Let me repost the important information only:
Purpose: The purpose of this experiment is to determine the Ksp for calcium hydroxide.
Materials are:
*50.0 mL of 0.10 M HCl(aq)
*bromophenol blue indicator
*50.0 mLsaturated calcium hydroxide
*50.0 mL buret
*125 mL Erlynmyer Flask
*50.0 mL of distilled water
*10.0 mL pipet with pump
*waste beaker
The procedure for the lab is:
1.Fill the buret with the acid solution.
2.Pipet 10.0 mL of calcium hydroxide into the flask.
3.Add approximately 10.0 mL of water to the flask.
4.Add 4 drops of bromophenol blue to the flask.
5.Titrate the base to an endpoint and record the volume of acid added.
6.Dispose of the flask contents into a waste beaker.
7.Repeat steps 2-6 four more times.
The following is what I am having trouble with.
Present your data in a table.Use the following table as a guide:
Trial 1 Trial 2 Trial 3
*Initial volume
of HCL(mL)
*Final volume
of HCL (mL)
*Volume of
HCL added (mL)
I am having difficulty regarding the trial 1 column. What is my initial volume of HCL(mL) supposed to be?
Regarding the table, trial 1, trial 2 and trial 3 are not so neatly written but they should be shifted a little to the right
I answered this at the original post. If you still have questions, repost here.
Here are my results:
*Initial volume
of HCL(mL)
Trial 1- 0.0
Trial 2- 2.51
Trial 3- 4.95
Trial 4- 7.4
Trial 5- 9.9
*Final volume
of HCL (mL)
Trial 1- 2.51
Trial 2- 4.95
Trial 3- 7.4
Trial 4- 9.9
Trial 5- ?
*Volume of
HCL added (mL)
Trial 1- 2.51
Trial 2- 2.44
Trial 3- 2.45
Trial 4- 2.50
Trial 5- ?
How would I get Final volume of HC (mL) and Volume of HCL added (mL) for trial 5?
You must not have read the final volume for trial 5. Either that or you have misaligned the other readings.
I don't like to intrude but if I may make a comment on this.
I have to say that just like the previous trials didn't you record how much you added for trial 5?
(I'm not understanding how you don't know the volume you added for trial 5)
You CAN however, theoretically calculate about how much HCl you should have added to trial 5)
When I have the table filled out, what would I need to do in order to calculate the solubility product for calcium hydroxide?
The following is what I have in mind, please tell if I am incorrect or correct.
Ksp = [Ca+2][OH-1]2
You should have an average value for the amount of H+ that you put into solution.
For every 2 Mol of HCl added you neutralize one mol of CaOH2 right?
Take the number of mol of hydroxide neutralized and divide by the volume of solution this will give you molarity of the CaOH2.
You know from the stoichiometry that there is 2 times as much OH- present as calcium.
So.. plug these numbers into the equation for the Ksp and you should arrive at your answer.
Ksp = [molarity of OH- / 2 ][molarity of OH-]2
To determine the initial volume of HCl (hydrochloric acid) for Trial 1, you need to follow the procedure mentioned in the experiment. Here's how you can find it:
1. Fill the buret with the acid solution: Fill the buret with the 0.10 M HCl(aq) solution. Make sure to read the initial volume on the buret and record it.
2. Pipet 10.0 mL of calcium hydroxide into the flask: Use a 10.0 mL pipet with a pump to measure and transfer exactly 10.0 mL of the calcium hydroxide solution into the flask.
3. Add approximately 10.0 mL of water to the flask: Add approximately 10.0 mL of distilled water into the flask containing the calcium hydroxide solution.
4. Add 4 drops of bromophenol blue to the flask: Add 4 drops of the bromophenol blue indicator to the flask. This indicator will change color during the titration, helping you determine the endpoint.
5. Titrate the base to an endpoint and record the volume of acid added: Slowly add the HCl solution from the buret to the flask, swirling continuously until the indicator changes color. The color change indicates the endpoint of the titration. Record the final volume of the HCl solution from the buret.
Based on these steps, the initial volume of HCl (mL) for Trial 1 is the same as the recorded initial volume on the buret before beginning the titration. Make sure to carefully read and record the initial volume on the buret before starting the titration process.