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ed_saifa:
Hey
Question:
Anhydrous sodium carbonate was used in an experiment to determine the concentration of an unknown hydrochloric acid solution. A sample of the carbonate was heated, cooled and weighed until constant weight was obtained.

(a)After being treated as described above, 1.377g of anhydrous sodium carbonate was dissolved in water and made up to 250cm ^3 in a volumetric flask. A 25.00ml portion of this solution was titrated with hydrochloric acid, using methyl orange as indicator. The titration required 22.65mL of the acid for complete neutralization.
(i) Determine the molar concentration of the sodium carbonate solution.
(ii) Determine the molar concentration of the unknown hydrochloric acid solution

(b) A second solution was prepared by dissolving  0.5g of crystalline sodium carbonate in water. This solution was then titrated with another portion of the hydrochloric acid solution. It was found that 30.45mL of the acid was required for complete neutralization.
(i) Calculate the apparent molar mass of the sodium carbonate used in the procedure
(ii) Determine the molecular formula of the crystals used in this procedure

Thank you!

Collin Li:
a)

i.



ii.



Chemical equation:

Toothpaste:


 








Find the moles of in the titration
given: and



Using the equation

ed_saifa:
thanks!

Collin Li:
Toothpick, you're right. I have fixed this consequential error. I realised this when doing part b.

Thanks!

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