||Please keep in mind these things while you do the virtual
titration experiment. (You can view this manual while you proceed
the experiment by using the right side scrolling bar of the Internet browser.)
First, type your name. At every step, you can go back and forth and modify
Step 1, choose either an acid or a base solution that you want to put in
the flask and decide the concentration and volume of the solution.
If you select the "exact" button, the concentration of the solution is
the value in the concentration text box - although the concentration of
this solution in titration is usually unknown. In contrast, if you
select the "random" button, the concentration of the solution, which will
be randomly generated by the program, may not match the value in the concentration
text box. The difference between the value in the text box and the randomly
generated concentration can be up to ±25%.
Step 2, select a standard reagent to fill the burette. If you have
chosen an acid solution for the erlenmeyer flask in step 1, you should
choose a base solution for the buret and vice versa. It is advisable
to use a similar concentration of the solution that you used in step 1,
but a lot more volume than that of the solution in step 1.
Step 3, choose an indicator for titration. The indicator plays an
important role for determining the equivalence point. You want to choose
an appropriate one using the figure showing color vs. pH of several indicators.
If you chose a strong acid and a strong base, the indicator should change
its color near pH 7. For a strong acid and a weak base, the indicator should
change at much less than pH 7. For a weak acid and a strong base, it should
change at much greater than pH 7. For a weak acid and a weak base, it should
change near 7.
Step 4, you now titrate the solutions by moving the scroll bar instead
of opening the cork of the buret to set the drop speed of the solution
from the buret. Monitor the changes of pH value and the color of
solution as well as the change of the volume of the solutions when the
solution is added to the erlenmeyer flask. When you reach the expected
equivalence point, move the scroll bar to the left to reduce the drop speed
of the solution; you may want to add one drop at a time to find the exact
point. When you find an equivalence point, record the volume of the
solution used and add a few more drops to view the more perfect pH curve
of the titration. If you accidentally missed the equivalence point,
you can perform the same experiment again by clicking the button „Restart.š
Step 5, view the titration curve from your data. The titration curve can
be used for determining the equivalence point like an indicator.
The difference between the titration curve and an indicator is that the
titration curve can show how accurately the experiment was performed Ų
The steeper the slope of the titration curve at the equivalence point is,
the more accurate the data are. During or after titration, you can view
the titration curve.
Now let's start the virtual titration lab.
Step 6. enter the volume used in step 4 and you can compare the real value
of the solution and your data. The equation to determine the concentration
of the solution is
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