Chemistry issues. Trouble, chemistry problem, urgent, thanks

First Cycle: Hydrogen Helium - Invasion.

Second Cycle: Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Fluorine, Neon -- Carp Skin, Carbon Egg, Fufu Milk, Third Cycle: Sodium, Magnesium, Aluminum, Silicon, Phosphorus, Sulfur, Chlorine, Argon -- That beautiful Guilin has green teeth.

Fourth Cycle: Potassium, Calcium, Scandium, Titanium, Vanadium, Chromium, Manganese -- Married to Kangtai Counter-Revolutionary, Iron, Cobalt, Nickel, Copper, Zinc, Gallium, Germanium, Tiegu, Pain, Arsenic, Selenium, Bromine, Krypton -- Angry Shock.

Fifth cycle: rubidium, strontium, yttrium, zirconium, niobium -- so tell you molybdenum, technetium, ruthenium -- unbelievable.

Rhodium, palladium, silver, cadmium, indium, tin, antimony--Daddy, Yinge, Insiti tellurium, iodine, xenon, --Location immortal.

Sixth cycle: cesium, barium, lanthanum, hafnium, color, shell, blue, tantalum, tungsten, rhenium, osmium -- but (see) black (crow) (lead) goose iridium, platinum, gold, mercury, stone, lead, -- a white towel for it to hold bismuth, polonium, astatine, radon -- will not love winter (day).

Seventh cycle: francium, radium, actinium -- lightning protection!

1-20 elements, just read horizontally, read more and remember it.

The pronunciation of the general elements is similar to that of the non-partial half.

If you have a vertical back, you are more familiar with the elements of a family, and the chemical properties of the elements of a family are very similar, which is very helpful for doing problems. Just take a look at it and memorize it. If you are in junior high school, you can be in the top 20.

High school students are not too much, but if you are preparing for the Chemistry Olympiad, it is different, and the sub-clan also needs to be familiar.

The name of the element is usually similar to that of the side.

Invasion. Once upon a time, there was a wealthy family who used carp skin to hold charcoal and boiled eggs to feed the blessed wet nurse, and this family had a very beautiful daughter named Guilin, but she had two green front teeth (wow, that's terrifying), and later she could only marry a counter-revolutionary named Kangtai. On the day she first got married, she was pinched hard by her sister-in-law, known as "Tie Gu", and her mother was angry and went into shock at that time.

It's terrible, and my mother's family is going to sue me. Tiegu's father and her brother entered the county prince's mansion at night, stole the big seal and ran westward, to a place where immortals lived.

The scenery here is beautiful: the blue river with colorful shells, a crow with a long white scarf to lead a goose, because they don't like winter, so they want to go to the south, along the way also remind each other: the south is rainy, pay attention to lightning protection.

Have you finished reading it? Now let's condense this story and spend another 6 minutes memorizing it.

First, there is a blue precipitate, and when an appropriate amount of formaldehyde solution is added, the brick red precipitate.

Equation: CuSO4+2NaOH=Na2SO4+Cu(OH)2 HChCHO+4Cu(OH)2 Heating 2Cu2O +CO2+5H2O What is this reaction with the presence of aldehyde groups!!

Amount of %Na2S2O3 substance = mol

2 Na2S2O3 + I2 = Na2S4O6 + 2 Nai, indicating the formation of I2 with mol.

ca(clo)2 + 4 ki + 2 h2so4 = caso4 + k2so4 + 2 kcl + 2 i2 + 2 h2o

It is indicated that Ca(clo)2 with mol is involved in the reaction.

Mass = mol 143 g mol = g And because there is only g of original bleaching powder in 25 ml of Ca(ClO)2 solution, the mass fraction of Ca(ClO)2 in the bleaching powder is = %.

kclo3

Potassium chlorate KMNO4

Potassium permanganate. Multiply 180 by each percentage, that is, the mass of each element, and then divide it by its own atomic weight, which is the number of atoms.

h)180*

c)8/1=8

h)108/12=9

c) So C9H8O2

This method is relatively simple.

Potassium chlorate, potassium permanganate.

c：h：o=60/12：：

then the simplest form is.

Then the molecular formula should be C9H8O4

(1) It was concluded that fresh chicken liver slices contain catalysts that can decompose H2O2.

2) The purpose of the first step experiment was to demonstrate that Mno2 can catalyze the decomposition of H2O and that the gas is produced due to H2O. Otherwise, if there are only 2 or 3, it is not certain whether this gas is produced from the chicken liver.

Hope it helps

Select AD

a The original acetic acid is a weak electrolyte with weak electrical conductivity. Ammonia and acetic acid are added to react to form ammonium acetate salt, which is a strong electrolyte and has significantly enhanced conductivity;

b Since the original NaOH conductivity is relatively strong, the conductivity enhancement is not obvious after the addition of Cl2;

c Conductivity unchanged;

d The original H2S is a weak electrolyte with weak conductivity. The addition of Cl2 and H2S reacts to form HCl, which is a strong electrolyte with significantly enhanced conductivity.

I chose ABC because it is a strong electrolyte, so it does not change much.

D should not change (or weakly decrease) and then rise, because the word "a small amount" 2 determines that H2S will not react much, as a 2-element acid, it will pull the ionization equilibrium forward after the reaction, so that the free ions will not suddenly increase.

There is little change in DA, the ionization ability of acetic acid is already strong, and ammonia is introduced, even if ammonium acetate is generated, it is not very stable.