How does chemical reaction works?

Answer 1

The Firework-Part I. First, let's define our firework. It is a 4", 12 ga steel tube with two separate chambers except for a 1/8" hole between them and it is fitted with fins and a 2" long, 1/4" i.d. piece of tubing, a rocket nozzle and a fuse. Both chambers are filled with a mixture of fine, dry, chemicals, but mixed in with the chemicals in the top chamber are BB-sized spheres of several flammable chemical elements. The bottom chamber contains the right amount of propellant to launch the firework about 1000 ft into the air. This happens when the lit fuse reaches the chemicals, which then burn rapidly to produce smoke and hot gases. The hot gases and particles of smoke exiting the rocket nozzle at high velocity are what cause the firework to be propelled into the air according to Newton's Third Law of Motion. When the firework reaches approximately 1000 ft, the last bit of burning propellant reaches the hole between the two chambers and ignites the dry, powdered chemicals in the top chamber. This chemical mixture reacts so fast that it only burns for a few seconds before it explodes, and when it does, the hot, solid spheres burn from the oxygen in the air as they are ejected outward in all directions.

Chemical Energy. The way that chemical energy works in fireworks and in almost all explosive compounds and mixtures is paradoxical. This will be explained shortly, but first: What is "chemical energy?" Where does it come from and how does it cause rockets from NASA or our firework to lift into the air and, in the case of our firework, explode? Into what kind of energy is the chemical energy transformed?

Conservation of Energy. Remember that energy cannot be destroyed or created, it can only change forms, including when matter is converted into energy according to Einstein's famous equation E=m·c2. Matter is only converted into energy in a star, a nuclear reactor, in a nuclear bomb or during radioactive decay. None of those things is involved with setting off a firework, but I think it's cool to imagine that the amount of matter plus energy present in the entire universe today is exactly the same as it was 13.8 billion years ago right after the universe was created.

Energy in Chemical Bonds. Chemical energy is one type of potential energy. It is the energy associated with chemical bonds; in particular, it is the energy required or liberated when a specific chemical bond is broken or formed. The magnitude of the energy is the same whether a specific bond is broken or formed, but the energy is negative in one case and positive in the other. The convention is that when energy is given off its value is negative, and when energy is required its value is positive. In nearly all cases, energy is required to break a chemical bond, and energy is liberated when a chemical bond is formed. However, most "unstable" compounds, such as acetylene, contain at least one bond that gives off energy when it is broken. This is discussed in the next paragraph. When our firework lifts off then explodes, some of the potential chemical energy has been transformed into kinetic energy; energy associated with an object's motion. It is obvious the firework has kinetic energy as it is in motion, but don't forget about the particles of smoke and the gases being ejected from the rocket nozzle and the metal pieces that will be sent flying due to the explosion. The chemical energy is also transformed into light, heat, sound and potential kinetic energy as the firework rises against the Earth's gravitational field. Lastly, the products of the chemical reactions in our firework have chemical bonds which means that a portion of the initial chemical energy stored in the chemical bonds of our mixtures remains in the chemical bonds of the smoke and gases produced when the chemical mixtures reacted.

Stable Chemical Compounds. Compounds said to be "stable" stay around for a long time without changing under conditions of normal temperatures and pressures and without being subjected to abnormal levels or frequencies of electromagnetic radiation. Let's look at water as an example. Water is a very stable chemical compound because the energy required to break either of its two equivalent oxygen-hydrogen (O-H) bonds is close to the energy needed to break an O-H bond in other known compounds. Either O-H bond in water will only break if it absorbs more energy than was released when the bond was formed, and that amount of energy is not available under normal conditions. The bonds can be broken if water is heated to a high enough temperature, but that can only be done if gaseous water is under a lot of pressure. One of the easiest ways to break down water into hydrogen and oxygen gasses is to pass an electric current through it. Salted water is a good conductor of electricity. Hydrogen and oxygen gas can be produced by placing two wires, one from each pole of a battery, into a container of salt water. When this is done, one will see tiny bubbles coming off of each wire and one wire will be giving off more bubbles than the other one. (Which gas is being produced in the greater amount?) Warning! DO NOT attempt this experiment unless you are an adult with supervised laboratory experience using voltage sources. The experiment is normally very safe, however using an automobile battery or trying to use electricity from a wall socket is extremely dangerous and has the potential of causing severe injury or death. I have found that the rectangular 9V radio batteries have the best combination of safety and results.

Chemical Energy Paradox. Okay, we now know what chemical energy is and that it comes from breaking or forming chemical bonds, but how does it lift up our firework? The paradox is that in almost all cases, including our firework, virtually every bond in each chemical compound making up both of our chemical mixtures must be broken in order for the mixtures to give off enough energy to lift our firework and then make it explode. But how can this be when for almost every stable compound energy is required, not given off, when chemical bonds are broken? The answer is twofold: 1) One must compare the energy and number of new chemical bonds formed during the chemical reaction with the energy and number of bonds broken during the reaction. Since our firework does work and gives off energy, the energy given off by the number of newly-formed bonds must be greater than the energy it took to break all of the bonds. 2) Only a very small fraction of the total number of bonds that must be broken is required before new bonds are formed. The heat supplied by the fuse is absolutely necessary to break some bonds in the beginning, but when enough new bonds are formed, a sufficient amount of heat is evolved to sustain the reaction with plenty of heat left over.

Our Firework's Chemicals. I don't know about you, but I'm ready to shoot off our firework! Most chemical reactions are oxidation-reduction reactions, and that type of reaction will be used to get the firework into the air and cause it to explode, sending out colored sparks in every direction. For the propellant, I decided to use the same oxidant and fuel that NASA used in the Space Shuttle's solid fuel rocket boosters. The oxidant is ammonium perchlorate [(NH4)(ClO4)] and the fuel is finely-divided aluminum (Al). Neither the reaction products nor their relative amounts were given on a NASA website, but I was able to figure them out and I am certain that my balanced chemical equation is correct. I will not share the balanced chemical equation in this forum for safety reasons. If you are not a professional chemist educated about stoichiometry, moles, normalization and exactly what safety equipment to use, then please do not attempt to make or ignite any type of propellant. If you are interested in rocketry, most larger cities have a club. In time and with the right training you will be able to safely prepare propellants and launch your own rockets. The chemicals used for various propellants are on numerous websites, although procuring them would not be easy these days and some are almost certainly illegal to possess. Nothing I am providing here cannot be found in many other places, and in addition, seeing the products of the reaction is an important part of the answer to the question. The unbalanced chemical equation is:

Al + (NH4)(ClO4) -----> Al2O3 + H2O + N2O + Cl2.

Both N2O and Cl2 are powerful oxidizing agents. In the actual Space Shuttle solid rocket fuel, these two oxidants react with the binder used to make the fuel a soft, plastic-like material rather than a free-flowing powder. From the equation, I hope that you can see why the reaction releases a lot of energy. Aluminum oxide is an extremely stable compound, and as such a huge amount of energy is liberated when it is formed. Water and nitrous oxide are also very stable, much more so than ammonium perchlorate, which is very reactive. Thus, a substantial amount of energy is released when the Al-O, O-H, N-O and Cl-Cl bonds are formed.

Predictions from a Chemical Equation. Even though it is unbalanced, the chemical equation above suggests that Al and ammonium perchlorate would make an excellent propellant (or explosive). What it does not divulge is the reaction rate; yes there are computer models, but in reality, how rapidly an oxidant and a fuel react is determined empirically and that is the reason mixing a powerful oxidizing agent with a good fuel is so dangerous. The reason our propellant is so effective is because the reaction converts two solid reagents into three gaseous compounds such that there is a very large volume increase. That gives rise to a vast increase in pressure that will usually result in an explosion unless there is an outlet for the gasses produced. The higher the pressure and temperature, the higher the velocity of the species ejected from the nozzle and the greater the specific thrust, provided that the nozzle geometry has not changed. Thanks to the heat released during formation of the reaction products, primarily aluminum oxide, the water produced in the reaction is in the gas phase. One last advantage of the fuel is that the average particle size of the Al can be controlled. This allows the burn rate of the propellant to be varied, within bounds, and it can probably make the difference between a chemical mixture that burns and one that explodes.

The Firework-Part II. Finally, a few sentences about the second chemical mixture. Some commercial fireworks use relatively small quantities of a high explosive (a single chemical compound like TNT or PETN) in the explosive stage of the device because the sound of the explosion is many times louder and it disperses the sparks further out from the center. There are quite a few mixtures that will explode, however their burn rates are much too slow to rank them as "high explosives." The explosive in our firework was a very fine powdered mixture of an active metal, an oxidant similar to ammonium perchlorate, and nitromethane to which small spheres of calcium, aluminum, bismuth, magnesium, zinc and iron were added. The surfaces of the small spheres of the metals and bismuth would get extremely hot when the explosive powder burned for a few seconds, at most, before exploding.

The Launch. Last Fourth of July night, my wife and I went out in the country and set things up in a huge cut wheat field. The firework sled was a 1/8" x 5' long steel rod welded to the edge of a 1/4" thick piece of circular steel that was 8" in diameter. I inserted a long piece of fuse through the firework's nozzle until it was no more than 1/2" into the propellant and lit it. We stood about 30 yards away just in case the propellant burned too fast, however I was confident that it would work fine since it was close to the same propellant used in the Space Shuttle's solid fuel rocket boosters.

About two seconds after the flame from the lit fuse disappeared, the firework roared to life. I thought that it was going to sit there on that steel plate forever, just blowing a very smoky, white hot circle of fire a good ten feet wide, but it actually only sat for a couple of seconds before it began to rise, slowly at first, as the howl from the rocket motor gathered volume. Once the device rose to the top of the guide rod, it really began to accelerate, and it was approximately 1,100 ft high when the huge tongue of murky fire disappeared. About one second later the invisible device reappeared as a huge and brilliant yellow fireball, out of which speeding pieces of light of various colors appeared, headed in all directions. Using the stopwatch feature on my cell phone, I did my best to measure the time between the appearance of the burst of light and the earsplitting blast of baritone sound. The time difference was 0.988 seconds, confirming that the eruption of sound was very nearly 1,100 ft distant. What a show. I'm looking forward to next July 4!

Disclaimer: Although the technical details and scientific facts and concepts presented in the answer I provided here are true and accurate, the plot presented here is completely fictitious. It was included as part of my answer in an attempt to maintain the reader's interest and to facilitate his comprehension of the physical and chemical information necessary to completely understand the thorough answer provided.

Answer 2

You'll need to be more specific. There are lots of different kinds of reactions that work in different ways.

How does a chemical rection take place in the body?

Answer 3

chemical energy works by eating

Answer 4

chemical energy is an energy