on the freezing point of the water and alcohol. To do this, he used the freezer compartment of the refrigerator at home to do the following experiments:

He placed a mixture of water and alcohol in different proportions in the freezer and used a thermometer to measure the temperature of the mixture. The following table shows the data and observed phenomena

Alcohol ml water ml

Alcohol mixture.

Observe the phenomenon.

8 No coagulation found.

8 No coagulation found.

8 The mixture begins to solidify, and the alcohol does not separate from the water.

6 The mixture begins to solidify, and the alcohol does not separate from the water.

4 The mixture begins to solidify, and the alcohol does not separate from the water.

The minimum temperature of the freezer compartment of the refrigerator is -8).

Please take a closer look at the data in the table and the recorded phenomena, can Xiao Ming separate water and alcohol from the mixture?

What is the effect of adding alcohol to water on the freezing point of water?

How does this conclusion apply in practice?

1. Xiao Ming should not separate water and alcohol from the mixture.

2. Adding alcohol to water can reduce the freezing point of water.

3. This conclusion In actual life, under low temperature conditions in winter, alcohol can be added to the water to improve frost resistance, such as the cooling circulating water in the car water tank, alcohol can be added to it as antifreeze, so that the circulating water will not freeze because of the low temperature at night in winter.

Put the water-alcohol mixture, and put the water in the refrigerator at the same time to condense into ice for water, and not condensed into ice for the mixture of water and alcohol. This is because the condensation point of the mixture of water and alcohol is lower than that of water.

Put it in the refrigerator and freeze it, and the water is frozen into ice before the mixture...

Physical properties: 1. Alcohol has a special smell, and water has no smell.

2. The density of water is greater than that of alcohol, and it can be weighed with the same volume of liquid, and the smaller mass is alcohol.

Chemical properties: 1. Alcohol can be burned, but water cannot.

2. Add iodine, the aqueous solution of iodine is blue, and the alcohol solution of iodine is yellow.

Physical properties: Smell it, alcohol has a smell, water has no smell.

Heat separately and the alcohol boils before the water.

Chemical properties: Take a small amount of sample, ignite, alcohol is flammable, water cannot be burned.

From pH analysis to much more.

Physical properties: The density of water is 1 Alcohol density Water is colorless, odorless and not volatile, and alcohol is colorless and spicy and volatile.

Chemical Properties: Water does not burn Alcohol is combustible.

Physical properties: The density of water at room temperature is 1000 kg cubic meters, and the density of alcohol is 800 kg cubic meters.

Chemical properties: Water is generally non-flammable and does not help burn, but when alcohol is burned, it emits a light blue flame that is not easy to see, which releases heat and produces carbon dioxide and water after combustion.

Physical properties: odor volatile density.

Chemical Properties: Flammable.

Physical properties distinguish between water and alcohol: smell, alcohol with a special fragrance, water without odor.

Chemical properties distinguish between water and alcohol: use a small cotton ball to ferment a small amount of liquid to be tested, ignite, can burn is alcohol, no phenomenon is water.

The physical method can be considered in terms of density, and the density of water is greater than that of alcohol.

The chemical aspect can start with odor, flammability.

Physical methods. 1.Smell, the smell of alcohol is alcohol, and the odorless is water.

2.Put a drop of alcohol and a drop of water on the table, and the alcohol will evaporate quickly.

Chemical methods. 1.Try to ignite two liquids, the one that ignites alcohol and the one that doesn't ignite water.

2.Anhydrous copper sulfate is added separately, and what turns blue is water, and what does not turn blue is anhydrous alcohol.

1.Take a small amount and ignite.

2.Take the same amount and weigh it, the heavy is the water.

3.Smell the smell. Wait.

Physical methods. Smell, the smell of alcohol is alcohol, and the odorless is water.

Chemical methods. Try to ignite two liquids, the one that ignites alcohol and the one that doesn't ignite water.

Smell the smell. Ignite two liquids.

Hydrogen bonds can be formed between water molecules and ethanol molecules in alcohol, which enhances the binding force between molecules and greatly increases solubility. From the molecular structure, it can be seen that both water molecules and ethanol molecules contain hydroxyl groups (-OH), which have similar structures, and they are both polar molecules. According to the principle of similarity compatibility, substances with the same structure or the same properties are easily soluble in each other, polar substances are easily soluble in polar solvents, and non-polar dismantling liquid substances are easily soluble in non-polar solvents.

As a result, water and alcohol are soluble in each other and in any proportion. Due to the voids between the molecules, the volume of water and alcohol when mixed is less than the sum of their respective volumes.

In addition to alcohol (the main component is ethanol), methanol, propanol, ethylene glycol, propylated glycol (glycerol), formic acid, acetic acid, propionic acid, ether, acetone and other organic solvents are miscible with water.

When alcohol and water are mixed, the resulting solution is called an (alcohol) solution.

After mixing salt and water, the resulting solution is called (Shifenghe salt or sodium chloride).

After iodine and alcohol are mixed, the resulting mu is called (iodine wine) solution.

When iodine and water are mixed, the resulting solution is called iodine aqueous solution.

When alcohol and water are mixed, the resulting solution is called an (alcohol) solution.

After mixing salt and water, the resulting solution is called Sodium Chloride.

When iodine is mixed with alcohol, the resulting solution is called (iodine wine) and grinds.

When iodine and water are mixed, the resulting solution is called iodine aqueous solution.

Alcohol and water mix because alcohol contains hydroxyl groups and has a short carbon chain.

The hydroxyl group is a strong hydrophilic group, which can form hydrogen bonds with water molecules, and has a great affinity, which is the main reason why alcohol is soluble in water. The ethyl group in alcohol is too short and has limited hydrophobic properties, so alcohols with short carbon chains can be miscible with water. As the carbon chain grows, the solubility of the alcohol gradually decreases, to a dozen carbons, and it is almost insoluble in water.