Welcome to today's lesson.

Doing more about chemical reactions, this time it's to do with acids and metal carbonates and it's part of the unit acids and bases.

My name is Mrs Mytum-Smithson, and today we're going to learn all about metal carbonates and their reactions with acids.

Don't worry if you don't know much about these because we're going to go through the lesson step by step and by the end of the lesson you should be able to describe what happens when a metal carbonate reacts with an acid and write chemical equations to describe these reactions.

Today's keywords are chemical test, limewater, acid rain, chemical weathering.

There's some sentences that include these keywords on the next slide, so if you wish to read them, pause the next slide and then press play when you're ready to start the lesson.

Today's lesson consists of three learning cycles.

First, we're going to learn all about metal carbonates.

Then we're going to move on and learn the chemical test for carbon dioxide.

And finally, we're going to look at acid rain.

So let's get going with our first learning cycle of metal carbonates.

Metal carbonates are salts that consist of a metal and a carbonate group.

For example, zinc carbonates.

So you can see here it's just a white powder and a carbonate group consists of one carbon atom and three oxygen atoms bonded together.

The chemical formula for zinc carbonate is ZnCO3.

So you can see there we've got the metal, which is zinc, and we've got the carbonate group, which is one carbon atom joined to three oxygen atoms. So that makes up the carbonate group.

Quick check for understanding now which compounds have the correct chemical formula for carbonates? So take a look at those.

Is it CaCO3, MgCO2, K2CO3, CaSO4? So there might be one or more answers that are correct here, and I want you to select those.

So pause the video whilst you do so and then press play and we'll go through the answer or answers together.

Well done if you said calcium carbonate is a carbonate and also potassium carbonate is a carbonate.

You can see the correct formula for a carbonate is one carbon atom joined to three oxygen atoms. So well done if you got that correct.

Calcium carbonate, CaCO3, is the main compound in chalk and marble.

So here's some chalk cliffs in Dover, very famous cliffs, you might have heard the song about them.

We've also got a marble statue, so marble can be carved into statues.

So you can see here this is a marble statue and that's made of calcium carbonate.

And also here's a wall made of limestone.

When metal carbonates react with acids, they produce a metal salt, water and carbon dioxide.

Here you can see the reaction between calcium carbonate and sulfuric acid.

The carbon dioxide gas can be seen as bubbles or effervescence in the reaction mixture.

So you can see here the white calcium carbonate powder is added and the bubbles start to be produced.

We call that effervescence.

When metal carbonates react with acids, a metal salt, water and carbon dioxide are produced.

So we can write this as a general equation.

Metal carbonate plus acid makes metal salt plus water plus carbon dioxide, and you can see the metal salt gets its name from the metal carbonate and the acid gives the ending of the metal salt.

The type of metal carbonate and acid used determines which metal salt is made.

So let's have a look.

We've got these three acids that we are familiar with.

Hydrochloric acid, sulfuric acid, and nitric acid.

So if you use hydrochloric acid, the ending of the metal salt name is going to be chloride.

If you use sulfuric acid, you're going to get sulphates.

If you use nitric acid, you're going to get nitrates.

Let's have a look at an example of this.

So here we've got copper carbonate plus nitric acid makes copper nitrate plus water plus carbon dioxide.

So you can see here we've made copper nitrate.

The copper from that comes from the copper carbonate and the nitrate is from the nitric acid used.

So if we want to make copper nitrate, we must use a copper carbonate and nitric acid.

I'm going to show you another example of this now.

So we've got zinc carbonate plus hydrochloric acid, makes zinc chloride plus water plus carbon dioxide.

So here you can see the metal salt.

It's a zinc salt because we've used zinc carbonate and it's a chloride.

So the ending of the metal salt name, chloride, comes from the hydrochloric acid.

What I want you to do is use the information in the table to help you name the salt produced in the reactions.

So here's two reactions, lead carbonate plus sulfuric acid.

I want you to name the metal salt and you get plus water plus carbon dioxide.

And the same we've got iron carbonate plus nitric acid.

What metal salt does that make? Plus water plus carbon dioxide.

So you're going to pause the video whilst you do this and then press play and we'll go through the answers together.

So well done if you said lead carbonate plus sulfuric acid makes lead sulphate plus water plus carbon dioxide.

So iron carbonate plus nitric acid makes iron nitrate plus water plus carbon dioxide.

So well, if you got both of those metal salt names correct.

Quick check for understanding now what is the gas produced when a metal carbonate reacts with an acid? Is it water, is it hydrogen, is it oxygen or is it carbon dioxide? So pause the video whilst you decide, then press play and I'll tell you if you're right or not.

Well done if you said that the gas produced was carbon dioxide.

Now what I want you to do is select the products produced when potassium carbonate and sulfuric acid react together.

What do they make? So is it potassium sulfuric, water and carbon dioxide, potassium sulphate, water and carbon dioxide, sodium sulphate, water and carbon dioxide, potassium sulphate, carbon dioxide and hydrogen.

Pause the video while you select your answer and then press play and I'll let you know if you're right or not.

So well done if you said that potassium carbonate and sulfuric acid react together to make potassium sulphate, water and carbon dioxide.

Well done if you got that one correct.

Symbol equations including state symbols can be written for the reactions of carbonates and acid.

So what we're going to do now is we're going to write the word equation.

So we've got zinc carbonate plus hydrochloric acid, makes zinc chloride plus water plus carbon dioxide.

Then we're going to add in those state symbols.

So zinc carbonates are solid.

So that gets a little S in subscript in brackets.

And then we've got hydrochloric acid.

So that's a solution.

So that's AQ in subscript, in brackets in lowercase, and then that's going to make zinc chloride, which is soluble.

So that's going to be aqueous AQ, lowercase in brackets in subscript, and we've got water.

Water is a liquid at room temperature, so that's liquid.

And then we make the carbon dioxide.

The carbon dioxide is a gas at room temperature, so we're going to put a lowercase G in brackets and put that in subscript.

Next we're going to have a look at the symbol equation for this.

So all we've got to do is where there's words, we are going to replace those with symbols.

So we've got zinc carbonate, that's ZnCO3.

Remember, a carbonate is one carbon atom bonded to three oxygen atoms. And then we've got hydrochloric acid symbol for that is HCl, and that's going to make zinc chloride plus water plus carbon dioxide.

So we're then going to just put the state symbols in, so they're just the same state symbols as the ones above it.

So zinc carbonate's a solid.

Hydrochloric acid is a solution, so that's AQ.

Then zinc chloride is soluble in water, so that's AQ and there's some water, so that's liquid.

And carbon dioxide is a gas.

We've already looked at zinc carbonate reacting with hydrochloric acid.

Now we're going to have a look at it reacting with two other acids to see what kind of metal salt we get.

So here's our first one.

We're going to look at nitric acid and zinc carbonate.

So zinc carbonate plus nitric acid is going to make zinc nitrate.

That's the metal salt plus water plus carbon dioxide because we always get water and carbon dioxide produced when a carbonate reacts with an acid.

So here we've got the symbol equation.

So we've got zinc carbonate plus nitric acid that's going to make zinc nitrate plus water plus carbon dioxide.

So you can see now that the zinc nitrate, the zinc part of it is from the carbonate that we used.

And the second part of that metal salt, the nitrate part comes from the fact that we've used nitric acid.

So if we have a look at another example, we've got zinc carbonate plus sulfuric acid, and this time we're going to make zinc sulphate plus water plus carbon dioxide because we always make water and carbon dioxide with our metal salt.

So we've got a carbonate here, we've got zinc carbonate, and then that reacting with sulfuric acid.

And we're going to make a zinc salt this time because you can see.

So we make a zinc salt, but this time instead of a nitrate, we've used sulfuric acid.

So we're going to make a sulphate and we've always got plus water plus carbon dioxide.

I've got a quick check for understanding here.

When magnesium carbonate, that's MgCl3 and hydrochloric acid, that's HCl, react together, carbon dioxide, water and a metal salt are formed.

What is the chemical formula for the metal salt formed? Is it MgCl2, ZnCl2, or MgSO4? Pause the video whilst you decide, then press play and I'll tell you the answer.

Well done if you said that the formula was MgCl2, because we've used magnesium carbonate, the first part of the metal salt name always comes from the carbonate and the second part comes from the acid used.

So well done if you got that correct.

What I want you to do now for task A is complete the reactants or products for the following word equations that show the reaction between different carbonates and acids.

Use the information in the table to help you.

So we've got some information there.

So we've got the name of the acid, the name of the metal salt ending.

So what I want you to do is complete either the reactants or the products, whatever's missing.

So A, the reactants are tin carbonate plus sulfuric acid makes, and you are going to tell me what the products are.

And then for B, we've got the reactants missing this time.

So you are going to tell me what reactants would you need to make lead sulphate plus water plus carbon dioxide.

Then for C, we've got lead carbonate plus nitric acid, and you're going to tell me what the products are that are made.

So pause the video whilst you do that, please write the word equations.

So you just need the words, no symbols please.

And then once you've done that task, press play and we'll go through the answers together.

So well done for completing that task.

Firstly, we did tin carbonate plus sulfuric acid.

We reacted those together.

And you should have written tin sulphate because we've got a tin carbonate.

So that's the tin part of the metal salt.

And then the sulfuric acid makes sulphates.

So tin sulphate plus water plus carbon dioxide because we always get water, carbon dioxide and a metal salt when you're reacting carbonates with an acid.

Now we're moving on to B.

What did we need to have to make lead sulphate, water and carbon dioxide? So we must have had a carbonate and that must have been a lead carbonate.

And because we made sulphates, we must have had a acid that was sulfuric acid.

So lead carbonate plus sulfuric acid makes lead sulphate plus water plus carbon dioxide.

For C, what we are going to do here is we just need the products made between lead carbonate and nitric acid.

So you're going to make a lead salt here and this time instead of it being a lead sulphate, 'cause we've used a different acid, we've used nitric acid, we're actually going to make lead nitrate and then plus water plus carbon dioxide.

So well done if you've got all of those three correct, you're doing really well.

What I want you to do now for part two of task A is use the information in the table to help you complete the equations when potassium carbonate reacts with different acids, I want you to include the state symbols for reactants and products.

The equations are already balanced for you.

You can see from the formula of potassium carbonate that it is a solid.

Pause the video whilst you complete the task and then press play when you're ready for the answers.

Well done for completing that task.

Hope you got on okay with it.

Let's have a look at the answers then.

So A, so we've got K2CO3, that's potassium carbonate reacting with hydrochloric acid and that's going to produce potassium chloride.

Now we're going to have a look at the state symbols for these.

So let's put these in.

So potassium carbonate is a solid, so we'd write a little S in brackets, lowercase and subscript.

Hydrochloric acid in the lab is always a solution, so that's AQ.

And then the product there.

So potassium chloride is soluble in water, so that would form a solution AQ, in brackets.

Water is always a liquid at room temperature, so that's a little lowercase L in brackets subscript and carbon dioxide is a gas at room temperature.

So that would be a lowercase G in brackets.

Now we're going to have a look at B.

So here we've got potassium carbonate reacting with nitric acid and this time we're going to make potassium nitrate.

So let's put the state symbols in for that.

So here we've got solid again for potassium carbonate, aqueous solution for the nitric acid.

And then because a soluble salt is made, the potassium nitrate is AQ 'cause it dissolves in the water that's made.

The water is a liquid at room temperature, so that's going to be an L in brackets.

And carbon dioxide is always a gas at room temperature.

So that's going to be a lowercase G in brackets in subscript.

Now let's take a look at C.

So C, we're going to have potassium carbonate reacting with sulfuric acid and we're going to make potassium sulphate plus water plus carbon dioxide.

Let's have a look at the state symbols for that.

So again, potassium carbonate is a solid reacting with sulfuric acid, which is in solution.

So that's AQ.

And then we're going to make a soluble salt.

So potassium sulphate is soluble in water, so that would be AQ in brackets.

And then we've got the water, which is a liquid at room temperature and the carbon dioxide, which is a gas at room temperature.

So well done if you've got all of those correct.

We've completed our first learning cycle.

Now we're going to take a look at the chemical test for carbon dioxide.

When carbonates and acids react together, they produce bubbles of carbon dioxide gas.

And you can see this because they fizz or they bubble or effervesce and you can see that happening here.

So here's some hydrochloric acid, here's some copper carbonate.

And you can see here's some carbon dioxide gas being created in bubbles.

Now carbon dioxide gas is an odourless, so it has no smell, it's colourless, which means you can't see it, which means that you need some way of identifying it.

So in order to confirm that the gas produced is carbon dioxide, we can carry out a chemical test and that's going to prove, give us some evidence to show that that is carbon dioxide gas being produced, and not a different gas being produced.

The chemical test for carbon dioxide gas is to bubble gas through limewater.

So here's our equipment that we're going to use.

So we've got hydrochloric acid, we've got a bung, now that's got a hole in it for the delivery tube and that bung stops all the gas from just going into the air in the classroom.

We've got a delivery tube and the gas will travel along the delivery tube to where we want it to be in that test tube.

So you can see we've got the calcium carbonate reacting.

The gas is produced, it travels along that delivery tube and it bubbles through the limewater that we've got in in the test tube.

And that limewater will turn from a colourless solution to a cloudy or milky-white solution.

So you should be able to see through it at the start 'cause lime water is colourless and then it will start to become cloudy and milky.

And that means that you've got carbon dioxide gas there.

So the carbon dioxide will turn the colourless solution to a cloudy, milky-white solution.

Now if the gas is not carbon dioxide, then the solution will remain colourless.

So you might have a reaction where you're producing some gas.

You carry out this test and it turns out that it's not carbon dioxide and you would know this because it would not turn cloudy.

So it will only turn cloudy if there's carbon dioxide gas being produced.

A quick check for understanding now.

What would the limewater look like after carbon dioxide gas has been bubbled through it? Would it be red, would it be green, or would it be cloudy white? Pause the video whilst you decide, then press play and I'll tell you the answer.

Well done if you said cloudy white.

The chemical test for carbon dioxide is that after gas has been bubbled through it, the limewater would turn cloudy white.

So well done if you got that correct.

I've got a true or false for you now.

If you bubble any gas through limewater, it will always turn cloudy, milky white.

Is that true or is that false? Pause the video for some thinking time and press play when you've got your answer.

So well done if you said that is false.

So I want a justification for that now.

So you've got two choices.

If the gas is hydrogen, it will turn cloudy or milky white.

If the gas is carbon dioxide, it will turn cloudy or milky white.

So pause video while you have a little think, then press play and I'll tell you the answer.

So well done if you said B, if the gas is carbon dioxide, it will turn cloudy or milky white.

If not, then the limewater will stay colourless.

So it will only turn milky white or cloudy if the gas is carbon dioxide.

'cause that is a chemical test for carbon dioxide.

So well done if you got that one correct.

When carbonates and acid react, the carbonate will reduce in size and will eventually not be visible when it has all reacted.

So here's our example.

So we've got copper carbonate.

We've got at the start of the reaction, during the reaction and after the reaction.

So when the metal salt's produced, it's soluble and so it will dissolve and make a metal salt solution.

So you can see here we've got copper carbonate at the start of our reaction.

During the reaction you can see that the size is starting to reduce and after the reaction can see that it's not visible anymore because it's all reacted.

So there's our copper chloride solution and the metal salt solution produced, it might be coloured in this case or colourless, and that depends on the metal salt produced.

I've got a check for understanding for you.

On this slide, there's the information.

And on the next slide there's the question.

Acid-based cleaning products should never be used on a marble surface.

The students placed a piece of marble into a test tube containing hydrochloric acid.

The students observed that bubbles formed and the marble got smaller.

So here's the experiment that they carried out.

They placed marble into some hydrochloric acid.

They saw that bubbles formed and after a while they saw that that marble got smaller.

What I want you to do now is explain what happened in the test tube.

The marble dissolved in the acid.

The acid ate away the marble, a chemical reaction formed a new soluble substance.

The marble changed into the gas state.

So pause the video while you decide which one you're going to select and then press play and I'll tell you the answer.

Well done if you said a chemical reaction formed a new soluble substance, well done if you got that one right.

For part one of task B, it's a practical task.

What I want you to do is carry out an experiment as shown below, adding calcium carbonate to hydrochloric acid and test for carbon dioxide gas.

I want you to write down your observation.

So I want you to write down what you see, hear, feel.

So we've got a calcium carbonate there.

Going to put that into the conical flask with some hydrochloric acid.

You're going to place the bung with the delivery tube in it, and you're going to place that in a test tube with some limewater.

Please note down the limewater colour at the start, it's colourless.

I want you to make sure that you observe what happens to that.

So pause the video while you carry out this practical, then press play and we'll have a look about what you saw.

So you might have observed the following, effervescing or fizzing or bubbling of calcium carbonate.

The calcium carbonate reduces in size or gets used up, so that's going to get smaller or not be visible at all.

And the limewater should change from colourless to milky or cloudy white because that's the test for carbon dioxide and carbon dioxide gas is produced.

So well done if you've managed to get some of those observations down.

Here's part two for task B.

Izzy has been doing an experiment to test the gas produced by three different reaction mixtures.

She knows that carbon dioxide gas is produced from reaction A and C, but not from reaction mixture B.

Complete her results table to describe what she should expect to see.

So here's a results table.

The left hand column, you've got the reaction mixture and then you've got two observations.

The first observation is the limewater colour before bubbling gas through it.

And the second one is the limewater colour after bubbling gas through it.

So pause the video while you complete her results table and then press play and we'll go through the answers together.

So well done for completing that task.

Let's have a look at what you should see.

So she said she knows that carbon dioxide gas is produced from reaction A and C.

So let's have a look at reaction A.

So the limewater colour before bubbling gas through it is colourless.

And afterwards you should have said that it turns cloudy or milky white.

Now, reaction mixture B, it says that carbon dioxide gas is not produced.

So the limewater is colourless before bubbling the gas through it.

And it should also be colourless after bubbling the gas through it because that gas is a different gas and it's not carbon dioxide so it wouldn't have the same reaction.

And then C, she knows that C produces carbon dioxide.

So the limewater colour before bubbling gas through it is colourless and then it changes to cloudy or milky white once that carbon dioxide gas is bubbled through it.

So well done if you got those answers correct.

Here's part three of task B now.

What I want you to do is describe the gas test for carbon dioxide.

I want you to include details for a positive test where carbon dioxide is present and a negative test where the gas produced is not carbon dioxide.

So pause the video whilst you complete this task and then press play and we'll go through the answer together.

Well done for completing part Three of task B.

Let's see how you got on.

So your description should match mine pretty closely.

So the first thing you're going to do is you're going to describe the gas test.

So the gas should be bubbled through limewater and the colour of the limewater observed.

Then you're going to tell me a positive test.

So if the limewater changes from colourless to milky or cloudy, then the gas is carbon dioxide.

Then you're going to tell me the negative test.

So if the limewater stays colourless, the gas is not carbon dioxide, so well done for completing that task.

We've completed our first two learning cycles.

Now we're going to learn about acid rain.

Now rainwater is usually slightly acidic and when it's more acidic than normal, it's called acid rain.

So acid rain has got a pH of 5.

6 or less, if not then it is rain.

Now acid rain and rainwater will both react with carbonates causing chemical weathering, but this reaction is slow and takes place over many years.

Chemical weathering can be seen in nature and on older buildings and statues.

So here we have a gargoyle that has been weathered by acid rain.

So remember acid rain has got that pH that's less or equal to 5.

6.

So although rainwater will cause chemical weathering, acid rain will cause that chemical weathering to take place faster.

Marble and limestone are made of calcium carbonate and acid rain reacts with the calcium carbonate to produce a salt, water and carbon dioxide and some of the calcium carbonate in the marble is used up in that reaction and that's why it gets weathered.

So here's a picture of some weathered limestone.

You can see here the rocks are worn away by the acid rain.

What I'd like you to do now is choose the word to complete the sentence.

Rainwater is usually slightly, is it slightly acidic, slightly neutral or slightly alkaline? Pause the video, select your answer, and then press play and I'll tell you if you're right.

So well done if you said rainwater is usually slightly acidic.

True or false, the effective acid rain can be seen on marble or limestone buildings and statues within a week? Is that true or is that false? Pause the video whilst you decide, then press play and I'll tell you the answer.

Well done if you said that that statement was false.

Now on to justification.

So you've got acid rain has a very low pH of one to two, so weathering takes place over many months or acid rain has a pH of just less than 5.

6 so weathering takes place over many years.

Pause the video while you have a think, and press play when you've got your answer.

Well done if you said acid rain has a pH of just less than 5.

6 so weathering takes place over many years.

So well done if you got that correct.

I've got part one of task C now.

Lucas has been on holiday and he wants to know what happened to the stone that has disappeared from the statues in the photographs.

He said that the tour guide told him the statues are made of limestone but had more defined features many years ago when they were first made.

What I want you to do is explain to Lucas what has happened to the statues.

So pause the video whilst you do that, then press play and we'll go through your answer together.

Well done for completing this task.

So your answer, so you might have included some of this information in your answers.

Limestone is made of calcium carbonate.

Calcium carbonate reacts with acids to form metal salts, water and carbon dioxide.

Metal salts formed are soluble in water, so will dissolve in the rain and over time the calcium carbonate in the statue will react with the acid rain and get used up in the reaction, so will undergo chemical weathering.

Here's part two of task C.

Laura has planned an experiment to see if a piece of marble she has found is affected by acid rain and will become weathered.

So here's Laura's experimental plan.

She's going to collect some rainwater.

She's going to fill a beaker with the rainwater, place the marble in the rainwater, leave for a week, observe the marble to see if it's reduced in size and look for bubbles forming.

Do you think Laura's experiment will work? What I want you to do now is I want you to evaluate Laura's experiment.

So I want you to tell me if you think it'll work and why it will work or why it won't work.

So you need a conclusion for this 'cause it's an evaluation.

So pause the video whilst you do this and then press play and we'll go through your answer.

Well done for completing that task.

Your answers might include, Laura's experiment would not work or give her results.

So you should have said that no, Laura's experiment's just simply not going to work and give her the results that she wants.

So the rain might not be acidic enough to be acid rain 'cause she's just collecting the rain from outside, which might not be pH 5.

6 or lower.

There's not enough time to see the effect of acid rain.

So you need years of acid rain rather than just a week that she suggested.

And there's not enough acid rain.

So there's only one beaker used compared to much more rain in the weathering process.

So those statues and buildings and rocks, they're rained on with lots and lots and lots of rain rather than just one beaker of rain.

And the reaction's happening very slowly.

So because it's happening so slowly, it's unlikely that you'd be able to see bubbles or even a change in the size of a piece of marble, given that she's only gonna do this for a week.

So well done if you've managed to get some of those points correct.

Here's a summary for today's lesson.

A group of one carbon atom and three oxygen atoms bonded together is called a carbonate group and it's written CO3.

Metal carbonate plus acid makes metal salt plus water plus carbon dioxide.

The chemical test for carbon dioxide gas is to bubble it through limewater as it turns the solution cloudy or milky.

Rain water is usually slightly acidic and when it is equal to or less than pH 5.

6, it is called acid rain.

Acid rain reacts faster than rainwater with marble to produce a salt, water and carbon dioxide using up some of the marble.

Well done for completing this lesson, I'm sure you've worked really hard.

I hope you're now more confident knowing about the definition for acid rain, how to test for carbon dioxide, and how metal carbonates react with acids.

I hope to see you sometime soon.