9:59:59.000,9:59:59.000 What would you say 9:59:59.000,9:59:59.000 is the most important discovery 9:59:59.000,9:59:59.000 made in the past few centuries? 9:59:59.000,9:59:59.000 Is it the computer? 9:59:59.000,9:59:59.000 The car? 9:59:59.000,9:59:59.000 Electricity? 9:59:59.000,9:59:59.000 Or maybe the discovery of the atom? 9:59:59.000,9:59:59.000 I would argue that it is this chemical reaction: 9:59:59.000,9:59:59.000 a nitrogen gas molecule 9:59:59.000,9:59:59.000 plus three hydrogen gas molecules 9:59:59.000,9:59:59.000 gets you two ammonia gas molecules. 9:59:59.000,9:59:59.000 This is the Haber process 9:59:59.000,9:59:59.000 of binding nitrogen molecules in the air 9:59:59.000,9:59:59.000 to hydrogen molecules, 9:59:59.000,9:59:59.000 or turning air into fertilizer. 9:59:59.000,9:59:59.000 Without this reaction, 9:59:59.000,9:59:59.000 farmers would be capable of producing enough food 9:59:59.000,9:59:59.000 for only 4 billion people; 9:59:59.000,9:59:59.000 our current population is just over 7 billion people. 9:59:59.000,9:59:59.000 So, without the Haber process, 9:59:59.000,9:59:59.000 over 3 billion people would be without food. 9:59:59.000,9:59:59.000 You see, nitrogen in the form of nitrate, NO3, 9:59:59.000,9:59:59.000 is an essential nutrient for plants to survive. 9:59:59.000,9:59:59.000 As crops grow, they consume the nitrogen, 9:59:59.000,9:59:59.000 removing it from the soil. 9:59:59.000,9:59:59.000 The nitrogen can be replenished 9:59:59.000,9:59:59.000 through long, natural fertilization processes 9:59:59.000,9:59:59.000 like decaying animals, 9:59:59.000,9:59:59.000 but humans want to grow food 9:59:59.000,9:59:59.000 much faster than that. 9:59:59.000,9:59:59.000 Now, here's the frustrating part: 9:59:59.000,9:59:59.000 78% of the air is composed of nitrogen, 9:59:59.000,9:59:59.000 but crops can't just take nitrogen from the air 9:59:59.000,9:59:59.000 because it contains very strong triple bonds, 9:59:59.000,9:59:59.000 which crops cannot break. 9:59:59.000,9:59:59.000 What Haber did basically 9:59:59.000,9:59:59.000 was figure out a way 9:59:59.000,9:59:59.000 to take this nitrogen in the air 9:59:59.000,9:59:59.000 and put it into the ground. 9:59:59.000,9:59:59.000 In 1908, the German chemist Fritz Haber 9:59:59.000,9:59:59.000 developed a chemical method 9:59:59.000,9:59:59.000 for utilizing the vast supply of nitrogen in the air. 9:59:59.000,9:59:59.000 Haber found a method 9:59:59.000,9:59:59.000 which took the nitrogen from the air 9:59:59.000,9:59:59.000 and bonded it to hydrogen 9:59:59.000,9:59:59.000 to form ammonia. 9:59:59.000,9:59:59.000 Ammonia can then be injected into the soil, 9:59:59.000,9:59:59.000 where it is quickly converted into nitrate. 9:59:59.000,9:59:59.000 But if Haber's process was going to be used 9:59:59.000,9:59:59.000 to feed the world, 9:59:59.000,9:59:59.000 he would need to find a way 9:59:59.000,9:59:59.000 to create a lot of this ammonia quickly and easily. 9:59:59.000,9:59:59.000 In order to understand 9:59:59.000,9:59:59.000 how Haber accomplished this feat, 9:59:59.000,9:59:59.000 we need to know something 9:59:59.000,9:59:59.000 about chemical equilibrium. 9:59:59.000,9:59:59.000 Chemical equilibrium can be achieved 9:59:59.000,9:59:59.000 when you have a reaction in a closed container. 9:59:59.000,9:59:59.000 For example, let's say you put 9:59:59.000,9:59:59.000 hydrogen and nitrogen into a closed container 9:59:59.000,9:59:59.000 and allow them to react. 9:59:59.000,9:59:59.000 In the beginning of the experiment, 9:59:59.000,9:59:59.000 you have a lot of nitrogen and hydrogen, 9:59:59.000,9:59:59.000 so the formation of ammonia proceeds a high speed. 9:59:59.000,9:59:59.000 But as the hydrogen and nitrogen react 9:59:59.000,9:59:59.000 and get used up, 9:59:59.000,9:59:59.000 the reaction slows down 9:59:59.000,9:59:59.000 because there is less hydrogen and nitrogen 9:59:59.000,9:59:59.000 in the container. 9:59:59.000,9:59:59.000 Eventually, the ammonia molecules reach a point 9:59:59.000,9:59:59.000 where they start to decompose 9:59:59.000,9:59:59.000 into the hydrogen and nitrogen. 9:59:59.000,9:59:59.000 After a while, they two reactions, 9:59:59.000,9:59:59.000 creating and breaking down ammonia, 9:59:59.000,9:59:59.000 will reach the same speed. 9:59:59.000,9:59:59.000 When these speeds are equal, 9:59:59.000,9:59:59.000 we say the reaction has reached equilibrium. 9:59:59.000,9:59:59.000 This might sound good, but it's not 9:59:59.000,9:59:59.000 when what you want 9:59:59.000,9:59:59.000 is to just create a ton of ammonia. 9:59:59.000,9:59:59.000 Haber doesn't want the ammonia to break down at all, 9:59:59.000,9:59:59.000 but if you simply leave the reaction 9:59:59.000,9:59:59.000 in a closed container, 9:59:59.000,9:59:59.000 that's what will happen. 9:59:59.000,9:59:59.000 Here's where Henry Le Chatelier, 9:59:59.000,9:59:59.000 a French chemist, 9:59:59.000,9:59:59.000 can help. 9:59:59.000,9:59:59.000 What he found was 9:59:59.000,9:59:59.000 that if you take a system in equilibrium 9:59:59.000,9:59:59.000 and you add something to it, 9:59:59.000,9:59:59.000 like, say, nitrogen, 9:59:59.000,9:59:59.000 the system will work 9:59:59.000,9:59:59.000 to get back to equilibrium again. 9:59:59.000,9:59:59.000 Le Chatelier also found 9:59:59.000,9:59:59.000 that if you increase 9:59:59.000,9:59:59.000 the amount of pressure on a system, 9:59:59.000,9:59:59.000 the system tries to work 9:59:59.000,9:59:59.000 to return the pressure it had. 9:59:59.000,9:59:59.000 It's like being in a crowded room. 9:59:59.000,9:59:59.000 The more molecules there are, 9:59:59.000,9:59:59.000 the more pressure there is. 9:59:59.000,9:59:59.000 If we look back at our equation, 9:59:59.000,9:59:59.000 we see that on the left-hand side, 9:59:59.000,9:59:59.000 there are four molecules on the left 9:59:59.000,9:59:59.000 and just two on the right. 9:59:59.000,9:59:59.000 So, if we want the room to be less crowded, 9:59:59.000,9:59:59.000 and therefore have less pressure, 9:59:59.000,9:59:59.000 the system will start combining 9:59:59.000,9:59:59.000 nitrogen and hydrogen 9:59:59.000,9:59:59.000 to make the more compact ammonia molecules. 9:59:59.000,9:59:59.000 Haber realized that in order to make 9:59:59.000,9:59:59.000 large amounts of ammonia, 9:59:59.000,9:59:59.000 he would have to create a machine 9:59:59.000,9:59:59.000 that would continually add nitrogen and hygrogen 9:59:59.000,9:59:59.000 while also increasing the pressure 9:59:59.000,9:59:59.000 on the equilibrium system, 9:59:59.000,9:59:59.000 which is exactly what he did. 9:59:59.000,9:59:59.000 Today, ammonia is one of the most produced 9:59:59.000,9:59:59.000 chemical compounds in the world. 9:59:59.000,9:59:59.000 Roughly 131 million metric tons are produced a year, 9:59:59.000,9:59:59.000 which is about 290 billion pounds of ammonia. 9:59:59.000,9:59:59.000 That's about the mass 9:59:59.000,9:59:59.000 of 30 million African elephants, 9:59:59.000,9:59:59.000 weighing roughly 10,000 pounds each. 9:59:59.000,9:59:59.000 80% of this ammonia is used in fertilizer production, 9:59:59.000,9:59:59.000 while the rest is used 9:59:59.000,9:59:59.000 in industrial and household cleaners 9:59:59.000,9:59:59.000 and to produce other nitrogen compounds, 9:59:59.000,9:59:59.000 such as nitric acid. 9:59:59.000,9:59:59.000 Recent studies have found 9:59:59.000,9:59:59.000 that half of nitrogen from these fertilizers 9:59:59.000,9:59:59.000 is not assimilated by plants. 9:59:59.000,9:59:59.000 Consequently, the nitrogen is found 9:59:59.000,9:59:59.000 as a volatile chemical compound 9:59:59.000,9:59:59.000 in the Earth's water supply and atmosphere, 9:59:59.000,9:59:59.000 severely damaging our environment. 9:59:59.000,9:59:59.000 Of course, Haber did not foresee this problem 9:59:59.000,9:59:59.000 when he introduced his invention. 9:59:59.000,9:59:59.000 Following his pioneering vision, 9:59:59.000,9:59:59.000 scientists today are looking 9:59:59.000,9:59:59.000 for a new process of the 21st century, 9:59:59.000,9:59:59.000 which will reach the same level of aid