Lesson video

Hello, my name is Mrs. Collins and I'll be taking you through the learning today.

This lesson forms part of the unit industrial chemistry and is called MPK, fertilisers, agriculture, and other applications.

During today's lesson, you will describe applications of industrial chemistry in agriculture, specifically in the production of ammonium salts for fertilisers.

Here are the key words for today's lesson, fertiliser, eutrophication, salt, batch process, and continuous process.

Pause the video here, read through those explanations and make any notes you feel you need to.

Today's lesson is divided into three parts, applications of ammonia, laboratory production of ammonium salts, and industrial production of ammonium salts.

So let's start with applications of ammonia.

You'll know from your previous learning that ammonia is a simple molecular substance.

Each molecule is made of one nitrogen atom and three hydrogen atoms, and we can show that in a displayed formula or a ball-and-stick model.

The global ammonia market is estimated to be well over 150 million pounds with roughly 200 million tonnes produced each year.

It's produced in the harbour process, remember? And is an important feedstock for the production of explosives, polymers, dyes, cleaning products, and fertilisers.

And it's the last application there that we are interested in today.

So here is a question based on that learning.

Ammonia is used only in the production of fertilisers.

Is that true or false? And then justify your answer underneath.

So pause the video here, answer the question, and I'll see you when you're finished.

Welcome back, so the answer is false.

Ammonia is used in the manufacture of fertilisers, explosives, plastics, dyes, and cleaning products.

So well done if got that correct.

So fertilisers improve the growth of crop plants like wheat.

They can be natural, for example, manure, or synthetic mixtures, formulations of soluble chemicals added to the soil.

Fertilisers containing nitrogen, phosphorus, and potassium are very common as these elements promote plant growth.

And they're therefore known as NPK fertilisers.

Fertilisers replace minerals that have been used up by plants and help prevent deficiency diseases.

And farmers use fertilisers not only to increase the crop yields, but keep them at consistent levels year on year.

And here are some examples of deficiency diseases in plants that are caused when there's a lack of these particular minerals.

So you can see there nitrogen, phosphorus, and potassium deficiencies.

Here's a question based on that learning.

Which of the following elements are most commonly found in NPK fertilisers to promote plant growth? So pause the video here, answer the question, and I'll see you when you're finished.

Welcome back, so the N stands for nitrogen, the P for phosphorus, and the K for potassium.

So well done if you've got that correct.

Nitrogen has many important uses in plants, mostly in the production of chlorophyll and protein synthesis.

Common nitrogen compounds using fertilisers include ammonium nitrate and urea.

So here we've got a plant and we're gonna talk through some of the uses here of that particular mineral in this plant.

So chlorophyll is the green part of the plants, remember from your biology lessons, and this is where photosynthesis takes place.

And chlorophyll is partly made up of the element nitrogen.

Protein makes up all living things and is stored in the fruit, grains or seeds of plants and nitrogen helps to regulate plant growth and development.

It's important to the structure of the plant.

And lastly, nitrogen is found in proteins and enzymes in the roots.

Nutrients and water are taken up through the roots.

So basically, nitrogen is really important because it's found in proteins, and enzymes are made of proteins and it's found in chlorophyll, so they're the two big applications or uses of nitrogen in plants.

Phosphorus is needed by plants for energy transfer, root development, and flowering.

Ammonium phosphate is the most common phosphorus compound added to fertilisers.

So here again, if we look at the plant, phosphorus is essential in photosynthesis.

It improves seed production, flower formation, and early crop maturity.

It's an essential part of DNA, and it's essential for cell division and the growth of new tissues.

Phosphorus stores energy as ATP and it stimulates root development.

Potassium is crucial for water regulation, enzyme activation, and disease resistance.

Common potassium compounds using fertilisers are potassium chloride and potassium sulphate.

Both of these compounds are obtained through mining and are soluble water, so it can be added straight to the fertiliser mixtures.

So back to the plant again, it's known as a quality nutrient as it helps improve physical qualities of the plants, increases resistance to diseases and low temperatures.

It increases plant health, is essential for forming sugars and starch, is linked with the movement of water, nutrients and carbohydrates in plants, and it promotes healthy roots.

Here's a question based on that learning, which of the following elements are added to fertilisers for the production of chlorophyll? So pause the video here, answer the question, and I'll see you when you're finished.

Welcome back, so the answer to that question is nitrogen.

So well done if you got that correct.

Second question, ammonium phosphate provides which elements when added to the fertilisers? So have a look at ammonium phosphate and think carefully about what might be present there.

Pause the video here, answer the question, and I'll see you when you're finished.

Welcome back, so the answer is nitrogen and phosphorus.

So well done if you got that correct.

Eutrophication occurs when excessive fertilisers run off into water bodies, leading to nutrient overloading.

So imagine you've spread the fertiliser onto your field.

Then there's been heavy rainfall, and that's washed off into water bodies, that's things like lakes, rivers, streams, et cetera.

This promotes the growth of algae on the surface and causes algal blooms. And what the algal blooms do is deplete the oxygen in the water and that harms aquatic life, so things like fish, and disrupts the ecosystem.

So you can see the algal bloom growing there on the surface of the water.

So there's too many nutrients in the water probably due to fertilisers being runoff into the water.

Preventing eutrophication involves managing fertiliser application and implementing buffer zones near water bodies to reduce runoff.

So a buffer zone is an area close to the water where you don't put fertiliser.

So a buffer zone is a vegetated area near water bodies that helps absorb nutrients, filter pollutants, and reduce runoff, thereby protecting the water quality.

So it'd be worth pausing the video here and just absorbing the information that's in that diagram.

Ammonium salts can also play a role in water purification processes by removing unwanted ions and contaminants.

Handling and storage of ammonium salts must be done with care to prevent hazards such as explosions, particularly with ammonium nitrate.

Here's a question based on that learning.

Which of the following are potential issues relating to the use and storage of ammonia products? Pause the video here, answer the question, and I'll see you when you're finished.

Welcome back, so let's have a look at the answers to that question.

We've got eutrophication of water bodies, and safe storage and handling challenges.

So well done if you got that correct.

We're now going to do task A.

Give an advantage for the use of synthetic fertilisers for crop plants and a disadvantage of their use.

Two, below are some chemicals proposed for use in fertilisers.

Which compounds would be added to create a mixture that would be beneficial for healthy plant growth? So think about those three elements that are really important for plants, and then consider your answer.

Pause the video here, answer the questions, and I'll see you when you're finished.

Welcome back, so let's have a look at some of those answers then.

So an advantage for the use of synthetic fertilisers for crop yields, your answer might include, replenishes the soil with minerals needed for plant growth, consistent and predictable nutrient composition.

And some of the disadvantages, overuse of fertilisers can lead to eutrophication and harming aquatic life and it increases costs for farmers.

So well done, if your answer looks something like that.

Question two, a good fertiliser contains a mixture of the salts that contain all three of NPK.

So that's nitrogen, phosphorus, and potassium.

Salts A, B, and E are all salts that would be beneficial to the healthy growth of plants.

Chemical D and F do contain useful elements, but they are corrosive substances.

These would change the pH of the soil and damage the crops.

Chemical C is also corrosive, but does not contain any useful NPK elements.

So if we look very carefully back at that, so D is potassium hydroxide, and F is phosphoric acid.

Now, moving on to part two of the lesson, laboratory production of ammonium salts.

Chemists will devise ways to make chemicals synthetically first in a laboratory before mass production.

Ammonium salts can be produced in a laboratory by reacting an acid with ammonia using titration, evaporating the solution and collecting the crystals of ammonium salts.

This is called a batch process.

Ammonia is reactive with nitric acid to make ammonium nitrate.

So here we've got the equation for that.

Now, we need to think about where the ammonia has come from.

So remember, we normally extract this currently from natural gas.

So we take the methane from natural gas and react that with steam, that forms carbon dioxide and hydrogen.

We take the hydrogen from that reaction and react it with nitrogen, which we take from the air to form ammonia.

That ammonia, we then react with oxygen and water to form nitric acid.

And then the nitric acid, we can react with ammonia to form ammonium nitrate.

So ammonia is reactive with sulfuric acid to make ammonium sulphate.

So we've got ammonia and sulfuric acid forming ammonium sulphate.

So we get the ammonia from the harbour process and the sulfuric acid using the contact process.

So here, we've got sulphur and oxygen and water through that contact process, producing sulfuric acid.

That sulfuric acid is then reacting with the ammonia that we produce via the harbour process to produce ammonium sulphate.

Ammonia is reactive with phosphoric acid to make ammonium phosphate.

So we've got ammonia plus phosphoric acid, forming ammonium phosphate, and this is the process to make phosphoric acid.

So you can see, it's quite a complex process involving phosphate rock, sand, air, water, sand filters, et cetera.

Task B, describe the steps involved in making pure dry salt crystals from ammonia and sulfuric acid in the lab.

Include the apparatus used, name the salt produced, and write a balanced symbol equation giving state symbols.

So pause the video here, answer the question, and I'll see you when you're finished.

Welcome back, so include the apparatus used.

You need to have a known volume and concentration of ammonia solution added to a conical flask.

From a burette, a known concentration of sulfuric acid can be added to be completely neutralised.

The neutral solution formed can be transferred to an evaporating dish left to crystallise, and any remaining solvent can be removed by drying crystals in an oven or dabbing dry with a filter paper.

So you can see, we've used the equipment there in the explanation.

We haven't just written a method without the equipment named.

Name the salt produced.

So the salt produced between ammonia and sulfuric acid is ammonium sulphate, and there is the balanced symbol and word equation for that reaction with the state symbols.

So I want you to potentially pause the video here, and just check to make sure your equation is the same as the one given there on screen.

So well done if you got that correct.

We're now moving on to part three of the lesson, industrial production of ammonium salts.

After a synthesis root has been devised in the lab, this is then scaled up and optimised to be used in industrial processing.

This typically increases efficiency of the process.

So in industry, phosphate rock is used, ammonia and the acid will be made on site.

The production of ammonium salts is called a continuous process when it's done in this way.

During a batch process, we add the raw materials.

Those raw materials react together over a period of time, and then we remove the product at the end.

For a continuous process, we are continually adding raw materials and constantly removing the product, so it's happening continuously over time.

Hydrogen and nitrogen are reacted together in the harbour process to make ammonia.

Ammonia is used to make both nitric acid and ammonium nitrate, and nitric acid is synthesised from ammonia over multiple stages.

Overall, the reaction can be shown like this.

So we have ammonia reacting with oxygen to form nitric acid and water.

Phosphate rock, which is mostly calcium phosphate is a type of sedimentary rock that is insoluble.

So we can't use it as a fertiliser because we need it to dissolve in water so that it can be absorbed by the plants up through the roots.

So what we do is we mine the rock and then we chemically treat it.

This produces a soluble phosphate compound that we can use in the production of ammonium phosphate.

Phosphate rock can be treated with nitric acid to make phosphoric acid and calcium nitrate, which is shown there in the equation.

And phosphate rock can be treated with sulfuric acid to make a single, what we call a super phosphate.

So it was the first commercially available mineral fertiliser.

So there we got calcium phosphate, calcium sulphate being produced in that reaction.

Phosphate rock can be treated with phosphoric acid to make triple super phosphate.

So we've got phosphoric acid reacting with a phosphate rock to form calcium phosphate, as you can see there.

So here's a question based on that learning.

It's a true or false question.

Phosphate rock is added to synthetic fertilisers.

Is this true or false? And justify your answer using the statements.

Pause the video here, answer the question, and I'll see you when you're finished.

Welcome back, so the answer to that question is false, and this is because phosphate rock is a primary source of phosphorus, which is used in the production of synthetic fertilisers.

Second question, how does the laboratory preparation of ammonium salts differ from industrial preparation? So pause the video here, answer the question, and I'll see you when you're finished.

Welcome back, so the answer is, laboratory preparation uses smaller quantities of chemicals.

Industrial preparation involves continuous production processes.

And industrial preparation uses larger scale equipment and automation.

So well done if you got that correct.

Now, we're going to do task C.

Complete and balance the equation, and then use the information sheet to complete the table below.

Pause the video here, make sure you've got a copy of the information sheet, prepare your answer, and I'll see you when you're finished.

Welcome back, so let's go through those answers then.

So there's the balanced symbol equation for this reaction.

So you may want to pause the video and just check that against your answer.

Well done if you've got that correct.

Here's a potential answer to question two.

So the batch type, we've got laboratory is batch, industrial is continuous.

Quantity of reactants, small and large, and that was given at the start.

Then steps involved for laboratory, you've got titration, then crystallisation, whereas industry has got many steps involved.

The concentration of the reactants is dilute for batch and concentrated for industry.

The main reaction type is neutralisation for both.

The crystallisation process is slow heating and air drying for laboratory and a heated tower with air blown for uniform granules in industry.

And the apparatus needed in laboratory is glass, and in industry is strong and reinforced heavy duty materials.

So well done if you got that correct.

Here's a summary of this lesson.

Fertilisers contain nitrogen, phosphorus, and potassium compounds to promote plant growth.

Ammonia is a feedstock for manufacturer of fertilisers, explosives, plastics, dyes, and cleaning products.

Ammonia can be used to manufacture ammonium salts and nitric acid.

Phosphate rock is used in the production of fertilisers.

And the laboratory preparation of ammonium salts is not the same as the industrial preparation.

So laboratory preparation is generally batch and industrial preparation is continuous.

Thank you very much for joining me for today's lesson.