AS Chemistry Titration

hi!

Can anyone help me with my chemistry titration? I have no idea how to start it off.

I'm using sulphuric acid and solid anyhydrous sodium carbonate.
all they've given us is the concentration of sulphuric acid which is in between
0.05-0.15 mol/dm3

sulphuric acid (aq) + sodium carbonate (aq) --> sodium sulphate (aq) + water (l) + carbon dioxide (g)

I'm supposed to write a plan on what I should do and the amount I should use. But i don'y know where to go from here.

I've calculated 1 mole of sulphuric acid = 98g
1 mole of sodium carbonate = 106g

I also know that I mole of sulphuric acid will react with one mole of sodium carbonate to be neutralised. But I need to know how much sodium carbonate I should use to neutralise the acid.

I don't know where to go from here! Can anyone please help me? I'm really panicking! it's due in very soon! please help! thank you very much!

Reply 1

thefish_uk

Liz88

hi!

Hmmm...

Basically, you need to say you're going to make a 0.1 mol/dm3 solution of sodium carbonate. Meaning 10.6g would be dissolved in a cubic decimetre. But if you're using a 250cm3 volumetric flask, that's a quarter of a decimetre so you'd want 2.65g of solid sodium carbonate. I assume you know the exact technique yourself, you've probably been doing it for the last couple of months like we have.

If you need to know anything else just ask.

Reply 2

DreamGirl_23

Hey!

Thanks a lot for that! I did some calculations this morning and I ended up with the same answer as you! thanks so much!

I hope I do well on my coursework. How much detail should my plan be? I'm using the Salter's course. we're supposed to write a plan about the apparatus, the amount used etc. :redface:

Are there any tips on how to titrate well? How do I know what the rough titre is? cause sometimes, mine ends up lower than everyone elses and i loose marks. does that mean I need to put more sodium carbonate or I just need to make sure that all of the sulphuric acid?

Thanks again to anyone who gives me any help! :wink:

Reply 3

LS.

Ah... I remember this piece of c/w well. We did the exact same piece last year. I got an A on it :biggrin:

The concentration of our acid was 0.15 and I worked it out as 0.1499 (it was the first titration I have ever got such a near perfect answer).

In your aim/planning section include the theory behing the reaction/indicator - justify your indicator/concentrations to be used (and include the amount of anhydrous sodium carbonate you will use inc. equations used to find it).

On your equipment list, include everything you're going to use, and include volumes/concentrations ect.

Include a detailed saftey plan. Don't just copy/paste info on what chemicals you are using; you need to make sure the info relates to the concentrations/amounts you are using.

You actual plan of what you're doing needs to be very detailed - on exactly what you are doing, why you are doing it, and how you will minimise errors (this part of my plan was about 750 words long!), but don't include unessary details.

You will need to initially do a rough titre yourself (time will be allowed for this) - you have no way of knowing what this value should be (as the acid is of an unknown concentration).

On your rough titre get used to your burette, you should be able to use it so when you near your end point you're just getting a small drop coming out the end of it. Remember to swirl the conical flask after every addition of solution. As soon as there is a stable colour change you have hit your end point.

If you need any more help (other than asking on here) use the sheet EL2.1 (I don't the codes changed for this...if so, its the iron-titration sheet).

Good luck :smile:

Reply 4

DreamGirl_23

Thanks for your advice! Did you say I need to talk about the theory behind titration? (I dread doing that) :frown:

Also, the Na2CO3 solution will be in the burette right? And the suphuric acid will be in the conical flask.And I'll be titrating the sodium carbonate solution. Is that right? I'm sort of writing up my plan right now and I'm still a bit confused. :confused:

Please help me.

We haven't been told what universal indicator we'll be using. And the UI will start of being alkali and then acid right?

I'm just using straight forward acid and alkali here right? there's no weak alkali or anything? So i don't need to have two solutions or something?

I'm really panicking, :eek:

because I really want to do well. any help is greatly appreciated.

Reply 5

LS.

I did, but not in much detail, just about the ratio of moles (you'll need that for the con=mol/vol).

I don't think it matters what you put in the burette (I think I read that somewhere) but I put the sodium carbonate in the burette. Have you got the sheet I mentioned in my other post? It is honestly a good resource.

I think you might be a bit confused with the indicators - an indicator is a substance which is one colour in an acid, and another in a base (more complicated that that, I know) - universal indicator is an example of one, methyl orange is another. You should recieve a sheet about the indicators.

You sound like you're a bit confused on strong/weak acids/bases as well- read up on them - you need to know a bit about them so you can decide on what indicator to use.

Don't panic, people here will help you - but no one can really go the work for you. If you are really stuck, it probably would be best to ask a teacher.

For now, I'd use google to look up work on titrations :smile:

Reply 6

DreamGirl_23

ok. thanks again for your advice, in my plan, the sodium carbonate is in the burette and the acid is in the conical flask. :biggrin:

I get the basic theory about indicators. I just always thought they were called 'universal indicators' instead of just plain 'indicators'. Thanks for the clarification, :cool:

I know now that universal indicator is one type of an indicator and so is methyl orange.

Is methyl orange the indicator we're going to use? ( i think i read that somewhere)Will we get told which indicator we use? :smile:

so my solution in the conical flask (acid) will turn from an acidy colour to an alkali?

Also, how do I devise my risk assessment? :confused:

I don't know where to begin. It sounds so simple because to me it's just common sense right? And yet so hard because I don't know how detailed it should be and how much i should write. I'm only using 2 chemicals. That would seem pretty short wouldn't it?

BTW, is the sheet you're refering to the Activity booklet? the green one? :rolleyes:

Once again, thank you very much! i so do appreciate it. I hope everything goes well for me. I'm so sorry if I appear to be so stupid! thanks for being patient.I'll try and ask my teacher! but this is so kind of you and you've helped me a lot!

Reply 7

LS.

I didn't use that indicator, although I think I've seen plans that did use it. As for the colors in solution - google it! It's the way I found out about these things :biggrin:

- because me telling you about these things won't do you any good as you need to mention where you found all the information (be it online or in books) in your referance section (another thing, make sure you note down every site you use with a brief description of what you found, don't leave referancing until the end!)

We recieved information on types of indicators and what acids/alkalis they could be used with. Ask your teacher if you get any information on this.

As for the risk assesment, you need to mention the chemical, hazards and precautions to be taken. Go make friends with the lab tech and borrow the hazcards (or use the online ones).

Two chemicals? Think about your pratical. All of it. Think of every chemical present. It's more than 2!

Activity booklet? Hmm... I wouldn't know. Erm...the sheets are the ones with the abbreviation for the chapter on top - eg SS5.3 (SS being steel story). There is on in the Elements of life on titration. You school should have it. If not, I could scan it in if you're really want it....

Reply 8

DreamGirl_23

I'm thinking about the chemicals I use, I can only really think of two.
sulphuric acid and solid anhydrous sodium carbonate. and maybe the sodium carbonate solution. and indicator? so that's three?

oh dear!

Reply 9

LS.

Look at the reaction formula... :wink:

Remember, with a risk assemsent you need to look at all chemicals which will be present.

Reply 10

DreamGirl_23

ok... I will do.

Hey, is sodium carbonate a strong base or a weak base? I read somewhere that it's apparently a weak base. But then oout teacher gave us info about it being a stong base. And we need to find a suitable indicator for it, by it's equilibrium rate pH thing.