Some chemistry questions are answered by well wishers

1. Judging that the valency of R is -2 from H2R, then the highest positive valence of R is +6, then the chemical formula of the oxide is Ro3, and the relative atomic mass of R is 32 according to the oxygen in Ro3 accounting for 60%.

2. The four elements of ABCD are AL Cl O Na, and the number of protons is represented by the schematic diagram of the atomic structure.

3. The elements Y and Y are Cl Mg, both of which are in the third period, with Mg in the 2nd main group and Cl in the 7th main group.

Two hydrogen atoms and one sulfur atom in H2S form two common electron pairs, the MGO magnesium atom loses two outermost electrons and becomes a magnesium ion, and the oxygen atom gains two electrons and becomes an oxygen ion.

1, The element is sulfur, answer 32

2, A is aluminum, B is chlorine, C is oxygen, and D is sodium.

3, x is chlorine, the third period, the seventh main group, y is magnesium, the third period, the second main group.

Hydrogen sulfide H2S, magnesium oxide mgo, as for their electronic representation, because there is no such symbol, it is impossible to write the combination of non-metallic elements, it is a shared electron pair, the combination of metal and non-metal, is a combination of ionic bonds, and it should be in parentheses.

Knowledge points involved: The content of elements in the earth's crust is from high to low: oxy-silicon-aluminum, calcium, sodium, potassium and magnesium.

Understanding of the main group elements and the structure of the electron layer.

Mastery of the various properties of inorganic elements.

cl2+h2=2hcl

naoh+hcl=naoh+h2o

2NaOH+Cl2=Naclo+H2O+NaClNaOH is.

The total mass of the solution is 100*

The mass fraction of the original NaOH solution was:

2) Na+ is total, NaCl

And. NACLO.

cl- for. 3) It is known by the reaction equation.

Reactive with Cl2:

NaOH and Cl2.

It also reacts with HCl.

HCL is. H2 is Cl2.

The total cl2 is.

The ratio is 2:3

(2) According to the reaction CL

h＝2hcl，cl

2naoh=nacl+

naclo+h

o，hcl+naoh＝nacl+h

o Knowable. Solution. Middle. ：n(na

n(cl+n(clo

l×=n(cl

mol。(3) Under the same conditions, the volume ratio is equal to that of the substance.

Measure. to solve. First according to.

Naclo.

Measure. OK with h

Reaction after overdose. Chlorine. Target.

amount, then according to the NACL with.

Naclo's poor. Measure. Are you sure.

Hydrogen. Target. Measure.

N (excess Cl after reaction with H.)

n(naclo

mol, then n(h

N (Cl reacting with H.)

mol: v(cl

v(h＝（mol=3︰2

There is a problem with the data, and na is a total of talents.

Naclo has a lot of it.

Filtration refers to the filtration of liquids from insoluble solids.

aAll are liquids. Don't pretend to be a leak.

b are all soluble in water wheel sensitive. No.

cYes, it is possible to separate sediment and water.

Is it OK to fill in D?

That is. Calcium carbonate and water bar.

A with a separating solution B with a hall rotten crystals.

Of the following mixtures, the keys are made using the method of over-muffling filtration to separate them

a.water and vegetable oils.

b.Table salt and sucrose.

c.Mud water.

d.Barium sulfate and water

Answer CD

Answers b, c, a, d

Analysis: There are 3 stable isomers of the molecular formula C3H6O: acetone, propionaldehyde, and propenol A can react with Schiff's reagent, indicating that A is propionaldehyde (Schiff's reagent can be used to identify aldehydes and ketones. After the action of aldehydes and Schiff's reagent, the solution is purplish-red, and usually, ketones do not react with Schiff's reagent).

Based on the conditions, B is inferred to be acetone.

A hydrogenation to produce C is 1-propanol (primary alcohol); b hydrogenation to produce d as 2-propanol (belonging to the secondary alcohol position, which is called primary, middle, uncle, and quarter.

a c

1. The total energy of the organism is higher than the total energy of the reactants, that is, the reaction is an endothermic reaction, only A is endothermic, and the others are exothermic reactions.

2. There is no need to heat when the exothermic reaction occurs, many exothermic reactions need to be reacted at high temperatures, such as nitrogen and hydrogen to synthesize ammonia, exothermic but need to initiate the reaction at high temperature, and then exothermic will be released to maintain the reaction temperature.

required for endothermic reactions.

Not necessarily. Heating can only take place: for example, the reaction of calcium hydroxide and ammonium chloride can take place with stirring.

Select A. for this questionThe so-called chiral carbon atom refers to the four groups attached to a carbon atom that are different.

If this carbon atom forms a double or triple bond, it can never be a chiral carbon atom.

And the carbon atom in methyl (-ch3), methylene (-ch2-) cannot be chiral carbon.

Because they both have more than two hydrogen atoms attached, the dimethyl group (CH) in the diagram appears to be a chiral carbon.

But if you look closely, it connects two identical groups, the two groups on the right and on the top.

Thus, there are no chiral carbon atoms in this compound. A's narrative is incorrect.

b.NMR hydrogen spectroscopy is a way to check the number of equivalent hydrogen classes, and there are as many peaks as there are equivalent hydrogen classes.

The two hydrogens on the heterocyclic are not equivalent, this is two, plus the amino group one is three, and there are a total of five classes of equivalent hydrogen on the side chain (note that two groups attached to the hypomethyl group are equivalent) so there are a total of eight classes of equivalent hydrogen, so there are eight peaks. B's narrative is correct.

c。This heterocyclic is aromatic, so the atoms on the ring must be in a plane, or you can understand that every ring-forming atom is sp2 hybridized, therefore, the four nitrogen on the exchange must be coplanar, and the atoms directly connected to the ring when the amino nitrogen atom is also coplanar with the ring. C's narrative is incorrect.

d。The compound has an amino group, which is alkaline and can react with hydrochloric acid. There are also ester groups on the side chains, which can be hydrolyzed with sodium hydroxide. D's narrative is correct.

dt You have studied calculus, dt even if the temperature changes, specific to this problem dt=(

Bring in dt=kbmb and you get mb=

Colloids are dispersed systems with particle diameters ranging from 1 to 100 nanometers, which can be divided into gas-liquid-solid states, colloidal, and nano-scale, which is also in the range greater than 1 nanometer.

When a beam of light passes through the colloid, a bright "pathway" can be observed in the colloid from the vertical direction of the incident light, which is called the Tyndall phenomenon, also known as the Tyndall effect (the title has already given the solution).

a d

Learn what nanomaterials are.

Too much, hehe, help you answer a few words with less writing (2)b (3)d (4) the first question choose h2co3 the second question hcl the third question cu(oh)2 the fourth question hcl gas (5) I can't finish this I can't draw the line (6).