# Titration Analysis By: Adrienne. What is it?? Titration analysis is an experiment used to find the concentration of a substance in a solution. Although.

## Presentation on theme: "Titration Analysis By: Adrienne. What is it?? Titration analysis is an experiment used to find the concentration of a substance in a solution. Although."— Presentation transcript:

What is it?? Titration analysis is an experiment used to find the concentration of a substance in a solution. Although it sounds complex, it is quite simple and relatively easy to perform.

::An Illustration and explanation of a Titration:: First, we fill up the “burette” or “pipetie” at 0 so that we can easily measure how much was used later. As the titration process proceeds, solution from the “pipetie” will slowly drip into the solution in the beaker or “titration dish” Eventually the experiment will reach an endpoint such as the observable colour suddenly changing completely or conductivity. This indicates that a certain amount of the solution in the “pipetie” has reacted with all the solution in the bowl and we have reached the end of the experimental part.

Digging Deeper.. The latter example was a relatively simple experiment that could be performed without much equipment. There are, however, more precise experiments with stopcocks located near the bottom of the burette. These stopcocks control the experiments so carefully that we get much more precise results.

Are we done?? No! We are nowhere near done! This experiment must be repeated several times until 3 trials have volume results within a range of 0.2 mL of each other (the amount of solution used to react with all of the other solution, this is known as the “equivalence point”). Then, these results are averaged out to get how much of the solution was used. This makes the results much more accurate and precise. But wait! There’s still more!!

What Next? Once the experiment part is done, we have to do the calculations. I will show an example experiment lab report that I performed and wrote on the next several slides. This will explain the calculation part of the experiment as well.

I. Purpose The purpose of this experiment is to show one how to perform titration and to decipher between acids and bases. Hopefully the experiment will show how to perform a titration and decipher between acids and bases. Hypothesis: The vinegar will be an acid. The vinegar should be an acid if it turns the solution a pinkish colour. Vinegar seems like it should be an acid because it has a more “sour” taste than “bitter.” The topic is of interest because it shows how to perform a careful titration as well as a quick one and how to figure out the density and concentration of certain substances.

II. Equipment 1. Eyedropper 2. Mass scale 3. Distilled water (available at any grocery store) 4. White sheet of paper (no lines) 5. Stirring rod (or a small spoon) 6. A few leaves of red cabbage (it must be red cabbage, not regular cabbage) 7. 2 beakers (If beakers are not available, one can use a short, fat glass that is transparent, and a small pot to boil water in.) 8. Graduated cylinder (Measuring cups and spoons will work, but the experiment will be much harder.) 9. Clear ammonia solution (This is sold with the cleaning supplies in most supermarkets. It must be clear. A colored solution will mess up the endpoint.) 10. Clear vinegar (Once again, colored vinegar will mess up the endpoint.) 11. Safety goggles

III. Procedure  1. Rinse the beakers, graduated cylinders, and medicine dropper with distilled water thoroughly. If there is any contamination in them, it will mess up the endpoint of the experiment.  2. Take the small beaker (or boiling pot) and rinse it out with distilled water thoroughly.  3. Place the red cabbage leaves in the small beaker and then fill it with about 70 mL (a qualitative measurement) of distilled water. If a boiling pot is being used, three times as much water is probably needed because the water will evaporate faster in a pot than in the small beaker.  4. Boil the cabbage leaves and water in the beaker for approximately three minutes.  5. Let the beaker to cool down, and then carefully take out the leaves from the beaker. The water should be a pinkish-red color. It may be blue-green, but that shows that the water is contaminated a bit. This is the indicator. In the presence of acid (or neutral water) it is a pinkish-red color. In the presence of base, it should be a blue-green color.  6. Take the large beaker and use the graduated cylinder to add 10.0 mL (a quantitative measurement) of the clear ammonia to the beaker. (If measuring spoons are being used, this is 2 teaspoons.)  7. Add 90.0 mL of distilled water (about ½ cup) to the beaker as well. Stir the solution.

III. Procedure Continued…  8. Add a little less than half of the indicator to the beaker. The indicator should turn greenish-blue immediately. This shows the presence of a base, ammonia (NH 3 ). Now a titration will be performed to determine the concentration of the ammonia in the solution.  9. Rinse the graduated cylinder thoroughly with distilled water.  10. Now, measure the mass of the graduated cylinder.  11. Fill the graduated cylinder up with 50.0 mL (a quantitative measurement) of vinegar and measure the new mass of the cylinder plus the vinegar.  12. FInd the mass of the vinegar by difference.  13. Use the mass and the volume (50.0 mL) to calculate the density of vinegar. (If measuring cups are being used, use ¼ of a cup. One must also calibrate the medicine dropper the way it was done in Experiment 5.1, using the ¼ cup as a good approximation of 50.0 mL.)  14. Place the beaker full of ammonia solution on the white piece of paper to make it easy to see the color of the solution.  15. Take the medicine dropper and fill it up from the graduated cylinder full of vinegar.  16. Squirt the vinegar into the ammonia solution and stir. Make sure to watch for any color change. (If measuring cups are being used, One cannot do it this way. Read the following instructions, but only do the instructions in step #27). Keep this until the color of the solution turns pinkish. It will not turn as vividly pinkish-red as the original color of the indicator, but it should turn noticeably pink. This shows that the endpoint of the titration is passed.

III. Procedure Continued…  17. Read the number of mL of vinegar left in the graduated cylinder and, by difference, find how much vinegar that was added in the titration.  18. What was just done is referred to as a “rough titration.” more acid was added than necessary. Start over and do a careful titration.  19. Pour out the titration solution down the drain, and thoroughly rinse the beaker with distilled water.  20. Fill it up again with 10.0 mL of ammonia and 90.0 mL of distilled water.  21. Stir the solution, then add most of what is left of the indicator solution.  22. Put the beaker on the white piece of paper again and then fill the graduated cylinder up again. Make sure the graduated cylinder has precisely 50.0 mL of vinegar in it.  23. Now the careful titration can begin. Use the medicine dropper to quickly add vinegar to the beaker until it gets to within 5 mL of the amount that was added during the rough titration.  24. Now slow down the experiment. Add the vinegar drop by drop and stir thoroughly between each drop. Keep a careful watch on the color. The color should change from green to blue, to a very light blue, and then to a pinkish violet. The pinkish violet color tells you that you have reached the endpoint. The best thing to look for is the very first sign of pink color that exists after the solution has been stirred. As soon as that is spotted, the endpoint has been reached.

III. Procedure Continued…  25. Squirt the remainder of the medicine dropper back into the graduated cylinder.  26.Read the graduated cylinder and, by difference, calculate the number of mL that was added to reach the true endpoint of the titration.  27.If measuring cups are not being used, skip this step. If measuring cups are being used, do a careful titration the first time. Add the vinegar drop by drop, still making sure to keep track of the number of drops that were added. Watch for the endpoint. When it is reached, the number of drops times the dropper calibration will show the number of mL that was needed to add to get to the endpoint.  28.Clean up all the mess.