Oh in this video looking a look at the harbour process which is the industrial production of ammonia from nitrogen and hydrogen and in particular we'll consider why the reaction is always done at a temperature of 450 degrees Celsius and a pressure of 200 atmospheres alongside an iron catalyst the reason everyone learns about the harper process is that it's one of the most important reactions in the world this is because the ammonia that it reduces is used to make nitrogen based fertilizers which allows to grow all of the food that we need to feed everyone in order to make such huge amounts of ammonia though we need a massive amount of nitrogen and hydrogen the nitrogen is easy to acquire because 78% of the air all around us is nitrogen so we just take it from there how did you know is a bit tricky to get hold of as we have to make it from hydrocarbons like methane now two important things to notice about this reaction are that it produces heat which means it's exothermic and that it has a two way reaction error which means it is reversible so some of the ammonia that gets formed will break back down to reform a nitrogen and hydrogen you the next thing means to look at is how the process works and for that is helpful choose a diagram of the machines that they use it doesn't look quite like theirs in your life but the basic idea is the same the first step is to take the hydrogen and nitrogen layer using as reactants and feed them into the top left of the machine where they can mix together we call this first part they reaction a vessel and it's where the conditions are kept at 450 degrees Celsius and 200 atmospheres and the gases are free to pass over this iron catalyst under these conditions some of the nitrogen and hydrogen react together to form ammonia but importantly because it's a reversible reaction the mixture will still contain lots of nitrogen and hydrogen this means that we need to somehow separate the ammonia that's been formed from the nitrogen and hydrogen that haven't reacted luckily ammonia has a fairly low boiling point and so by passing the entire mixture through this pipe into the condenser which is much colder than the reaction vessel we can cool down the gaseous ammonia until it condenses into liquid ammonia whereas the gaseous nitrogen and cases hydrogen will stay gaseous because they have higher boiling points and so they can be recycled back around into our reactant mixture now that we know how it works the last thing we need to cover is why the harbor process uses the conditions of 450 degrees and 200m aspheres and as we consider each condition we need to bear in mind three things the percentage yield the rate of the reaction and any practical things like cost let's start with temperature because the reaction is exothermic we're going to need a low temperature in order to favour the forward reaction and achieve a higher percentage yield the problem though is that in order to achieve a higher rate of reaction we need a high temperature because the particles need plenty of kinetic energy in order to react as a consequence 450 degrees is chosen as a compromise even though it gives us a lower yield it causes a higher rate of reaction finally generating heat is expensive so using a higher temperature would be too costly if we turn to pressure in order to achieve a high percentage yield of ammonia we're going to want a high pressure because there are fewer molecules of gaseous product and there are reactants so a high pressure will push the equilibrium to the right we also want a high pressure to achieve a high rate of reaction because high pressures mean that the particles collide with each other more frequently and so can reactive or in this case both of the points indicate that we need a high pressure so the only thing limiting how high we make the pressure are the practical considerations like cost and safety maintaining a high pressure is very expensive and if anything goes wrong high pressures can be really dangerous and so true hundred atmospheres turned out to be the best pressure anyway that's everything for this video so hope you enjoyed it and we'll see you again soon you