Measuring Ph

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MEASURING pH

Date of Lab: 02/09/13
Date Report submitted: 02/26/13

Purpose of the experiment
By doing this experiment, we were trying to learn how to measure a pH with a pH meter to determine whether a solution is weakly, moderately or strongly acidic or basic; but also to compare the different data founded to see how the addition of certain liquid to a solution may affect the pH of the initial solution.

Materials
We used:
* Tap water, distilled water, Soda and milk as the main liquids to be mixed and measured in terms of pH * One Rolaid antacid tablet and Lemon juice to mix with distilled water in order to create a Dissolved Rolaid solution and a dilute lemon juice * A graduated cylinder to measure the different liquids

* 4 100 ml beakers to store the liquids
* A hammer to crush the Rolaid antacid tablet
* A tissue to crush the Rolaid antacid tablet in
* Pr mixer
* 2 pH meters to measure the pH of the different liquids and solutions

Method

* First, we read the instructions to see where to start.
* Second, we measured 50 mL of tap water and stored it in the 1st beaker, then we did the same thing with the soda and the milk and stored it in the 2nd and 3rd beakers. * While one member of the group was measuring the pH of the tap water, another one was measuring the pH of the soda then the one of the milk and we recorded the data. * After that, we measured 40 ml of distilled water, stored it in the 4th beaker, measured its pH and recorded the data. * Then, we added 10ml of lemon juice to the distilled water in the 4th beaker in order to create a dilute (1:5) lemon juice; we mixed it with //, measured the pH of the solution and recorded it. * Once done with recording the initial pH of the tap water, soda, milk, distilled water and dilute lemon juice, we poured the tap water, which was in the 1st beaker, in the sink and cleaned the beaker * Then, we measured 50ml of distilled water and stored it in the 1st beaker * Following the process, with a hammer we crushed one Rolaid antacid tablet in between a tissue and added the powder to the 50ml of distilled water. We mixed it with … in order to obtain a dissolved Rolaid solution and with the pH meter, we measured its pH and recorded it. * After that, we measured 10 ml of dissolved Rolaid solution and added it to the 50ml of soda in the 2nd beaker. We mixed it, obtained a Rolaids-Soda solution, measured its pH and recorded. * Then, we added again 10ml of the Dissolved Rolaid solution to the obtained Rolaids-Soda solution, measured its pH and recorded (we repeated this step one more time). * Once done with measuring the pH of the Rolaids- Soda solution with first 10ml, 20ml and then 30ml of dissolved Rolaids solution in the soda, we measured in a graduated cylinder 10 ml of the dilute lemon juice that we added to the 50 ml of milk in the 3rd beaker; we mixed it, measured its pH and recorded it. * Then, we added again 10ml of the dilute lemon juice to the obtained lemon juice-milk solution, measured its pH and recorded (we repeated this step one more time).

Results

Liquid| Initial pH| Rolaids-Soda Solution | | Lemon Juice-milk Solution| | 1. Tap Water| 6.6| mL of Rolaids Solution| pH| mL of Dilute Lemon Juice solution| pH| 2. Distilled Water| 5.5| 0| 3| 0| 6.1|

3. Soda| 3| 10| 4.6| 10| 4.3|
4. Milk| 6.1| 20| 4.8| 20| 5|
5. Dilute(1:5) lemon juice| 2.3| 30| 5.3| 30| 4.2|
6. Dissolved Rolaid solution| 6.1| | | | |

1. Tap water with a pH of 6.6 is a weakly acidic solution somewhat neutral. 2. Distilled Water with a pH of 5.5 is a strongly acidic solution 3. Soda with a pH of 3 is also a strongly acidic solution 4. Milk with a pH of 6.1 is slightly acidic

5. Dilute lemon juice is strongly acidic
6. Dissolved Rolaid solution, as the milk seems to be slightly acidic.

All the measured liquids have a pH below 7, which means...
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