Thank you for your kindness!! High School Chemistry, thank you!!

The inside of the battery is from the negative electrode to the positive electrode.

Honestly, I don't get what you mean.

During electrolysis, electrons flow into the cathode, and cations are adsorbed on the surface of the cathode (opposites attract) and reduced, so cations flow from the anode to the cathode in the solution, while anions are the opposite, and the current flows from the anode to the cathode.

From the external power supply, the current flows from the positive electrode, and flows in from the negative electrode of the battery after passing through the sodium chloride solution, and the direction of movement of the electrons is opposite to the direction of the current, so what you said is correct in the front, and in the end it is equivalent to the electrons flowing out of the negative electrode instead of the current flowing out. The battery is positive to negative on the outside and negative to positive on the inside.

This difference between chemistry and physics! It is the negative electrode that chemistry loses electrons! And physics is electron, and what comes out is the negative electrode! So no contradiction! Take a good look at what your chemistry book says about electrodes! Let's make a difference between the physical and chemical electrodes!

Options. Hydrochloric acid reacts with sodium carbonate and sodium bicarbonate, so it cannot be selected.

Option b. 2NaHCO3 is heated to generate Na2CO3+CO2+H2O while sodium carbonate does not react. Therefore, choose B

c option. NAOH reacts with NAHCO3. However, the addition of NaOH introduces new impurities. Hence the error.

d option. Na2CO3 + CO2 + H2O to produce 2NaHCO3 which is the removal of Na2CO3. Therefore, it cannot be chosen.

Broad definition of combustion: combustion refers to any violent reaction of luminescence and heat, which does not necessarily require oxygen to participate, such as the reaction of sodium metal (Na) and chlorine (Cl2) to form sodium chloride (NaCl), which does not involve oxygen, but is a violent chemical reaction that emits heat and heat, and also belongs to the category of combustion. It doesn't have to be a chemical reaction, such as the combustion of nuclear fuel.

It contains Na+, which will interfere with the flame color reaction, and sulfuric acid in C does not volatile.

And d hydrochloric acid is volatile.

Heating NaHCO3 pyrolysis.

Combustion must have oxygen involved, because mg can be burned in CO2, H2 can be burned in Cl2, etc.

3 d.Dilute hydrochloric acid removes the platinum wire that has been oxidized, will not interfere with the flame color reaction, Na+ will cause interference, and sulfuric acid is easy to oxidize platinum.

1 Option B removes NaHCO3 and generates NA2CO3 at the same time

2 Choose d to give a counterexample, e.g. mg burns in n2.

3 Select DA and B contain Na+, which will interfere with the flame color reaction, C sulfuric acid is not volatile, high boiling point, and its salt is not easy to volatilize at high temperature, and it is impossible to wash the substances adhered to the platinum wire during washing. The hydrochloric acid is volatile, and its salt is also volatile at high temperature, and when burning, hydrochloric acid and its salts can be volatilized together to achieve the purpose of washing.

1a2d3d

After sodium bicarbonate is heated, it is decomposed into sodium carbonate, carbon dioxide, and water does not produce new impurities, and magnesium and carbon dioxide are also combustion reactions, but there is no oxygen to participate.

On the one hand, acid is used to remove metal oxides from the surface of the platinum wire.

On the other hand, hydrochloric acid is a volatile acid, and its salts are also easily volatilized and removed when burned.

In short, the impurities on the platinum wire can be well removed, which is convenient for completing the experiment.

The amount of chloride ion is moles, and it can be inferred that magnesium chloride is mol, so magnesium chloride is moles per liter.

Potassium dichromate K2Cr2O7 solution orange.

Potassium chromate K2CRO4 solution yellow.

Formaldehyde is a gas at room temperature.

Chloromethane is a gas at room temperature.

Cu(OH)2 blue flocculent solid.

Linite stands for nano2 oxidizing reducing alkaline soluble toxic Na2SO3 and acid reaction reducible reduction to Na2SO4 peroxide represents Na2O2 oxidizing reducing O2 in contact with CO2, H2O2

H2O2 Common Oxidant Reducible Easy to decompose when heated.

Which high school are you, English question stem???

Reason for choosing D: The algebraic sum of the elements with the highest ** is +6 valence and the lowest is -2 valence is 4, then this element is in the A group. So, a:

r is not necessarily a fourth period element, b:r is a group a element, c: a group elements have gaseous hydrides that are not as stable as gaseous hydrides of group a elements, d:

R is combined with H, R shows negative valence, R is -2 valence, therefore, the chemical formula of R gaseous hydride is H2R

As can be seen from the title, the highest positive price of r is the positive hexavalent, and the lowest negative price is the negative hexavalent. So it comes to D correct.

d, because the algebraic sum of the highest positive valence and the lowest negative valence of the main group element is 4, then the positive valence is 6 and the negative valence is -2, then it can be known that it is the sixth main group element, which can be the sulfur of the third cycle or the sulfur of the later cycle, so a, b is wrong, oxygen is the second cycle, and its stability is definitely greater than the gaseous hydride of the same periodic elements of the later period, so c is wrong, choose d

d, the key is that the algebraic sum is 4, and the so-called algebraic sum is the sum calculated with plus and minus signs.

Let the highest positive price be x and the lowest negative price be -y, then.

x+(-y)=4

x+y=8, then x=6

So for the first VIA family.

The answer is d

Two or three is more than one in this short draft 6, four or five is 10 more than three, and six or seven is 14 more than five, which is roughly a series of equal defeats.

According to the difference series, the eighth category Mori is 18 more than the seventh category