Hello and welcome to the lesson.

We're going to look at the rules around solubility of salts today.

My name's Mrs. Clegg.

This lesson's part of the unit making salts.

So let's get started.

Here's the outcome for today's lesson.

So by the end of it, you should feel much more confident in being able to remember and apply the solubility rules.

You'll know whether a salt formed is insoluble or soluble.

Here are today's key words, solubility, salt, soluble, precipitate, and insoluble.

I'd like you to listen out for those words during our lesson today.

You might like to pause the video and take some notes of what these words mean to help you throughout the lesson.

Today's lesson is divided into two parts.

We're going to look at the rules of solubility first, and then we're going to look at soluble and insoluble salts.

So let's get started with the first part.

So first of all, what does solubility mean? Can you remember? So solubility refers to the ability of a substance to dissolve in a solvent.

A substance that dissolves in a solvent, like water, is termed soluble, while one that does not dissolve is insoluble.

It is important to note, however, that whilst all salts have some solubility, some are more soluble than others.

To make it easy, what we're going to do is say that those salts, which don't easily dissolve, are insoluble.

So let's have a quick check.

A substance that dissolves in a solvent like water is said to be insoluble.

Is that true or is that false? Well done if you said false, and can you justify your answer.

Great, if you noticed it was B, if a substance dissolves, it means it's soluble.

Many common salts are soluble in water, and these include salts that contain sodium, potassium, ammonium, and nitrates.

Here we've got some sodium chloride crystals.

They'll be very familiar with you because sodium chloride is table salt.

And when we dissolve them in water, we get a sodium chloride solution.

These salts dissolve readily in water and that makes them quite important in chemical reactions.

Let's have a check which of these statements are true.

Well done if you said C and even better if you said D as well.

All common potassium salts are soluble in water and sodium nitrate is soluble in water.

Most common chlorides and sulphates are soluble in water, with some exceptions being insoluble.

And when you're gonna have a look at those, and you need to remember these.

So silver chloride, lead chloride, lead sulphate, barium sulphate, and calcium sulphate are insoluble.

Here's some copper sulphate crystals, which you might have seen in the laboratory.

And here's a copper sulphate solution.

Again, these salts dissolve readily in water, and so they're important in various chemical reactions.

Let's have a quick check again.

Which of the following chlorides is insoluble in water? We're just looking for one answer here.

Well done if you said silver chloride.

All the others are soluble.

Well done.

Certain carbonates and hydroxides are also soluble in water, especially those that contain sodium, potassium, and ammonium ions.

You've got some sodium hydroxide pellets, and when they dissolve in water, we get a sodium hydroxide solution.

Most other carbonates and hydroxides don't actually dissolve in water, so they would be termed insoluble.

So let's have a check.

Most carbonates and hydroxides do not dissolve in water.

Is that true or is that false? Well done if you said true.

And can you justify your answer? Well done if you said B or sodium, potassium, and ammonium carbonates, and hydroxides are soluble.

But most other carbonates and hydroxides are insoluble.

We're going to look at a table of the solubility rules now.

So these apply to water because remember we can have other solvents.

So there's a list of all the soluble compounds and a list of the insoluble compounds.

So you do need to know these.

So it might be worth pausing the video and taking some notes.

In a way, it's almost easier to remember the insoluble compounds, isn't it? So silver chloride, lead chloride, lead sulphate, barium sulphate, calcium sulphate, most carbonates, and most hydroxides.

Those are the insoluble compounds.

Let's have a quick check.

So which of the following salts are soluble in water? Well done if you said ammonium chloride, and even better if you said potassium nitrate as well.

Lead sulphate and calcium carbonate are insoluble in water.

So let's get ready for task A now.

So we've got four students discussing the solubility of salts.

I want you to read the statements and identify who is correct and then update any incorrect statements.

So pause the video and come back when you're ready.

Welcome back.

Let's see how you've done then.

So the correct statements came from Andeep and Sophia.

So Andeep said, "All salts containing sodium, potassium and ammonium ions are soluble in water." And Sophia, "All nitrates and most sulphates are soluble in water." So let's have a look at Lucas's statement.

That is incorrect because most carbonates and hydroxides are insoluble in water.

The exceptions, if you remember, were sodium, potassium and ammonium.

Everything else insoluble.

Laura, she says silver chloride and lithium chloride are insoluble in water, which is incorrect.

And the correct statement should be silver chloride and lead chloride are insoluble in water, but lithium chloride is soluble in water.

So you need to learn those solubility statements from that table that I showed you earlier on.

Let's have a look at question two.

Chemical substances can be written in words or as formulae.

When writing chemical formulae, state symbols are used to show what state each substance is in.

The following substances are added to water.

Write out the chemical formula for each substance and give the correct state symbol.

Pause the video, come back when you're ready.

So how did you do? Some harder than others maybe? So here are the correct answers.

So sodium chloride would be aqueous 'cause it's in solution, it's soluble.

Silver nitrate is also aqueous, that's its soluble.

Barium sulphate, remember is insoluble.

So that would be a solid.

Lead chloride is also insoluble, so that would be solid.

And ammonium carbonate is aqueous, that's in solution.

Ammonium ions are soluble.

And make sure the subscripts are very obvious there.

The ammonium ions, they're in brackets because there are two ammonium ions for every carbonate ion.

Let's have a look at the second part of our lesson now where we're going to look at soluble and insoluble salts in a little bit more detail.

How do we make them for a start? Well, we can make soluble salts by reacting an acid with an insoluble base.

So here we've got an insoluble metal carbonate being added to acid, and you can see that there's definitely a chemical reaction going on there 'cause we can see the effervescence, the bubbling happening.

And insoluble salts are typically formed through a reaction called a precipitation reaction.

And that involves two soluble salts reacting together.

So if we look here, we've got two colourless liquids reacting together to form a yellow precipitate.

Let's do a quick check.

Soluble salts are formed by combining two insoluble salts.

True or false? Well done if you said false.

And can you justify your answer? Well done if you said B.

Soluble salts are formed by reacting an acid with an insoluble base.

So we're gonna look at how to make a soluble salt now.

So acids are usually reacted with an insoluble substance using the following method.

So step one, we would add the powdered insoluble reactant to the acid, then we gently heat it to increase the rate of the reaction, continuously stir all the time.

Step three, we keep adding that insoluble reactant until we can see some of the unreacted powder is left over.

And that tells us that all the acid has reacted.

And then the next step is to filter the mixture to remove the excess solid.

And then we would heat the solution in an evaporating dish over a water bath.

So there you can see a beaker of water being heated and that's acting as a water bath.

We don't directly heat the evaporating dish because the solution might spit and the evaporating dish might shatter.

If we need to, we can dry the crystals by gently dabbing them with filter paper, or we can place it in a warm oven for the rest of the liquid to evaporate.

So let's have a look at a quick check.

How do you know when all the acid has reacted with the insoluble reactant? How do you know? Amazing if you said D.

We've got some unreacted powder left over 'cause all the acid has reacted.

Another question, which pair of solutions would you mix together to form potassium sulphate, which is a soluble salt? Well done if you said A, potassium hydroxide and sulfuric acid.

It can't be B or C because we need to make potassium sulphate.

And so hydrochloric acid wouldn't make potassium sulphate and neither would nitric acid.

So we're gonna have a look at how we make insoluble salts now.

Insoluble salts are prepared by reacting to soluble salts in a reaction known as a precipitation reaction.

So we mix the solutions of the two soluble salts together.

One of them will contain the desired positive ion, and the other contains the desired negative ion that we are looking to make for the insoluble salt.

And you can see where the two solutions are being poured into the beaker.

There you can see the solid precipitate forming in the beaker.

Then we need to filter the solution to separate the precipitate from the filtrate.

We would wash the precipitate with distilled water to remove any impurities from it.

So we're washing what the solid that's left on the filter paper.

And then we would leave the precipitate on the filter paper to dry, and if necessary, we could further dry it by dabbing it with dry filter paper, or we could place it in a warm oven, and it needs to be warm, not hot.

So let's do a check.

What is required to form an insoluble salt and a precipitation reaction? Which one of these? Well done if you said two soluble salts.

So let's look at another question.

Which pair of solutions would you mix to form barium sulphate, which is an insoluble salt? Quite a lot to think about in this question, isn't there? Which are soluble, which are insoluble, et cetera.

So well done if you said D.

Now, the reason A, for example, barium sulphate is insoluble.

B, both of those are soluble, but you wouldn't make barium sulphate.

There's no sulphate around, is there? And the same is true for part of C.

Let's have a look at task B.

So what I would like you to do for question one here is look at the products we've got there, look at the salt, silver chloride, barium sulphate, iron II hydroxide, and calcium sulphate.

And I want you to think about the reactants that you would use to make those salts.

So pause the video and come back when you are ready.

Okay, let's have a look at how you did.

Your answer might look like this.

So silver nitrate and sodium chloride would make silver chloride.

Barium chloride and sodium sulphate would make barium sulphate.

Iron II chloride and sodium hydroxide would make iron II hydroxide.

Calcium carbonate and sulfuric acid would make calcium sulphate.

So well done.

And if you look at those products, which of those are soluble and which are insoluble? Look at the state symbol to help you.

So you can see that the top three are solids and calcium sulphate is an aqueous solution.

Let's have a look at question two.

I want you to put the following reactants together in separate test tubes and record your observations.

So in test tube one, you're going to put a few drops of silver nitrate and a few drops of sodium chloride.

What do you see happen? And then carry on with the other test tubes.

A clean test tube each time.

And then I'd like you to write the word and symbol equation for each of those reactions.

Pause the video and come back when you're ready.

Okay, how did you do? When you add silver nitrate and sodium chloride, you get a white precipitate, same with barium chloride and sodium sulphate.

Iron II chloride and sodium hydroxide would give you a green precipitate.

Calcium carbonate and sulfuric acid, you get a colourless solution forming.

You would see effervescence or fizzing happening.

And remember, calcium carbonate and sulfuric acid make calcium sulphate, which is soluble, which is why you gain this colourless solution.

And the word and symbol equations next.

There we go.

You might like to pause the video now and check your answers.

Don't forget the correct state symbols.

And remember the last one, calcium carbonate and sulfuric acid, we had a gas being given off because of the fizzing and that's carbon dioxide.

Amazing if you got all those correct.

Well done, well done.

Not easy at all.

Now, let's have a look at the summary, the key things that we need to remember from today's lesson.

So there are a list of general rules which describe the solubility of common types of substances in water.

You need to remember that table.

So go back to the table and just check which compounds are insoluble.

If you remember, it was silver chloride, lead chloride, lead sulphate, barium sulphate, calcium sulphate, most carbonates, and most hydroxides are insoluble.

So pretty much all the others are soluble.

Reactions that form insoluble products are called precipitation reactions, and the solids that are formed are called the precipitate.

When two soluble salts are mixed together, sometimes the atoms rearrange to create an insoluble salt.

We looked at how that would happen and how you would collect the precipitate by filtration and then drying.

Solubility rules can be used to identify which two solutions are needed to mix together in order to create an insoluble salt.

So we've come to the end of the lesson now.

So I hope you feel more confident about what solubility rules are, and that you can name some salts which are soluble, and some salts which are insoluble.

Well done and I look forward to working with you next time.