[AppState11]

I'm having trouble with the moles of OH- for my lab report. My lab instructor made it seem like the moles of HCl & OH- will be the same, but then asks for the calculation of each of them as if they are different. I'm not sure what information is needed so I will just post what I have and my lab report requirements. Any other help you can give me with the report would be greatly appreciated as well

Molarity of HCl: 0.1836


                                                    Trial 1                      Trial 2
Vol of saturated solution titrated           50.5                          49.75
Initial buret reading                             7.11                          1.59
Final buret reading                              30.1                           24.45
Vol HCl added                                     22.99                         22.86
Moles HCl added                                 4.221 moles                4.197 moles
Moles OH-                                                                      
Molarity of OH-                                                                
Numerical value for x                                                         
K_sp of compound                                                              
Average K_sp                                                          


That's the info that I have or still need & here are the lab requirements... Like I said, I don't know about the moles of OH- so I got stuck after the first one listed here:


3. The calculation to obtain the moles of HCl added for trial 1.
          ----> molarity x volume = moles HCl
          ----> 0.1836 x 22.99mL = 4.221 moles

4. The calculation to obtain the moles of OH- present in trial 1.

5. The calculation to determine the concentration (in molarity) of OH- (aq) in the solution that was titrated for trial 1.

6. The calculation to obtain the value of x for trial 1.

7. The calculation to determine the K_sp of your unknown hydroxide compound for trial 1.

8. What is your experimentally determined value for the molar solubility of your alkaline earth hydroxide for trial 1.

9. Show the calculation to obtain the average K_sp from your experimental trials.

10.   Answer the following questions. Show all work!

1. Determine the correct chemical formulas for the following:
a)   carbon disulfide      b)   lithium nitrate      c)  tin(II) iodide


2. Determine the correct chemical names of the following species:
a)  Sr(OH)2         b)  NaHCO3          c)  KClO3

3. The following data were collected from a K_sp experiment on an alkaline earth hydroxide. Calculate the K_sp of the alkaline earth hydroxide.

volume of saturated solution titrated   27.5  mL
molarity of HCl   0.176 M
volume HCl required for endpoint   13.17 mL
 

4. An alkaline earth hydroxide, M(OH)2, was taken to lab for analysis. The unknown powder was poured into a flask and swirled in room temperature DI water until a saturated solution formed. This solution was then slowly filtered to remove the undissolved solid hydroxide.  35.9  mL of this saturated solution was titrated with 0.143 M HCl (aq). Endpoint required 17.72 mL of the HCl (aq) solution. Calculate the K_sp for this alkaline earth hydroxide.



Again, Thank you so much to anyone that can provide any help whatsoever!