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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: cindyy on February 21, 2010, 07:29:22 pm

Title: Volumetric analysis
Post by: cindyy on February 21, 2010, 07:29:22 pm

A milky white liquid antacid formulation contains a mixture of magnesium hydroxide and aluminium hydroxide.  A 20 mL sample of the antacid is diluted to 200mL with water.  A 20.0mL sample of the diluted solution is diluted again to 200mL.  A 20.0mL aliquot of this solution required 24.2mL 0.0521M HCl for neutralisation.

a) Write an ionic equation for the neutralisation reaction that occurs.
          Are you supposed to have two equations? :S

b) Calculate the number of moles of OH^- in the aliquot of sample titrate.
          I found the no. of moles of HCl and used the mole ratio, but then i figured since i have 2 equations,  something is wrong ... (Probably part a) so help please :) :)

Title: Re: Volumetric analysis
Post by: fady_22 on February 21, 2010, 07:37:39 pm

a) Equation:
OH-(aq)+ H+(aq)------->H2O(L)

b) n(HCl)=cV=0.0521*0.0242=0.00126 mol
From the equation, n(H+)=n(OH-)=0.00126mol.

Title: Re: Volumetric analysis
Post by: cindyy on February 21, 2010, 07:46:08 pm

ow ... now i feel stupid. hahathank you