Chemistry Practice and Application 1 explains the following phenomena 1 and 2 .

1}Because the main component of the eggshell is calcium carbonate, calcium carbonate reacts with dilute hydrochloric acid to generate a large amount of gas, which adheres to the surface of the eggshell, so that the buoyancy of the eggshell increases, and the egg floats, when the egg rises to the liquid level, the bubble bursts, the buoyancy of the egg decreases, and the egg sinks under the influence of gravity. And so on and so forth, forming the above phenomenon.

2} Soda [sodium bicarbonate] powder melted water mixed into the noodles, after heat decomposed into sodium carbonate, carbon dioxide and water, carbon dioxide and water vapor overflow, can cause food to be more fluffy, sodium carbonate remains in the food.

1. The eggshell is put into dilute hydrochloric acid to react to generate a large number of small bubbles of carbon dioxide, which are distributed around the eggshell, at this time buoyancy is generated, when the buoyancy is greater than gravity, it will float, when it reaches a certain position is the bubble overflow, the buoyancy is less than the gravity, and it sinks, and the cycle repeats.

2. In the process of making pastries, sodium bicarbonate mainly reacts with organic acids to produce a large number of bubbles, so that these pastries will have many small holes.

3. Element: Fe oxide: Cuo acid: HCl base: NaOH salt: NaCl4, C

1) CaCO3+2HCl===CaCl2+CO2+H2O Because the bubbles are light, it pushes the eggshell first. When the liquid level is reached, the bubbles escape from the liquid and rise into the air, and the eggshell loses the support of the bubbles and sinks.

2) HCO3 2- +H+ ===H2O +CO2 sodium bicarbonate plays the role of foaming agent.

That's the acid-base neutralization decomposition reaction where sodium bicarbonate decomposes to produce carbon dioxide before it expands.

1. The main factors affecting the rust of iron products are moisture and oxygen, the climate in the desert area is dry, the relative humidity of the air is very low, iron and water and oxygen will undergo electrochemical corrosion, rust is fast, but the desert has less moisture, and the climate is dry all year round, so iron products are not easy to rust, and the corrosion is slow.

b. Because the rust of the outer layer of iron is rusted, the rust covers the surface, so that the iron inside is not easy to be oxidized. The water in the seabed contains very little oxygen, so iron is not easily oxidized.

a) Iron and copper have good electrical conductivity. Since iron is more active than copper, iron loses electrons as the negative electrode, and copper gains electrons as the anode, thus forming a galvanic cell and accelerating the corrosion of iron.

b) Seawater, because it contains a lot of electrolytes, is more prone to galvanic corrosion.

c) In tidal air, copper absorbs water, oxygen and carbon dioxide from the air and becomes a patina.

It should be the wrong question, it should be a triangle.

This new substance has the chemical formula CN12 or C(N3)4 or tetraazidemethane, and the cation is triazidemethane cation.

If CH3+ is a planar triangle, then this cation is also a planar triangle Look at b first, the anion and CO2 are isoelectrons, which is easily associated with azide N3-, that is, b is sodium azide.

It is known that A is composed of carbon and nitrogen, and the reaction is a metathesis reaction, so the cation of A is also composed of carbon and nitrogen. According to the analysis of the element content, the experimental formula CN9 of the A cation was obtained. Assuming CN9+, then the nitrogen element must exist as an azide root, that is, the cation of a is a triazidemethane cation, and the carbon is a sp2 hybrid, so it is a planar triangle.

44. Acid rain refers to rain with a pH less than (.

People often use air quality (air quality**, forecast) to express the quality of the air, which is based on the amount of sulfur dioxide in the air (carbon monoxide).

45. (1) 2NaHCO3 = = Na2CO3 + H2O + CO2 (2) (C6H10O5) N + NH2O NC6H12O646, (1) Grease Inorganic salts.

2) A, C (vitamin A deficiency can cause night blindness, vitamin C deficiency can cause scurvy).

3) Reductiveness. b

It's all in these books, and you can complete it with your own understanding.

This should be the indicator of air quality, right?

Select D for this question

Analysis] A The concentration of concentrated sulfuric acid decreases because concentrated sulfuric acid is absorbent, which absorbs moisture in the air. Reduces the concentration.

The concentration of concentrated hydrochloric acid decreases because concentrated hydrochloric acid is volatile, and when exposed to air, HCl volatilizes, so the concentration decreases.

Concentrated sulfuric acid is a decrease in concentration due to an increase in solvent, and concentrated hydrochloric acid is a decrease in concentration due to a decrease in solute, and the situation is different.

B Cl2 water fades red ink because HCro in chlorine water is bleaching, and its bleaching is an irreversible chemical reaction.

Activated carbon fades the ink because of its adsorption. is reversible. It's a physical change.

c Long-term exposure to bleaching powder is the decomposition of HCO after the reaction of CL- and CO2 in bleaching powder to form HCO.

Water glass, on the other hand, reacts with SiO32- and CO2 in the air to form H2SiO3, which is different.

dIn this case, it is the addition reaction of acetylene and ethylene that consumes the br2 in carbon tetrachloride!

I didn't choose DA correctly. Concentrated sulfuric acid is absorbent, concentrated hydrochloric acid is volatile, the former has an increase in solvent, and the latter has a decrease in solutes, both of which lead to a decrease in concentration.

b Not true. Chlorine water fades red ink because of its strong oxidizing properties, while activated carbon fades because it can adsorb small pigment particles.

C is not true. The reaction equation of the two is Ca(clo)2+CO2+H2O====CaCO3 (precipitation) + 2HCl, 2HClL=== Light =====2HCl+O2, which requires two steps, Na2SiO3+CO2+H2O====Na2CO3+H2SiO3 (precipitation), only one step.

d right. all react with bromine.

Glad to help you o(o

a concentrated sulfuric acid absorbs water and concentrated hydrochloric acid volatilizes.

b Chlorine water has strong oxidizing property (bleaching) of hypochlorous acid, activated carbon adsorption c bleaching powder deteriorates into calcium carbonate, and water glass deteriorates into silicic acid (but the principle of their deterioration is with water and carbon dioxide in the air).

d Discoloration is due to the addition reaction that occurs when the CD is selected

A concentrated sulfuric acid is because of water absorption, concentrated hydrochloric acid is because of volatilization b chlorine water is due to strong oxidation activated carbon is because of adsorption of pigments in water is different c bleaching powder is oxidative deterioration water glass is deterioration due to absorption of carbon dioxide in the air not redox reaction d d both are due to the opening of unsaturated bonds in the molecule and chlorine binding The principle is the same.

Originally, 30 grams, after the reaction, A is gone, C is 18 grams, D is 4 grams, a total of 22 grams, the mass is conserved, then B is 8 grams.

b React 2 grams.

Then a:b=10:2=5:1

a + b = c + d

10g (4g+8g-10g) 4g 8g

The mass ratio of A and B in the reaction is 10g:2g=5:1

a + b = c + d10g 8g 4gb=8g+4g-10g=2g

a:b=10g:2g=5:1

These questions are based on the law of conservation of mass.

Untie; a. Due to the gap between molecules, when the liquid and the liquid are mixed with each other, their volumes cannot be added, that is, the volume of the liquid after mixing is not equal to the sum of the volumes of the two liquids; So 10 ml of 10% dilute H2

SO4 with 10 ml of 90% concentrated H2

The volume of SO4 mixed with this rock is less than 20ml, so A conforms to the phenomenon of "1+1≠2";

B. Because the two do not react when mixed, there is an additive effect on the number of smart pants after mixing, so B does not meet the phenomenon of "1+1≠2";

c. The mass of the substance is unchanged, and the total mass of the total substance obtained after mixing the two substances is conserved, so the mass of the two is 2g after mixing, so C does not conform to the phenomenon of "1+1≠2";

d. According to the law of conservation of mass, the total mass of matter before and after the reaction remains unchanged, so D does not conform to the phenomenon of "1+1≠2".

So choose A

Choose not an acidic oxide.

The reaction with NH4Cl does not belong to the redox reaction.

5 Ionization must not be electrified, and galvanic corrosion may not be electrified.

7 Chlorine is not a non-electrolyte, an electrolyte is a chemical compound.

8.The compounds formed by metallic and non-metallic elements are not necessarily ionic compounds.

The choice of B NO2 is not an acidic oxide, it reacts with the base to undergo a redox reaction Correct Correct The reaction between Ba(OH)2·8H2O and NH4Cl is a metathesis reaction, and the change in valency does not belong to the redox reaction.

Electrolysis, electrophoresis, and electroplating need to be energized, and ionization can be dissolved in water or molten state, and the essence of galvanic corrosion is that the galvanic battery does not need to be energized.

Chlorine is elemental, neither an electrolyte nor a non-electrolyte, because both electrolytes and non-electrolytes must be chemical compounds.

There are exceptions, such as aluminium chloride is a covalent whole.

Solution: In the process of experiment, if the mass of the crucible is m, the measured "mass of the crucible and copper sulfate crystal (CuSO4·XH2O)" is m1, and the measured "mass of the crucible and anhydrous copper sulfate" after heating is m2, then x is calculated.