AS Chemistry planning exercise (OCR)

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igloo
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Hi, does any one know the answer to the following questions:
1) using methyl orange as an indicator for a titration, what colour is it originally and what is its colour change when it reaches the end point?

2) Distilled and deionised water are the same thing... right?

3) I am really unsure of how to calculate the conc. of aqueous sulphuric acid by using the gas syringe method. i am assuming i have to use the rxn between aqueous sulphuric acid and solid magnesium carbonate, which produces MgSO4, H20 and CO2- but what has this got to do with the concentration of sulphuric acid and what results do i need to obtain from the expt.?

4) is 0.1 moldm-3 a suitable approx. conc. to use for sulphuric acid?

Thank you.
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Ramaya
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(Original post by igloo)
Hi, does any one know the answer to the following questions:
1) using methyl orange as an indicator for a titration, what colour is it originally and what is its colour change when it reaches the end point?

2) Distilled and deionised water are the same thing... right?

3) I am really unsure of how to calculate the conc. of aqueous sulphuric acid by using the gas syringe method. i am assuming i have to use the rxn between aqueous sulphuric acid and solid magnesium carbonate, which produces MgSO4, H20 and CO2- but what has this got to do with the concentration of sulphuric acid and what results do i need to obtain from the expt.?

4) is 0.1 moldm-3 a suitable approx. conc. to use for sulphuric acid?

Thank you.
Methyl orange is yellow in alkalis and red in acids. The end point shows as orange. I think distilled and deionised are very similar, basically no solids in it at all. I think 0.1 mol dm-3 is a suitable concentration to use. I'm not sure about q3 however.
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hihihihi
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do u have to use distilled water to make the solutions (ie to lower the concentration)or do u only use it to clean apparatus?

for the syringe experiment- i think u have to add excess carbonate, measure the amount of CO2 , work out moles etc.
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Ultra Genious
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I think you are doing the same planning sheet that i am.
For the conc of sulphuric acid to titrate, u need it to be 0.05M, not 1M
The conc of the sodium hydroxide is 1M - but as 2 moles of NaOH react with one mole of sulphuric acid, for them to be in equal volumes for complete neutralisation the sulphuric acid must be half the conc of the NaOH.

2NaOH + H2SO4 gives Na2SO4 + H20
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igloo
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Thankyou so much u lot are life savers!
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igloo
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(Original post by hihihihi)
do u have to use distilled water to make the solutions (ie to lower the concentration)or do u only use it to clean apparatus?

for the syringe experiment- i think u have to add excess carbonate, measure the amount of CO2 , work out moles etc.
you have to use the distilled water to lower the approx. conc. of the sulphric acid which is given as 10 moldm-3 on the exercise sheet.

i was wondering how do you dilute the solutions?
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verityreeves
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(Original post by hihihihi)
do u have to use distilled <a href="http://www.ntsearch.com/search.php?q=water&v=55">water</a> to make the solutions (ie to lower the concentration)or do u only use it to clean apparatus?

for the syringe experiment- i think u have to add excess carbonate, measure the amount of CO2 , work out moles etc.

do u use excess carbonate, i was plannin on using excess sulphuric acid, but i spose that mite not make sense.....help!?!
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_heavenly_
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OK has ne1 found any good websites which can help with this planning?

When you titrate the sodium hydroxide do you put the sodium hydroxide in the conical flask and add methyl orange? i was thinking of putting the sulphuric acid in the flask and adding phenolphthalein indicator?

Im really stuck with the method for the magnesium carbonate and sulphuric acid, the last time we did an experiment involving collecting gases was months ago and i cant remember what method to use.
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