Hello, my name's Mrs. Nevin, and today we're going to be talking about concentration of solutions using moles as part of our unit on making salts.

Now, you may have some experience of what we do in today's lesson from your previous learning, but what we do today will help us to not only answer those big questions of what are substances made of, how can they be made, and then how can they be changed, but we'll also be able to better appreciate the simple solutions that we come across in everyday life.

So by the end of today's lesson, you should hopefully feel more confident being able to explain what we mean when we talk about the concentration of a solution, as well as be able to calculate it for various solutions.

Now, the keywords that we'll be using throughout the lesson as well as their definitions are provided on the next slide.

You may wish to pause the video here so you can jot them down for reference later on in the lesson or later on in your learning.

Today's lesson is broken into three parts.

We'll start by looking more closely at describing what we mean when we talk about concentration before moving on to look more closely at the units that are used for concentration and finish up the lesson by calculating concentration.

So let's get started by describing what we mean when we use the term concentration.

Many chemicals that chemists come across and use are found in their aqueous form and these are indicated to us.

Using that state symbol of aq, which you may recall simply means that a substance has been dissolved in water and exists as a solution.

So we have an example here of sodium chloride that has dissolved in water.

Then we have copper sulphate and many of the other chemicals that we commonly use in the science lab are also found in that aqueous form as a solution.

Things like acids, here we have sulfuric acid and our alkalides here, sodium hydroxide, and we can tell that all of these are solutions simply by looking at their labels because they have that aq state symbol.

Now a solution is composed of a solute that's dissolved in a solvent.

Now the solvent in aqueous solution is simply water H2O.

So the solute is our solid here, the solvent is our liquid that it's dissolving into, and the resultant mixture then is a solution.

Let's stop here for a quick check.

Which of the following statements is true about an aqueous solution of sugar? Well done if you said a and d.

Because it's an aqueous solution, we know that water is the solvent and we'd be able to show that it's a solution using that state symbol of aq.

So very well done if you've got at least one of those correct and extremely good start to this lesson if you managed to both of those correct answers.

Fab work guys, keep it up.

Now the thing about using the term concentration is that it actually has been used to explain a few different things in everyday life.

For instance, you might describe somebody focusing on their work as concentrating or having good concentration on that work.

The word concentration has even been used to describe Worlds War II camps, and it might even be used to describe drinks as a concentrated drink.

But in chemistry specifically, concentration is used to describe a solution in terms of its solute and its solvent.

Concentration is simply a ratio of solute particles to the volume of solvent that those particles are dissolved in.

Now you may recall that volume represents the amount of space that a substance occupies.

So if we wanted to find the volume of this cube, we'd simply multiply its length times its width times its height, and we could say that the volume of this particular space is 1,000 centimetres cubed or one decimeter cubed.

So if I had two solutions of the same volume, concentration can help to indicate how crowded those solute particles are when they're dissolved in that solvent.

For instance, if I had one decimeter cube of solvent and I only had a few particles of solute dissolved in it, I could describe the concentration of that solution as being low.

Few particles of solute, quite a low concentration.

If I had more particles dissolved in the same volume of solvent, so many particles, I would describe that concentration as being high or higher than the other one.

So many particles dissolved in a solvent gives us a high concentration and we can see that without having to zoom in to those solutions because higher concentration solutions tend to appear quite dark.

Now I can control or adjust the concentration of a solution by changing the amount of solute that is dissolved in a specific volume of solvent.

So if I add a large amount of solute into a specific volume of my solvent, I'm putting many solute particles dissolving in that volume and I get a higher concentration.

If I want a lower concentration, I'm going to add a smaller amount of solute providing fewer solute particles and that would then result in that lower concentration.

Another way that I might be able to adjust the concentration of a solution is by adding distilled water to that aqueous solution.

Because what that does, is it increases the volume of the solvent, so increases the space in which those solute particles are dissolved in.

Now what that actually is doing is diluting that original solution.

So a diluted solution has a lower concentration than the original solution.

So if my original solution has a high concentration of solute particles dissolved in a specific volume of solvent and I add some water to it, I end up with a larger total volume of solution.

But those solute particles are now spread out within that larger volume creating a lower concentration.

Now it's really important if you are diluting a solution that you use distilled water because what that does is ensure that there are no other substances present in that solution.

You still have the same solvent in with the same solute particles.

Let's take a moment for another quick check.

True or false? Solution X has a lower concentration than solution Y, and I'd like you to explain your answer.

So justify your choice on whether or not that statement is true or false.

Well done if you chose false.

Now, there were a few different ways that you could justify that answer.

You could have said that solution X is darker in colours suggesting that it contains more solute particles and therefore a higher concentration, or you could have referred to solution Y saying that that is lighter in colour, suggesting that it contains fewer solute particles and therefore a lower concentration.

So very well done if you managed to choose the correct answer of it being a false statement, but incredibly well done if you were able to justify your choice with your explanation.

Great job guys, well done.

Okay, time for the first task in today's lesson.

What I'd like you to do is use words from the box to complete the passages below.

So pause the video and come back when you're ready to check your answers.

Okay, let's see how you got on.

<v ->Now, if you completed the passages correctly,</v> it should read out like this.

If a substance dissolves in water, it is said to be soluble.

The substance that dissolves is known as the solute and the water is the solvent.

The resulting mixture is known as a solution.

Chemists often carry out reactions in solution.

As such, the concentration of each solution used should be stated.

This informs others about how much substance has dissolved in a certain volume of solvent.

Well done if you manage to get that correct.

If you use the incorrect word at any point.

Please do make sure that you have corrected that as we went through this so that you have a complete summary of what we mean by concentration.

Well done though if you managed to get those correct guys.

Great job.

For this next part, I'd like you to use your understanding of concentration to help Jacob.

He's been asked to create a sweet cordial drink for grandmother, but she thinks it tastes a little too sweet.

So what could Jacob do to change the concentration of his grandmother's drink so that it tastes less sweet? And I'd like you to explain how your suggestion would help him.

So pause the video here and come back when you're ready to check your answers.

Okay, let's see how you got on.

Now, the best way to do this would be to simply add some water to his grandmother's drink because that would dilute the drink, making it less concentrated and that would help to make that drink taste less sweet.

We really don't want to be creating a whole new drink by pouring out what he's already made and then simply putting in less of that cordial to create that drink, which you could have done because that's just wasteful.

So if you did say start over, use less of the cordial drink and add some more water, then that would still be a correct answer, but the better answer would be to use the drink you started with and simply add some water to it.

Well done though if you managed to suggest to add water and very well done if you were able to explain how that would fix his grandmother's drink.

Very well done guys.

Great start to this lesson.

Now that we're feeling more comfortable being able to describe what we mean when we use that term concentration, let's look more closely at the units that are used to describe concentration.

When we're provided with the value for the concentration of a solution, what that value is actually representing is a ratio between the solutions number of solute particles to the volume of solvent that's been used.

Now, the volume of a solution or the amount of space that that solution occupies is equal to the volume of the solutions solvent and that tends to be measured out using a measuring cylinder.

Now, different situations may call for different volumes.

For instance, if you are going to be using a solution for an investigation in the laboratory versus using a solution for an industrial process.

Now because of that, it's important to understand that volume can be quoted in a variety of units.

So I have an example here, a 1,000 millilitres is equal to 1,000 centimetres cubed.

Now that's the same volume as one decimeter cubed or one litre.

Now these smaller volume units of millilitres and centimetres cubed tend to be used for investigations in the laboratory, whereas those larger units of decimeter cubed and litres may be used for an industrial process.

Now, if you are doing an investigation in the laboratory using those units of centimetres cubed but want to upscale it for an industrial process, you would then need to be able to convert between your investigation unit of centimetres cubed to your industrial unit of decimeters cubed.

And to do that, you would simply divide your value by a 1,000.

Similarly, if you had an idea for an industrial process but wanted to investigate it in the laboratory first, you might take that decimeter cubed value and have to multiply by a 1,000 to convert it to centimetres cubed to use in the an investigation in the laboratory.

Now, a measuring cylinder measures volume in centimetres cubed, but the standard unit for concentration quotes volume in decimeters cubed.

So we'd need to be able to convert between our centimetres cubed and decimeters cubed when doing any of those calculations in the laboratory.

Now you could do that easily by dividing by a 1,000, or we can use a simple rhyme to help us do the same thing.

c to the d, one, two, three.

Let's look at an example.

I have 500.

0 centimetres cubed.

I changed my c to a d simply by adding that line, and then I'm going to move the decimal point three places to the left, one, two, three.

Following that rhyme then, 500 centimetres cubed is equal to not 0.

500 decimeters cubed simply by changing the c to a d and then moving that decimal place three places to the left.

Let's stop here for a quick check.

What is the volume in decimeter cubed of 15.

2 centimetres cubed.

Well done if you said c.

Now you could have done it in two ways.

You could have either divided that volume by a 1,000 or you could have used our rhyme c to the d, one, two, three, and you'd have got the same answer of 0.

0152 decimeters cubed.

So well done on getting that first one right guys, fab work.

The number of solute particles that have dissolved in that volume of solvent then is measured in moles.

Now, you may recall that one mole is equal to 6.

02 times 10 to the 23 particles.

Now, we can't measure out a mole of solute particles because one, it's too difficult we can't actually individually pick up one particle at a time, and secondly, it would take far too long to count that number of particles.

So instead we use that mathematical relationship of mass in grammes is equal to the relative mass of the substance times the number of moles that are being used.

And we use that then to calculate the mass that we can then measure out on a balance of the solute that we would like to dissolve in our solvent.

So let's have a go at reminding ourselves how to use that mathematical relationship.

I'd like to know what the mass is of 0.

015 moles of zinc carbonate to two significant figures.

So the first thing I need to do is find the value of the relative mass for my substance of zinc carbonate, and I do that by adding up the mass of each atom in that substance and I get a relative mass of 125.

If I multiply that by then the number of moles that was given to me in my question, I get a value of 1.

875, but to two significant figures then, that mass should be 1.

9 grammes.

What I'd like you to do now then is to calculate the mass of 0.

0075 moles of potassium permanganate to two significant figures.

Make sure you're showing all your working out and you may wish to discuss your ideas and strategies with the people around you.

But pause the video now and come back when you're ready to check your answer.

Okay, let's see how you got on.

So you should have got a final answer of 1.

2 grammes if you've calculated this out correctly.

If you haven't, please do pause the video here and go back through your workings out so we can identify where you've gone wrong so you can avoid that error in the future.

But very well done if you manage to get the correct answer.

Guys, great job.

So once you know the mass of solute required for a particular concentration, you can measure that out then using a balance.

Now, a solute mass can be measured in different units, just like the volume could be measured in different units or quoted in different units.

But for concentration, the standard unit for the mass of solute is in grammes, but like volume, you can convert between different units, milligrammes for instance or kilogrammes and between them all the way along.

And what you'll notice as you move from the smaller unit on the left of milligrammes, up to the larger units of kilogrammes on the right, we are dividing by a 1,000.

And as we move from kilogrammes, that large unit down to milligrammes, we're going to be multiplying by a 1,000.

Which means then 1,000 milligrammes is equal to one gramme, which is also equal to 0.

001 kilogrammes.

Now because a solution is made up of particles of solute that's been dissolved in a volume of solvent, the concentration of that solution needs to be quoted in terms of the units for both of those components.

So standard units for concentration could be quoted in either grammes per decimeter cubed or moles per decimeter cubed.

Now these can also be written as g/dm to the minus three or moles/dm to the minus three.

Let's stop here for another quick check.

Which of the following could be units for concentration? Well done if you chose a, c and d.

Now, c is the standard unit for concentration, but a and d both show a ratio of the number of particles per a unit of volume and therefore could also be considered a unit for concentration.

So very well done if you at least got c and spectacular work if you also managed to choose a and, or d as well.

Great job guys.

Let's move on to the second task in today's lesson.

What I'd like you to do here is to please place each word or phrase into the appropriate column based on how you might group these ideas as either being related to a solute, related to the solvent or related to the solution.

So pause the video and come back when you're ready to check your answers.

Okay, let's see how you got on.

For the solute I would've put quite a few of those options in there.

So we're talking about the number of particles, grammes, mass, milligrammes, kilogrammes, balance and moles.

So we're looking at the units, what those units represent and how I would measure out some of that solute itself.

For the solvent then I would've put centimetres cubed, water, decimeters cubed and measuring cylinder and for solution then, moles per centimetre cubed, mixture and grammes per decimeter cubed.

Very well done if you managed to get those correctly matched up guys, great job.

For the last few questions in this task then, I'd like you to do a few conversion calculations and to give your answers to two significant figures.

So as always, please do show you're working out so that we can identify any errors if they do crop up when we go through the answers later and pause the video and come back when you're ready to check your answers.

Let's see how you got on then.

2a, you should have an answer of 0.

046 decimeters cubed, and b then should be 250 centimetres cubed.

3a then should be 3,500 grammes, and b then should be 0.

0068 grammes.

For question four, you needed to use that mathematical relationship of mass is equal to the relative mass times moles, and for a, you should have had an answer of 76 grammes and for b, you should have an answer of 170 grammes.

Remember, all of these answers are to two significant figures.

So very, very well done for this task guys.

Great work and keep it up.

So we now know what we mean when we talk about concentration and the units that are used to describe it.

Let's move on to discuss how we can calculate the concentration of various solutions.

We need to remember that concentration is simply a ratio of the number of particles of solute that have dissolved in a particular volume of solvent.

What that means then is that equal volumes of solutions that have the same concentration will have the same number then of dissolved solute particles.

And to double check that we could calculate the concentration of that solution using two different equations.

The concentration is equal to moles divided by volume or concentration is equal to the mass of our solute divided by the volume it's dissolved in.

And we can actually convert between these two equations or mathematical relationships using that other mathematical relationship that the mass in grammes of our solute is equal to the relative mass of each individual particle times moles or the number of particles that have actually dissolved.

Let's stop here for a quick check.

Which two of these samples have the same number of dissolved solute particles? You may wish to pause the video so you can discuss your ideas with those around you and then come back when you're ready to check your answers.

Well done if you chose a and d.

Both of these solution samples have the same number of dissolved solute particles because they have the same concentration and the same volumes when you convert those units and make them equivalent.

So very, very well done if you chose that pairing guys, great job.

Let's look at how I can use that mathematical relationship using concentration.

I'd like to know what the concentration is in grammes per decimeter cubed of a solution that is composed of 15 grammes of sodium chloride that has dissolved in 0.

35 decimeter cubed of water and I want to know that concentration to two significant figures.

So I know I'm going to need to use this relationship of concentration is equal to mass divided by volume, and I know that one, because I've been given the units in grammes per decimeter cubed.

And also when I look at the other values for my solute in solvent, I can see that I've been given those values in grammes and decimeters cubed.

Now because of that, all I need to do is pop those values into the correct position within my mathematical relationships.

So 15 divided by not 0.

35 gives me a concentration of 42.

86, but to two significant figures then, my final answer should be 43 grammes per decimeter cubed.

What I'd like you to do now then is to please calculate the concentration in grammes per decimeter cubed of a solution that's composed of 5.

2 grammes of sugar dissolved in 1.

6 decimeters cubed of water.

And again, to give your answer to two significant figures.

So please pause the video here while you'll do your working out and then come back when you're ready to check your answer.

Okay, let's see how you got on.

If you've carried out your calculations correctly then to two significant figures, you should have a final answer of 3.

3 grammes per decimeter cube.

If you didn't manage to get that, please do pause the video here so you can check through your working out and identify any errors that we could try to avoid going forward, but very well done if you managed to get that correct.

Great job guys.

Let's take a look at another example.

This time I'd like to know the concentration in moles per decimeters cubed of a solution of 0.

50 grammes copper sulphate that's dissolved in 0.

25 decimeters cubed of water and to give that answer to two significant figures.

So I'm going to have to use the relationship of concentration is equal to moles divided by volume because the concentration has been quoted in moles per decimeters cubed.

I wanna take a closer look at the other values that have been provided in the question.

I have my solute in grammes and my volume in decimeter cubed.

So I'm going to need to convert the grammes into moles.

And I do that by finding first of all the relative mass of the substance that has dissolved, that copper sulphate.

And I find then by adding up the masses of all the atoms in one particle of copper sulphate gives me a relative mass of 159.

5.

If I then find the number of moles then by dividing the mass by the relative mass, I get a moles of 0.

003135.

So I now have moles and I have the volume of solvent that was used.

So I simply put those two numbers into my mathematical relationship and I get a concentration of 0.

01254.

However, I've been asked to quote this concentration to two significant figures.

So my final answer should be 0.

013 moles per decimeter cubed.

What I'd like you to do now then is to find the concentration in moles per decimeter cubed of a solution that contains 0.

25 grammes of silver nitrate that is dissolved in 0.

15 decimeters cubed of water, and please give your answer to two significant figures.

So pause the video here while you do your working out and then come back when you're ready to check your answer.

Okay, let's see how you got on.

If you've done your calculations correctly, you will have had to do another mole calculation, so converting your mass into moles and that gives you a final answer to two significant figures of 0.

0098 moles per decimeter cubed.

So again, if you didn't get that answer, please do pause the video so you can compare your working out to that that's shown and we can identify any errors to try and fix as we go forward.

But very, very well done if you manage to get that correct guys, fantastic work.

Now, like all mathematical relationships, our equation for concentration can be rearranged in order to calculate an unknown volume of solvent or the mass of solute to be used.

So we could take this equation of concentration equals mass divided by volume and rearrange it so that the volume of solvent we may need is equal to the mass that's being dissolved divided by the concentration, and that the mass of the solute that's used would be equal to the concentration times the volume.

Now the thing to remember here is that the values for our solute and, or our solvent may need to be converted into those appropriate units before we calculate the solutions' concentration.

So remember that the solvent, so the volume then, needs to be in cubic decimeter or dm cubed, and the solute then must be in moles or grammes and you'll decide which one that is based on the concentration units.

When you're being asked to calculate an unknown value, it's usually helpful to employ a strategy.

So my suggestion would always be to make sure the first thing you do is choose the appropriate equation for what you're being asked to calculate.

Is it concentration, the particles, so that's the moles of the mass or the volume of the solvent when we're talking about concentration.

The next thing you need to do is identify the values you have available in your question and ensure that they're all in the correct units that you need for your equation that you're using and that may need some converting.

So remember, the number of particles of your solute will be in moles of grammes, the volume should be in decimeter cubed, and then the concentration then will be either in moles per decimeter cubed or grammes per decimeter cubed.

And then finally once you have those values in the correct units for the equation you need to use, you can simply put those values in that equation and solve for your unknown.

Let's have a go at using that strategy then.

I want to know what mass of solute must dissolve in 250 centimetres cubed of water to produce a solution that has a concentration of 2.

3 grammes per decimeter cubed.

And I want my answer to two significant figures.

The first thing I notice is I've been asked to calculate a mass of solute.

That means I need to use that mathematical relationship of mass is equal to concentration times volume.

The next thing I'm going to do is to go back and circle any of the values and their units within the question.

And the reason I do that is I can then easily compare the units to see if anything needs converting.

And I notice here that the volume's been provided in centimetres cubed, but I need it in decimeters cubed.

So by converting that, by dividing by a 1,000 or using my rhyme c to the d, one, two, three, I have a new volume of 0.

250 decimeters cubed.

I now have a concentration in a volume that I can stick into my relationship.

So 2.

3 times 0.

250 gives me a mass of 0.

575, but to two significant figures, that final answer then is 0.

58 grammes.

Okay, what I'd like you to do now then is to calculate what volume was used to dissolve 0.

0102 moles of potassium sulphate to create a solution with a concentration of 1.

10 grammes per decimeters cubed, and to give your answer to two significant figures.

Please pause the video here, show all of your working out, perhaps check your answers as you go along with the people nearest you, and then come back when you're ready to check your work.

Let's see how you got on.

Now, if you've done your calculations correctly, you should have a final answer of 1.

6 decimeters cubed.

Crucially, you will have needed to convert moles of potassium sulphate into grammes so that your units for the solute matches.

So it is a tricky thing here, but managed to get that correctly.

Very, very well done to you.

Great job here guys, fantastic work.

Time to move on to the last task in today's lesson.

What I'd like you to do is to help on Andeep.

He's preparing to make some solutions of sodium sulphate.

So what I'd like you to do is calculate what massive solute he needs to dissolve in order to produce these solutions, and please give your answers to two significant figures.

So pause the video here and come back when you're ready to check your answers.

Let's see how you got on.

So for part a, you needed to use that relationship of mass is equal to concentration times volume, and we compare the units that we've been provided of the values, we notice that the volume needs to be converted to decimeters cubed.

Once that has happened and you put the values into your relationship, you get a final answer to two significant figures of 13 grammes.

For b, then we notice that the concentration has been given to us in moles per decimeters cubed.

So we need to be using that first relationship of moles as equal to concentration times volume.

So once we've done that, you have the number of moles of sodium sulphate that is dissolved.

You then need to use the relationship of mass is equal to relative mass times moles to calculate the mass in grammes, which is 2.

1 grammes to two significant figures of the sodium sulphate that has been used.

So very well done if you manage to get that correct.

For this next question, let's start applying our understanding of concentration to more familiar solutions.

A mug of instant coffee contains 70 milligrammes of caffeine dissolved in 50 centimetres cubed of hot water.

What is the concentration of caffeine in milligrammes per centimetres cubed and moles per decimeter cubed.

And please give your answers to two significant figures.

So pause the video here and come back when you're ready to check your work.

Let's see how you got on.

We've been asked to find the concentration, so we're going to be using that relationship of concentration is equal to mass divided by volume.

Now we've been asked to find the concentration in milligrammes per centimetres cubed, which is exactly the units we've been given for our solute and our solvent.

So simply dividing those values gives us our answer to 1.

4 milligrammes per centimetres cubed to two significant figures.

2b was a little bit more complicated because I now need to calculate that concentration in moles per decimeters cubed.

So I'm going to use the relationship of concentration is equal to moles divided by volume.

But when I take a closer look at the values that were provided in the question, I don't have anything in moles, so I'm probably also going to need to use that relationship of moles as equal to mass divided by relative mass.

Now, when I take a closer look at those units for my solute in solvent, they both need converting to standard units.

So volume divided by a 1,000 will give me a new volume of 0.

050 decimeter cubed, and the mass from milligrammes to grammes, again divided by a 1,000, gives me a new mass of 0.

070 grammes.

The next thing I need to do is convert the mass to moles.

So finding the relative mass of caffeine using the chemical formula that was provided gives you the number of moles of 0.

0003608.

And thou am able to calculate the concentration.

So putting those correct values into my relationship for concentration gives me a final answer to two significant figures of 0.

0072 moles per decimeters cubed.

Incredibly well done if you manage to get that correct.

But definitely make sure that you are giving yourself some marks if you are doing these conversions correctly for the units because those are particularly difficult.

Another common solution you might find relates to children's medicines.

Now, some children's medicine contains paracetamol which is a painkiller, and the concentration of paracetamol in those medicines is 24 grammes per decimeter cubed.

And a single dose of that medicine should contain 120 milligrammes of paracetamol.

So the first thing I'd like you to do is to calculate what volume of medicine in centimetres cubed will contain the required mass of paracetamol for a single dose.

And for the next thing I'd like you to do then is to calculate how many moles then of paracetamol are in a single dose, and to give that answer to three significant figures.

Pause the video here, show your working out, compare your ideas, strategies, and answers with the people around you and come back when you're ready to check your work.

Okay, let's see how we got on.

So I know that I need to calculate the volume of medicine.

So I'm using the relationship volume is equal to mass divided by concentration.

And when I take a closer look at the values that have been provided, I noticed that the mass has been given to me in milligrammes, so I need to convert that to grammes as the standard unit by dividing by a 1,000.

I then use the new values and my concentration value into my relationship and I get an answer of 0.

005 decimeters cubed.

However I've been instructed to give that final answer is centimetres cubed.

So I need to convert my volume in decimeter to the correct units, and I do that by multiplying by a 1,000.

That gives us a final answer of five centimetres cubed is a single dose that would contain 120 milligrammes of paracetamol.

So very well done if you manage to get that correct.

Great job guys.

Okay, for question b, I was asked to calculate the number of moles of paracetamol in a single dose.

So I need to use that relationship of moles is equal to mass divided by the relative mass of the substance.

Now, from my previous answer, I had already calculated the milligrammes into grammes, which is the standard unit, so that is 0.

120 grammes, but I need to now find the relative mass for the paracetamol.

So using that chemical formula, I get an answer of 151.

Taking those two values then and putting them into my moles relationship, I find an answer to three significant figures of 0.

000795 moles of paracetamol is found in a single dose of children's medicine.

Very, very well done if you manage to get that correct.

Great job guys.

Wow, we have gone through a lot in today's lesson.

So let's take a moment to just summarise what we've done.

Well, we've learned that an aqueous solution is essentially the mass of solute particles that have been dissolved in a particular volume of solvent.

Now, that's usually about one decimeter cubed of distilled water, and that would mean then the concentration for that solution could be given in grammes per decimeter cubed.

Now, the mass of one mole of solute is equal then to the relative mass of the solute that's measured in grammes, meaning that the concentration for a solution could be expressed in two ways, either grammes per decimeters cubed, or we could express it in moles per decimeters cubed.

We've also learned that equal volumes of solutions of the same concentration have equal numbers of dissolved solute particles.

And finally, we've spent a lot of time looking at the fact that volume and mask can be expressed in a variety of units, and because of that, we can easily convert from one unit into a standard unit in order to express and compare different concentrations.

So incredibly well done today guys.

I've had a great time learning with you.

I hope you've had a good time learning with me, and I hope to see you again soon.

Bye for now.