How do you calculate alkalinity in chemistry?
Ex:
List the values for total alkalinity for Sample A and Sample B
A
104 drops of titrant (5.25mL) 3 drops of C20 H14 O4
B
81 drops of titrant (4.25mL) 3 drops od C20 H14 O4
To calculate alkalinity in chemistry, you will need to perform a titration. Alkalinity is a measure of the ability of water to neutralize acids and is typically determined by titrating the water sample with a standardized acid solution. The steps involved in calculating alkalinity are as follows:
1. Prepare the water sample: Ensure that the water sample is representative and free from any solid particles or impurities that can interfere with the titration.
2. Add the indicator: In alkalinity titrations, a pH indicator called phenolphthalein is commonly used. Add a few drops of phenolphthalein to the water sample. It will turn pinkish when the pH of the solution is around 8.3-8.5.
3. Titrate with acid: Slowly add the standardized acid solution (known as the titrant) to the water sample while stirring continuously. The acid will react with the alkaline components in the water, causing the pink color of the solution to disappear.
4. Observe the endpoint: Continue adding the titrant until the pink color completely disappears, indicating the endpoint of the titration. The endpoint suggests that all the alkaline components in the water have been neutralized.
5. Record the volume of the titrant used: Note the volume of the titrant required to reach the endpoint. Typically, the volume is measured in milliliters (mL).
Now, let's calculate the total alkalinity for Sample A and Sample B using the given titration data:
Sample A:
- Volume of titrant used: 104 drops (equivalent to 5.25 mL)
- Number of drops is not a standard unit of measurement, so let's convert it to milliliters.
- Assuming there are 20 drops per milliliter, divide 104 drops by 20 to get 5.2 mL.
- Therefore, the volume of titrant used for Sample A is 5.2 mL.
Sample B:
- Volume of titrant used: 81 drops (equivalent to 4.25 mL)
- Applying the same conversion calculation, divide 81 drops by 20 to get 4.05 mL.
- Hence, the volume of titrant used for Sample B is 4.05 mL.
By following these steps and considering the given titration data, you can calculate the alkalinity for both samples A and B.