Urgent Chemistry Emperor A few junior high school experimental principles questions.

1.Avoid splashing water.

2.The water inlet of the condenser tube can make the water cool evenly at the bottom, and it can also make the water cool for more time.

If the condenser tube is above, the water will flow down immediately, and the condenser tube will not play a role here.

3.In the same way, if the water inlet is above, the water does not stay in the activated carbon for a long time, but only flows through in an instant, and does not have a purifying effect. But if it is below, the situation is different, the water flows from the bottom to the top, and the water can be in contact with the activated carbon more fully, and the purification effect is better.

1。Drainage. 2。Because that conduit is tilted, if it is above, it will cause an uneven water cooling.

3。Ditto.

1. Prevent water splashing and flying out.

2. From the lower tube in and out of the upper tube, the condensation time can be more sufficient, such as the upper and lower out, under the action of gravity, it will quickly pass through the condenser tube can not fully act.

3, in fact, is somewhat similar to the principle of 2, you think, for example, from top to bottom, water is not immediately affected by gravity to flow down, and from bottom to top, it will take longer to pass through carbon particles, so that the purification is more sufficient.

1.Prevent liquid from spilling 2The principle of counter-current, so that the water fills the condenser tube and fully condenses 3The counter-current principle slows down the speed and makes it fully purified.

1 Place the bottom of the funnel against the inner wall of the beaker to prevent the droplets from splashing and allowing the liquid to flow down the line.

2. The water inlet of the condenser tube is below, and the water outlet is at the top, so that the water is filled with the condenser tube, so that the gas can be fully condensed.

3. The water inlet of the activated carbon water purification device is also below, and the water outlet is above, so that the water can be fully filtered (the probability of impurities below is large).

It seems that the radish in Beijing's heart is an indicator, and there are hints on the topic of what color is acid and what color is alkali, otherwise I don't know;

White vinegar, a typical acidic substance, is only not as acidic as HCl and H2SO4 at the same concentration;

Toilet Cleaner, a typical acidic substance, the human intestine is an alkaline environment, so the feces are also alkaline;

Fruit juice contains a lot of weak acids and carboxylic acids, which are acidic;

The typical Ca(OH)2 of lime water is a medium-strong alkali;

Soapy water, mainly NaCO3, is a strong alkaline and weak salt solution, which is alkaline and sucrose water is neutral, so it does not change color;

Kitchen detergents are alkaline substances that are mainly used to hydrolyze oil stains – mainly higher fatty acid esters (which involve high hydrolysis reactions).

Tap water is mainly cl2 bleaching, and bleaching powder is also used, but most of them are still acidic, but it should be noted that HCro has bleaching, but the amount is very small, and it is estimated that the questioner wants you to look at it as acidic; If it is used to kill the virus with bleaching powder, it will become alkaline, and the last advantage is not accurate; However, it is common to calculate according to acidity.

Test for yourself and don't cheat!

When white acetic acid turns red, it has the same effect as purple litmus test solution, and you will know if I don't say anything else.