Students are given a solution of K2CO3, but its concentration is unknown. Two students take different approaches to determine its concentration: Student X took 20.00mls of the K2CO3 solution and added 20.00 mls of 0.2000 M HCl in a conical flask and left the solution stirring for half an hour. The solution in the conical flask was then titrated with 0.1500 M NaOH. Repeating this procedure gave an average titre of 20.05 mls. Student Y took 20.00mls of the K2CO3 solution into a conical flask and titrated it directly against 0.2000 M HCl. Repeating this procedure gave an average titre of 3.55 mls. (i) Write the appropriate equations for the reactions above. (ii) Determine the concentration of the K2CO3 solution from the data obtained by Student X and by Student Y. Express your answers as M and g/L. (iii) Both methods give different values for the final concentration. Explain the difference, highlighting the more accurate method.
Students are given a solution of K2CO3, but its concentration is unknown.
Two students take different approaches to determine its concentration:
Student X took 20.00mls of the K2CO3 solution and added 20.00 mls of
0.2000 M HCl in a conical flask and left the solution stirring for half an hour.
The solution in the conical flask was then titrated with 0.1500 M NaOH.
Repeating this procedure gave an average titre of 20.05 mls.
Student Y took 20.00mls of the K2CO3 solution into a conical flask and titrated
it directly against 0.2000 M HCl. Repeating this procedure gave an average
titre of 3.55 mls.
(i) Write the appropriate equations for the reactions above.
(ii) Determine the concentration of the K2CO3 solution from the data obtained
by Student X and by Student Y. Express your answers as M and g/L.
(iii) Both methods give different values for the final concentration. Explain the
difference, highlighting the more accurate method.
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