Several questions related to chemistry, questions about chemistry

Heating. Add hydrochloric acid.

Ditto. What is nshso3? If NaHSO3 plus NAOH plus hydrogen peroxide. and copper heating, and iron heating (sulfuric acid to be concentrated) plus NaOH plus BA(OH)2

None of them dissolve may take a few steps.

nabr

The aqueous solution is colorless.

Remember that all sodium salt solutions are colorless.

Valence electrons are the electrons that participate in chemical reactions, or simply understood as electrons related to valence.

For the main group of elements, it is the outermost electron, and for the transition element, it also includes part of the secondary outer shell and the penultimate shell.

Diagonal principle.

Generally refers to:

li-mg，be-al

The three pairs of elements in the diagonal line, b-si, have little difference in radius, and the elemental properties are very similar.

Don't expand it arbitrarily.

For example, the combustion reaction product of MG and O2 is MGO, and the ignition product of Li in the air is also Li2O, not Li2O2, and Mg(OH)2 is insoluble, and the solubility of LiOH is not large,。。 Both oxides and hydroxides of Al are amphoterics, as are those of Be.

The mass fraction of hydrogen in H2O2 is 2 34=, the mass fraction of hydrogen in water is 2 18=, and the mass fraction of hydrogen in solution is 8%, which is calculated by the deca cross method.

That is, the mass percentage of H2O2 is: 100 grams of this solution contains 100 grams of H2O2 and X grams of O2.

2h2o2=2h2o+o2

2*34...32 then there is 2*34, and the solution is x=, so the total mass of the solution is 100+, then the mass fraction of the solute is.

8, i.e. select B

In middle school, it is basically memorized, such as the three strong acids (H2SO4, HNO3, HCl), and the two strong bases (NaOH, Ca(OH)2). After learning the periodic table, you can combine analysis to help memorization, for example, the leftmost element of the element in the same period corresponds to the strongest hydrate acidity, and the rightmost element corresponds to the hydrate acid.

Option b analysis: 2H2 + O2 = H20, H: 100 8% = 8 (g), all turned into water H2O is M:

8: m = (2 1 2): 18 2, m = 72 (g), the rest of the mass is O, due to the full reaction, all released in the form of O2. The addition of 8gcuSO4 is the solute;

C=solute (solute + solvent) 100%=8 (72+8) 100%=10%, so choose B.

Set water xmol, hydrogen peroxide ymol. Then 2x+2y=8, 16x+32y=92Solution:

x=9/4mol,y=7/4mol。After the complete reaction, oxygen is produced 7 8mol*32g mol=28gSoluble mass fraction:

8g/(100-28+8)g*100%=10%

Iron reacts with more non-oxidizing acids to form 2+ iron ions, such as hydrochloric acid. So iron + hydrochloric acid will only produce ferrous chloride. Choose C.

Clothes: The colors of clothes, there are many more colors than before. Synthetic materials are more and more and better, better, breathable colors.

Food: There are more and more types of food additives, including color, aroma and taste, and various food processing products.

Lived original wooden windows, iron beds, aluminum alloy doors and windows, plastic doors and windows, paints, lime latex paint building supplies.

Due to the advancement of chemical technology.

Primary option D: A has a lot of intracellular fluid

b Acetylcholine is found inside cells.

C Answer: To achieve the pH required by the human body, it is not necessarily acidic.

Question 7: Option B Only iodine can make it discolor, but iodized salt cannot.

Other questions are either without pictures, or they may have typed the questions wrong (or I can't understand them), for example, the second question has no pictures, and the third question is sorry, I really have to write.

lh2SO4 I don't understand these you question As for the chemistry ph** I forgot a lot I just didn't read it to the best of my ability.