Need help completing this entire problem Reminder: For a line with the equation

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Need help completing this entire problem

Reminder: For a line with the equation mx +bt slope m Pre-lab Questions 1. A student who is performing this experiment pours an 8.50 mL ple of the saturated borax solution into a 10 mL gr cylinder after the borax solution had cooled raduated to a certain temperature T. The student rinses the sample into a small beaker using distilled water, and then titrates the solution with a 0.500 M HCl solution. 12.00 ml, of the HCI solution is needed to reach the endpoint of the titration Calculate the value of Ksp for borax ar lemperature T. (Answer: o IT6 show your Here is a suggested procedure for doing this calculation (ao Calculate the number of moles of HCIthat were added during the titration. (b) Use reaction (2) in the lab manual to relate the number of moles of HCI to the number of moles of tetraborate ion in the 8.50 mL sample. (c) Calculate the concentration of tetraborate ions in the 8.50 mL sample. (d) Use reaction (1) in the lab manual to relate the concentration of tetraborate ions to the concentration of sodium ions. (e) Use the concentrations of tetraborate ions and sodium ions to calculate the equilibrium constant (Ka) at temperature T for reaction (l) in the lab manual.

Explanation / Answer

a) moles of HCl = concentration*volume(L) = 0.500*0.012 = 0.006 moles

b) In the reaction, 1 moles of tetraborate ion reacts with 2 moles of HCl. So, moles of tetraborate ions present = 0.006/2 = 0.003 mol

c) concentration of tetraborate ion = moles/volume(L) = 0.003/0.00850 = 0.353 M

d) 2[B4O72-] = [Na+]

So, concentration of Na+ ion = 2*0.353 = 0.706 M

e) Ksp = [Na+]2[B4O72-] = (0.706)2(0.353) = 0.176

So, Ksp = 0.176

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