None of the above methods are very good.
Making hydrogen from sulfuric acid and active metals is expensive. And it is not suitable for making hydrogen in large quantities at home.
Electrolysis is even more costly, and while water arguably costs nothing, it uses a lot of power and is not practical. Electrolysis is indeed used in the chlor-alkali industry. But his products are fully utilized, and the overall efficiency is still considerable. And you are only required to hydrogen, the other products, so to speak, are waste, useless to you.
The hydrogen balloon vendors on the market, the hydrogen production method is very cheap and simple. It is to make hydrogen by reacting caustic soda with aluminum. Industrial caustic soda is cheap, and so is aluminum.
All you have to do is mix aluminum and caustic soda in a reaction container, add a cup of water and you have hydrogen.
Theoretically, one kilogram of caustic soda can react with 675 grams of aluminum to give 840 liters of hydrogen under standard conditions, or 75 grams of hydrogen.
This method is supposed to be the simplest and cheaper way to make hydrogen. I hope you can adopt it.
(Note: Hydrogen is flammable and explosive, have to pay attention to the safety)
2. The following is a completely correct group of summarization of knowledge on the subject () A. General knowledge of safety: add
A. Gasoline molecules in the air near the gas station, if there is a smoke and fire will lead to an explosion; alcohol lamps with alcohol vapors, blowing out with the mouth, the fire will be blown into the lamp, resulting in a light inside the lamp. Alcohol and air gas mixture explosion, so A is wrong; B, liquid hydrogen combustion puts out more heat, is the same volume of gas in the most hydrogen gas, often used for rocket launch fuel; liquid nitrogen vaporization absorbs a large amount of heat, so that the surrounding temperature is reduced, often used in refrigerants, can be used as a refrigerant in medical surgery, so B is correct; C, copper is a metal crystal, which is composed of metal cations and free electrons; oxygen The crystals belong to molecular crystals, is composed of molecules, so C is wrong; D, the human body lack of iodine will lead to thyroid disease, lack of calcium will lead to osteoporosis, lack of iron will lead to anemia, so D is wrong; Therefore, choose B..
3. How to use hydrogen safety
Must be used on site (indoor) cylinders, the number of which shall not exceed 5 bottles, and should meet the following requirements:
The room must be well ventilated to ensure that the maximum content of hydrogen in the air is not more than 1% (by volume) of the same below. The top of the building or the upper part of the external wall is equipped with air windows (building) or exhaust holes. Ventilation holes should be directed to the safety zone, the number of indoor ventilation shall not be less than three times per hour, accident ventilation shall not be less than seven times per hour.
The distance between the hydrogen cylinder and containers and cylinders holding flammable, explosive, combustible substances and oxidizing gases should not be less than 8 meters.
The distance from open flames or ordinary electrical equipment should not be less than 10 meters.
The distance to air-conditioning units, air compressors and ventilation equipment, such as suction vents should not be less than 20 meters.
The distance to other combustible gas storage locations should not be less than 20 meters.
There is a fixed gas cylinder bracket.
Cylinders used in multi-storey buildings, in addition to the special needs of production, it is generally appropriate to be arranged on the top floor against the outside wall.
The use of gas cylinders, prohibit knocking, collision; shall not be close to the heat source; summer should be prevented from exposure to the sun.
Specialized pressure reducer must be used, and when opening, the operator should stand behind the side of the valve opening, and the action should be gentle.
Valve or pressure reducer leakage, not to continue to use; valve damage, it is strictly prohibited in the bottle under pressure to replace the valve.
The gas in the bottle is strictly prohibited from exhaustion, should retain 0.5 kg force / cm - 2 kg force / cm above the residual pressure.
4. A little knowledge about fire
Fire is a disaster caused by uncontrolled combustion in time and space. Among the various disasters, fire is the most frequent and most common threat to public safety and social development of one of the main disasters. Humans are able to use and control fire is an important symbol of the progress of civilization. So that the history of human use of fire and the history of the fight against fire is accompanied by each other, people in the use of fire at the same time, and constantly summarize the laws of fire, as far as possible to reduce the fire and the harm it causes to human beings. In the long history of human development, fire, burned out the history of blood; fire, ignited the splendor of modern society. As the legend says, fire is a "god" with a dual character. Fire brings civilization progress, light and warmth to mankind. However, sometimes it is the friend of mankind, sometimes it is the enemy of mankind. Uncontrolled fire can cause disaster to mankind. For fire, in ancient China, people have summarized the "prevention as the first, save the second, quit as the next" of the old city fire scene inspection. With the continuous development of society, in the social wealth is increasing at the same time, leading to the occurrence of fire danger is also increasing, the danger of fire is also getting bigger and bigger. According to statistics, the average annual loss from fire in China was less than 250 million yuan in the 1970s and less than 320 million yuan in the 1980s. In the 1990s, especially since 1993, the direct property loss caused by fire has increased to more than one billion yuan per year, with an average annual death rate of more than 2,000 people. Practice has proved that with social and economic development, the importance of fire prevention work becomes more and more prominent. "Prevent fire and reduce the risk of fire" is the overall summary of the significance of fire legislation, including two meanings: First, do a good job of preventing fires to prevent the occurrence of fire; Secondly, the fire is absolutely not possible, and once a fire occurs, it should be timely and effective in fighting to reduce the risk of fire. Fire Classification" (GB/T 4968-2008 November 4, 2008 release May 1, 2009 implementation) fire according to the type of combustible material and combustion characteristics, divided into A, B, C, D, E, F, six categories. A class of fires: refers to solid material fires. This material usually has the nature of organic matter, generally in the burning can produce burning embers. Such as wood, coal, cotton, wool, hemp, paper and other fires.Class B fires: refers to liquid or meltable solid material fires. Such as kerosene, diesel fuel, crude oil, methanol, ethanol, asphalt, paraffin and other fires.Class C fire: refers to gas fires. Such as gas, natural gas, methane, ethane, propane, hydrogen and other fires.Class D fire: refers to metal fires. Such as potassium, sodium, magnesium, aluminum-magnesium alloy and other fires.Class E fires: electrically charged fires. Objects electrically charged combustion fires.Class F fires: cooking appliances within the cooking material (such as animal and vegetable fats and oils) fires. Fighting measures to fight class A fires can choose water-type fire extinguishers, foam fire extinguishers, ammonium phosphate dry powder fire extinguishers, halothane fire extinguishers. Fighting class B fires can choose foam fire extinguishers (chemical foam fire extinguishers are limited to extinguish non-polar solvents), dry powder fire extinguishers, halothane fire extinguishers, carbon dioxide fire extinguishers. Fighting class C fires can choose dry powder fire extinguishers, halothane fire extinguishers, carbon dioxide fire extinguishers. Fighting class D fires can choose powdered graphite fire extinguishers, special dry powder fire extinguishers, can also be used instead of dry sand or cast iron chips. Fighting electrified fires can choose dry powder fire extinguishers, halothane fire extinguishers, carbon dioxide fire extinguishers and so on. Electrified fire, including household appliances, electronic components, electrical equipment (computers, copiers, printers, fax machines, generators, motors, transformers, etc.) and wires and cables, such as combustion is still electrically charged fire, while the top, wall-mounted daily lighting fixtures and fire can be cut off after the fire of the fire occurred after the power supply of the equipment should not be included in the scope of the electrified fire. Dry powder fire extinguishers can be used to fight Class F fires. According to June 26, 2007, the Ministry of Public Security issued the "Notice on Adjustment of Fire Class Standard". The new fire rating standards from the original three levels of large fires, major fires, general fires adjusted to four levels of special major fires, major fires, large fires and general fires. ① special major fires, causing more than 30 deaths, or more than 100 people seriously injured, or more than 100 million yuan of direct property damage; ② major fires, causing more than 10 people less than 30 deaths, or more than 50 people more than 100 people less than serious injuries, or 50 million yuan more than 100 million yuan of direct property damage; ③ large fires, causing more than three people less than 10 deaths (iii) Large fires are those that cause more than 3 deaths and less than 10 injuries, or more than 10 people and less than 50 serious injuries, or more than 10 million yuan and less than 50 million yuan of direct property damage; (iv) General fires are those that cause less than 3 deaths, or less than 10 serious injuries, or less than 10 million yuan of direct property damage. (Note: "above" includes this number and "below" does not include this number.) .
5. What are the safety precautions for the use of hydrogen
Safety precautions for the use of hydrogen: (1) hydrogen production, use and storage and transportation should be in line with the "Regulations on the Safe Management of Hazardous Chemicals" and "Regulations on the Supervision of the Safety of Special Equipment" of the relevant provisions.
(1) Hydrogen is a colorless, odorless, flammable and explosive gas. Hydrogen containing chlorine, oxygen, carbon monoxide and air and other mixtures have explosive hazards.
Due to the low ignition point of hydrogen, high explosive energy, so in the production, use and storage and transportation should pay close attention. The following are the explosion limits of these mixtures: 1) hydrogen and chlorine 1 : 1 (v/v) mixture, in the light can be exploded.
2) hydrogen and oxygen mixture explosion limit for oxygen containing hydrogen volume fraction of 4% ~ 95% 03) hydrogen and carbon monoxide mixture explosion limit for carbon monoxide containing hydrogen volume fraction of 13.5% ~ 49%.
4) hydrogen and air mixture explosion limit for air containing hydrogen volume fraction of 45% ~ 75%. (2) hydrogen accumulation in the room, when the content reaches the explosion limit there is a risk of explosion.
In the hydrogen atmosphere, there is a risk of asphyxiation. Therefore, ventilation should be installed in places where hydrogen is likely to leak or the hydrogen content is likely to increase, and hydrogen alarms should be installed to monitor the hydrogen content if necessary.
(3) Before overhauling or handling hydrogen piping, equipment, cylinders, etc., it is necessary to replace the hydrogen content with nitrogen (or other methods) to meet the fire regulations before starting work. (4) Hydrogen leakage from the cylinder nozzle or rapid discharge is a fire hazard, therefore, when the bottled hydrogen is shipped, ensure that the nozzle and valve are leak-free and tighten the cap; when using the bottled hydrogen, the valve should be opened slowly.
6. Fire safety tips for elementary school students
First, what should you do when you find a fire?
The discovery of fire to shout, or hit the basin, aluminum pots and other things that can make a sound, call more people to participate in the fire, and quickly call the phone "119" to the fire department alarm. Dial "119" should pay attention to the following details:
1, "119" fire alarm phone (preferably with a landline), be calm and collected, hear the dial tone, and then dial 119 number.
2, after the phone is connected, you should clearly state the address of the fire (including the name of the road, street, alley name, door number).
3, as far as possible to tell what material fire and the scope of the fire, as well as the number of people trapped.
4, calmly answer the "ll9" switchboard communications staff questions.
5, after the phone hangs up, should be sent to meet the fire truck at the intersection.
Second, the three elements of the fire
1, downwind fire, in order to prevent being burned by the fire.
2, the root of the fire, the effect is the most thorough.
3, 2 - 3 meters from the root to extinguish the fire, the best distance. The effective distance of the fire extinguisher is only 4.5 meters.
Third, the use of portable dry powder fire extinguishers
1, put the fire extinguisher on the ground, the left hand to support the neck of the bottle, with the right hand index finger hooked to the safety pin, gently a pull. The left hand can not be hard to grip the handle.
2, pick up the cylinder, the left hand to hold the bottom of the bottle, the right hand to squeeze the handle.
3. When extinguishing the fire, the cylinder should be tilted downward by 45 degrees.
4, the cylinder pressure gauge pointer points to the red *** domain, indicating that the fire extinguisher failure, pointing to the yellow, green *** domain can be used normally.
Fourth, the water can not put out which material fire?
1, alkali metals can not use water to fight. Because water and alkali metals (such as potassium, sodium metal) can make water decomposition and generate hydrogen and release a lot of heat, easily cause an explosion.
2, carbonized alkali residual genus, hydrogenated alkali can not use water to fight, such as potassium carbide, sodium carbide, aluminum carbide and calcium carbide, as well as potassium hydroxide, magnesium chloride can be a chemical reaction in the presence of water, releasing a lot of heat, which may cause a fire and explosion.
3, lighter than water and insoluble in water flammable liquids, in principle, not the town of water to fight.
4, molten iron, steel can not be used to fight. Because of the iron, steel temperature of about 1600 ℃, water vapor at 1000 ℃ above the decomposition of hydrogen and oxygen, there is a risk of explosion.
5, three acids (sulfuric acid, nitric acid, hydrochloric acid) can not use a strong water to fight, if necessary, can be used to spray water to fight.
6, high-voltage electrical device fire, in the absence of good grounding equipment or cut off the current, generally can not use water to fight.
Fifth, the fire should follow the "three save" principle
1, smoke. Cover the mouth and nose with a wet towel 3 - 8 layers (can only prevent 3 - 5 minutes), there are no conditions can be sprinkled on the clothes on the urine to prevent smoke.
2, grasp the direction of escape. In the event of a fire, the use of smoke is not thick or fire has not yet burned the stairs, evacuation channel, open staircase escape is the most ideal choice. But in the reach or the environment is not familiar with the situation, hurry to crawl from the ground to find the wall, along the wall to find the door (clockwise, counterclockwise direction can be), escape from the door.
3, with the help of tools to escape, three layers of fire should be timely use of the rope (or the window city, bed sheets torn into thicker strips of long bands), will be firmly tied to the water pipe or heating pipe and other objects that can load the weight of the other end from the window down to the ground or the lower floors of the balcony, and then slide down along the rope, to escape from the fire. 4 - 6 layer of fire can be used to escape from the fire. -6 floor fire can be used with the help of a fire hydrant to escape.
Six, fire escape "seventy-two words mnemonic" specific content
Familiar with the environment, the exit is easy to find; found that the fire, the alarm should be early; remain calm, orderly escape; simple protection, creeping and bending; careful into the elevator, change the hallway; slow descent to escape, do not wait and do not rely on; fire has been and the body, do not run; trapped indoors, the good thing to stay; escape from danger! The first thing you need to do is to keep your eyes open and keep your head down.