Which of the following statements is correct? Which of the following statements is correct?

a.The information on the Internet is both true and wrong, so it is incorrect;

b.Although there is a lot of information on the Internet, there is also a lot of information that is not available, such as the latest high-tech information and so on;

c.You must be clear about this when you use the computer, if there is a virus intrusion, it must be damaged;

So, d is correct that collecting and organizing information in this way will help us use the information better.

Answer: The compound that is all formed by covalent bonds in C is a covalent compound, and the compound that contains ionic bonds is an ionic compound, so both AD are incorrect, and C is correct. There is no chemical bond present in the noble gas molecule, b is incorrect. The answer is C.

Choose. AA, electricity is generated by hydropower, wind energy, coal, nuclear energy, etc., and belongs to the secondary energy source.

b, hydropower, is natural, is a first-class energy source.

c, coke oven gas, which is formed when coal is burned, belongs to the secondary energy source.

d, natural gas is naturally occurring and belongs to the primary energy source.

Answer: Item ab describes the Loess Plateau, the Qinling Mountains are the watershed of the Yangtze River and the Yellow River, and the boundary mountain between Jiangxi and Fujian is the Wuyi Mountains.

a. None of them respond.

B, Fe and water do not react to form alkali, to form ferric tetroxide.

c. Yes, the generation of Li2O, CO2, P2O5D, and Na2CO3 is very stable, and generally does not decompose when heated.

A is adjacent to -OH and C with H, then the elimination reaction can occur, so A is correct;

b contains phenol-OH, substitution reaction with modified bromine water, C=C, addition reaction with bromine water, then 1mol of the substance can consume 4 molbr2

Therefore b is correct; c contains -OH, -COOH and phenol-OH, and all react with Na, so 1mol of the substance can consume 6mol of Na by reacting with sufficient amount of sodium metal, so C is correct;

d Phenol-OH, -COOH, -Cooc- react with NaOH solution, then 1mol of the substance can consume 4mol of NaOH in the empty reaction with a sufficient amount of NaOH solution, so D is wrong;

Therefore, choose D

Answer: Aluminum is the most abundant metal element in the earth's crust, but the use of aluminum by human beings lags behind the utilization of copper and iron, so item A is wrong; At present, there are only more than 90 kinds of pure metals made, but the alloys made by some pure metals according to a certain composition and quality ratio have reached thousands of Qi Liang, and the alloy performance is better than that of pure metals, which is more suitable for different needs, so most of the metal materials used in daily life are alloys, so item B is wrong, and item C is correct; Other metals or non-metals are fused in the alloy, and most of their properties are different from those of the original metal, so D is wrong

This question tests the students' understanding of the concept of alloys The properties of alloys made by fusing some metals or non-metals together with metals will change, and the strength and hardness of the coarse bridges of alloys are generally higher than those of the pure metals that compose them, and the corrosion resistance is also better, so alloys have a wider range of uses

Yes, the answer is A

a. In water vapor, water exists in the form of a single water molecule, and in liquid water, usually several water molecules are combined by hydrogen bonding to form (H2O)N; In solid water (ice), water molecules bond to each other in a large area of geocentric hydrogen"Associates", become a loose crystal, because there are many voids in the structure of the ice, causing the volume to expand and the density to decrease, so the ice will float on the surface of the water, so a is correct;

The existence of hydrogen bonds increases the melting point and boiling point of substances, which is due to the existence of hydrogen bonds, which makes the molecules produce a strong binding force, and to vaporize liquids and liquefies solids, additional energy must be added to break the hydrogen bonds between molecules, so the existence of hydrogen bonds leads to an increase in the heat of vaporization and sublimation of some substances, so B is wrong;

c hydrogen bond is a kind of intermolecular force, the intermolecular force only exists in the solid liquid state, and the gaseous state of the intermolecular force is almost 0, so c is wrong;

d hydrogen bonds can be broken at any time and generated at any time, for example, water becomes water vapor hydrogen bond breakage, water vapor becomes water hydrogen bond production, so d is wrong;

b. Due to the existence of hydrogen bonds, the heat of vaporization of some substances increases, and the heat of sublimation increases, c. Hydrogen bonds can only exist in liquid or semi-solid states, and d. Hydrogen bonds are not stable chemical bonds, but molecular forces.

dCorrect a** element compounds must be oxidizing not necessarily strong oxidizing b For example, tetravalent sulfur (cation) can also become hexavalent sulfur can be reduced c, the strength of reduction is not determined by the number of electrons lost, it is determined by the difficulty of electron loss, d, such as: concentrated H2SO4 does not react with SO2.

or 2 kinds of solid strong oxidants and strong reducing agents, which may not react.

a.False, hormones are not necessarily proteins, so the constituent units are not necessarily all amino acids BFalse, the products that are broken down by lysosomes remain in the cell or excreted outside the cell, depending on whether the broken down products are useful or useless Normally, some of the protein products broken down by lysosomes are essential amino acids that cannot be synthesized by the body, and these are reused.

c.That's right. d.Wrong, there are also in yeast.

Combustion in oxygen is an oxidation reaction, but not a chemical reaction.

2.The chemical reaction must be to produce a substance.

3.The reaction that occurs between a substance and oxygen is an oxidation reaction and not necessarily an oxygen.

The following statement is correct: 4 magnesium strips are burned in the air, which is both a chemical reaction and an oxidation reaction.

1. The oxidation reaction must be a chemical reaction.

Counter-example: Methane and oxygen reactions.

2 Any reaction that occurs between two or more substances is a chemical reaction counterexample: methane and oxygen reaction.

3. The reaction of a substance with oxygen is only an oxidation reaction.

Counter-example: sodium and water react.

1. The oxidation reaction must be a chemical reaction.

Wrong. For example, the combustion of methane produces CO2 and water.

2. Any reaction between two or more substances is a chemical reaction error. The product must be a substance.

3. The reaction of a substance with oxygen is only an oxidation reaction.

Wrong. As long as there is electron gain and loss, the reaction is a redox reaction.

4. The combustion of magnesium strips in the air belongs to the chemical reaction and the oxidation reaction pair. There is only one product, and there is electronic gain and loss.

4 is right.

1.False: For example, the displacement reaction CuCl2 + Zn = Cu + ZnCl2 is an oxidation reaction but not a chemical reaction.

2.False: For example, NaOH + HCl = NaCl + H2O is not a chemical reaction.

3.False If there is a change in valency, it belongs to the oxidation reaction, for example, H2+Cl2=2HCl does not have oxygen, but it belongs to the oxidation reaction.

4.Correct 2mg+O2=ignition=2mgo belongs to the chemical reaction and also belongs to the oxidation reaction.