Molarities of Solutions: Solution Molarity NaOH 0.1015 M HCl...

Molarities of Solutions: Solution Molarity NaOH 0.1015 M HCl 0.1006 M HC2H3O2 0.1018 M Titration of Hydrochloric Acid: mL base needed to reach the equivalence point: 24.4 mL Show how you determined this volume from your titration curve. Turn in your computer generated plot of pH vs. Volume from DataStudio along with your data. For each point shown below in the titration, record your measured pH from your data, and then calculate the pH of the solution. Show your work for all calculations in the space provided. 1) What was the pH of the hydrochloric acid before any base was added? Measured pH = 1.5 Calculated pH = 1.00 Calculations: -log [HCl] -log [.1006] = .997 -> 1.00 2) What was the pH after 10.0 mL of sodium hydroxide solution were added? Measured pH = 1.7 Calculated pH = 1.38 Calculations: HCl: 24.4 mL * .1006 M = 2.45 mmol NaOH: 10.0 mL * .1015 M = 1.015 mmol 2.45 - 1.015 = 1.44 mmol 1.44 mmol / (24.4 + 10 mL) = .04185 M = [H+] -log[H+] = 1.378 -> 1.38

Transcript

00:02 So, in the table, the solution molarity are shown.

00:07 Sodium hydroxide 0 .1015 molar, hydrochloric acid 0 .1006 molar, and acetic acid 0 .1018 molar.

00:18 So, the question asks you the titration of the hydrochloric acid.

00:23 The milliliter base needed to reach the equilibrium point is 24 .4 milliliter.

00:30 So, first of all, for the question, number one, you have two different values.

00:38 One is the measured ph directly from the ph meter.

00:41 And also, you will have a calculated ph number, which is going to be from the calculated molarity of the hydrochloric acid.

00:52 So, according to the measurement, the measured ph is 1 .5.

01:08 So, what about calculated? so, we know that before the neutralization of sodium hydroxide, we have the molar of hydrochloric acid 0 .1006 molar or mole per liter.

01:34 Now, hydrochloric acid dissociate to form hydrogen ion and chloride ion.

01:42 So, one mole of hydrochloric acid produce one mole of hydrogen ion and also one mole of chloride.

01:59 Now, since we have 0 .1006 molar of hydrochloric acid, we can deduce that the concentration of the molar concentration of hydrogen ion or proton is also 0 .1006 molar.

02:21 Now, to calculate the ph, we have to use this formula, negative log concentration of proton.

02:41 And then we just plug that in.

02:42 And the unit of this molarity of proton is actually molar.

02:48 So, you get 0 .997.

02:55 And again, according to the question, you can round it up to about 1.

02:59 But you can also leave it as 0 .997.

03:02 So, this actually calculate the first question.

03:10 The second question says, what was the ph after 10 milliliter of sodium hydroxide solution was added? very first step, you want to calculate a total mole of sodium hydroxide.

03:25 So, this is going to be calculated by the volume times the concentration.

03:35 In this case, the volume is going to be 10 milliliter.

03:41 And the concentration of the sodium hydroxide is 0 .1015 mole per liter, which is also molar, same unit.

03:57 So, let's calculate the total mole of sodium hydroxide.

04:02 We also know that 1 mil equals 0 .001 liter.

04:10 So, 10 mil is going to be 10 times 0 .001.

04:16 You get 0 .01 liter.

04:19 Then you times 0 .1015 mole per liter.

04:25 You get 0 .001015.

04:32 So, this is the amount of sodium hydroxide has been added already.

04:38 But according to the first part of the question, titration of hydrochloric acid, milliliter base needed to reach the equilibrium point is 24 .4 milliliter.

04:47 So, this means that the total sodium hydroxide needed mole, this is to titrate hydrochloric acid is going to be 24 .4 milliliter times, again, concentration 0 .1015 mole per liter.

05:27 Again, 0 .0244 liter times 0 .1015 mole per liter.

05:40 You get 0 .002477 mole...

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