I am in dire need of information about World Water Day on 22 March 2008?????

(1) Activated carbon can remove the odor in the water through adsorption Therefore fill: b (2) Iron rust is a process of chemical reaction when iron coexists with oxygen and water Therefore fill in: O2 (oxygen or air); H2O (water).

Because there is a small amount of oxygen dissolved in water, the purpose of heating and boiling is to remove oxygen (air) dissolved in water

3) The mass of sodium chloride is: 50g 10% = 5g The mass of water is: 50g-5g = 45g

Therefore, fill in: 5g; 45g．

The corresponding information is: sodium chloride solution.

Quality score: 10%.

1) A. Stirring can accelerate the dissolution and make the solution more uniform, but it will not remove any substance, so A is not suitable;

b. Adsorption refers to the adsorption of gas or liquid on the surface of the solid, so this method can be used to suck out the odor in the sewage to achieve the purpose of removing the odor, so B is suitable;

c. The function of standing is mainly to make the precipitate sink to the bottom of the solution to achieve the purpose of separation, and it cannot remove the gas, so C is not suitable;

d. Filtration can remove insoluble matter and make the solution more homogeneous.

1. Stable, but can not remove gas, so D is not suitable;

So the answer is b

2) Although the iron nails in the test tube A are immersed in water, there is a layer of vegetable oil on the water, which plays the role of isolating the air, and the iron nails in the test tube A have no obvious changes, indicating that only the condition of contact with water can not make the iron rust;

c. There is air in the test tube, but the cotton and desiccant absorb the water, and there is no obvious change in the iron nails, indicating that there is no water, only oxygen, and the iron cannot be rusted;

The iron nails in the test tube are immersed in water, and there is no substance at the mouth of the test tube for air isolation, and the iron nails are obviously rusted, indicating that the iron can only rust when it is in contact with oxygen and water at the same time

So the answer is: O2

oxygen or air), h2

o (water); In the process of boiling distilled water, the air in the water escapes, so the distilled water added to a should be boiled in advance, the purpose of which is to drive away the oxygen (air) dissolved in the water;

3) From the title, it can be seen that 50g of sodium chloride solution with a mass fraction of 10% is based on the mass fraction of sodium chloride = the mass of sodium chloride.

Solution quality. 100%, the mass of sodium chloride can be calculated as: 50g 10% = 5g; Then the mass of water = solution mass - solute mass = 50g - 5g = 45g;

The information on the label should include the name and concentration of the solution, so the information on the label is: 10% NaCl

(1) The boiling method is commonly used in life to reduce the hardness of water;

2) The atom gains and loses electrons to form ions, and magnesium ions are formed by magnesium atoms losing 2 electrons, so the number of electrons outside the nucleus of magnesium ions is 12-2=10;

3) Water is generated when organic matter is burned, for example: CH4+2O2 ignition

co2+2h2o；

4) The main principle of water fire extinguishing is to reduce the temperature of combustibles to below the ignition point;

5) In the laboratory, calcium oxide is often used as a desiccant because calcium oxide can react with water to form calcium hydroxide, and the chemical equation is: CaO+H2O Ca(OH)2

So the answer is: (1) boiling;

3）ch4+2o2

Igniteco2+2h2o；

4) Lower the temperature;

5）cao+h2o═ca（oh）2．

(1) Activated carbon has an adsorption effect, which can adsorb pigments and odors in water, and can be achieved by using the adsorption effect of activated carbon; There is no new substance formed in the adsorption process, which is a physical change; Alum can adsorb suspended solids in water and is a commonly used flocculant

2) Fish can breathe in water because of the dissolved oxygen in the water, and the chemical formula of oxygen is: O2;

According to the representation method of the ion: in the upper right corner of the element symbol representing the ion, mark the number of positive and negative charges carried by the ion, the number is in front, the positive and negative signs are in the back, and when there is 1 charge, 1 should be omitted; Calcium and magnesium symbols: Ca2+, Mg2+; Boiling or distillation is often used to reduce the hardness of the water

So the answer is: (1) physical change; Alum; （2）①o2；②ca2+；mg2+；Bring to a boil

1) A Water is one of the most common solvents, and most of the water in nature contains impurities, so a is correct;

b Ca2+ in water

The increase of Mg2+ will cause a large difference in the hardness of the water body, rather than eutrophication pollution, so b is wrong;

c The hardness of the water cannot be reduced by filtration or distillation, so c is wrong;

d The chemical reaction occurs in the aqueous solution, and the reaction speed is relatively fast and sufficient, so d is correct;

2) The effect of adding alum to the river water is to adsorb impurities and make them settle; Activated carbon has adsorption properties, which can adsorb the color and odor of the pure pigment in the water sample, which is a physical change; The algebraic sum of the valencies of the elements in the compound is 0, so sodium ferrite (Na2

FeO4 can be used for drinking water disinfection, where the valency of iron is +6;pH test paper can be used to determine the pH of groundwater; Dry ice is easy to sublimate, sublimation and heat absorption, used for artificial rainfall, and dry ice is solid in physical properties;

3) The deflated table tennis ball in life can bulge up when put into hot water, because the intermolecular interval increases with the increase of temperature; Water is the source of life, but it does not provide energy, such as steamed buns; Water has a wide range of uses, such as water is used to prepare solutions

So the answer is: (1) BC; (2) adsorb impurities and make them settle; Activated carbon; Physics; +6 valence; pH test strips; Solid; (3) Water is used to prepare solutions

A waste battery, mainly to prevent the pollution of heavy metal ions such as Pb2+, HG2+ and other heavy metal ions in the battery, so A is wrong;

b Phosphorus-containing substances can lead to eutrophication of water, and the use should be reduced, so b is correct;

c Industrial sewage contains a large number of harmful substances, which must be treated before discharge, so C is correct;

d The method of sprinkler irrigation and drip irrigation can save water resources to the greatest extent and effectively avoid waste, so D is correct

So choose A