CH223_Ch_12_Gravimetry

Molarity of Na2S2O3 (stock solution).    0.100 M Volume of diluted bleach titrated (taken from the volumetric flask).  10ml Initial Burette Reading.  14.80 Final Burette Reading     25.60 Volume of Na2S2O3 used in the titration (mL).    10.80 Moles of Na2S2O3 used in the titration.   1.71 Moles of S2O3–2 used.     1.66 Moles of I2 initially present in titration mixture 0.83 Moles of NaOCl in the diluted bleach titrated.   0.415 Volume of bleach titrated. 1ml Mass of commercial bleaching solution titrated ?

Molarity of Na2S2O3 (stock solution).    0.100 M Volume of diluted bleach titrated (taken from the volumetric flask).  10ml Initial Burette Reading.  14.80 Final Burette Reading     25.60 Volume of Na2S2O3 used in the titration (mL).    10.80 Moles of Na2S2O3 used in the titration.   1.71 Moles of S2O3–2 used.     1.66 Moles of I2 initially present in titration mixture 0.83 Moles of NaOCl in the diluted bleach titrated.   0.415 Volume of bleach titrated. 1ml Mass of NaOCl in commercial bleach titrated.  ?

Molarity of Na2S2O3 (stock solution).    0.100 M Volume of diluted bleach titrated (taken from the volumetric flask).  10ml Initial Burette Reading.  14.80 Final Burette Reading     25.60 Volume of Na2S2O3 used in the titration (mL).    10.80 Moles of Na2S2O3 used in the titration.   1.71 Moles of S2O3–2 used.     1.66 Moles of I2 initially present in titration mixture 0.83 Moles of NaOCl in the diluted bleach titrated.   0.415 Moles of OCl– in the diluted bleach titrated.   ?

Complete the Titrimetric Data table.

Aspirin powder = 0.8110g MW of Aspirin = 180g.mol-1 Volume of 0.5N HCl consumed in back titration = 23.50mL Volume of 0.5N HCl consumed in blank titration = 44.50mL Percent purity (USP/NF) = Aspirin tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of aspirin (C9H8O4) What is the calculated weight (in grams) of pure aspirin?..

Find out the molarity of an old KOH solutionYou measure 1.456 g of KHP (MW=204.22 g/mole) dissolve it in 50.0 of H20 add an indicator and begin to titrate with the old KOH KHP (aq) +KOH (aq) =K2P (aq) +H2O (l) the initial and volume burette readings are 1.35 mL & 24.3 mL then what is the concentration of KOH ?

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Part A) A 10.0 mL sample of 0.250 mol/L NiF2(aq) is mixed with 20.0 mL of 0.0900 mol/L NaOH(aq) and then diluted to a final volume of 100. mL.Calculate the concentration of Ni2+ ions in the 100 mL mixture before the reaction starts. Express your answer to three significant figures.ksp: 5.48e-16

2A student used a pipette to add 25 cm³ of sodium hydroxide of unknown concentration to a conical flask. The student carried out a titration to find out the volume of 0.1 mol/dm3 sulfuric acid needed to neutralise the sodium hydroxide. The following is the table of results obtained. Titration Volume of sulfuric acid used/cm³ 1 27.85 27.30 27.25 27.10 27.30 a. Write down a balanced equation for the reaction between sodium hydroxide and sulfuric acid. b. Describe the titration experimental procedure (details of washings are expected) c. Determine the average titre value and explain your choice of titre values in calculating the average. d. Determine the concentration of sodium hydroxide. e. If instead of sulfuric acid, hydrochloric acid of the same concentration was used what would you expect the average titre value to be and why?

TOPIC: GRAVIMETRY SHOW THE SOLUTION The mercury in a 0.7152-g sample was precipitated with an excess of paraperiodic acid, H5IO6, according to the following reactions:5 Hg+2 + 2 H5IO6 ---> Hg5(IO6)2(s) + 10 H+The precipitate was filtered, washed free of precipitating agent, dried and found to weigh 0.3408-g. Calculate the percentage of Hg2Cl2 in the sample. Molar Masses: Hg5(IO6)2 = 1448.75 Hg2Cl2 = 472.09 Answer: 38.82% Hg2Cl2   An iron ore was analyzed by dissolving a 1.1324-g sample in concentrated HCl. The resulting solution was diluted with water, and the iron (III) was precipitated as the hydrous oxide Fe2O3·xH20 by the addition of NH3. After filtration and washing, the residue was ignited at a high temperature to give 0.5394 g of pure Fe2O3. Calculate (a) % Fe, and (b) % Fe3O4 in the sampleMolar Masses: Fe2O3 = 159.69 Fe = 55.847 Fe3O4 = 231.54  Answer: 33.32% Fe and 46.04% Fe3O4

Trial 1 Trial 2 Trial 3 Initial burette reading (mL) 2.29   1.41   1.95   Molarity of NaOH (M) 0.100   0.100   0.100   Volume of vinegar sample (mL) 5.00   5.00   5.00   Final burette reading (mL) 50.37   49.39   49.84 Table 2. Titration data   Trial 1 Trial 2 Trial 3 Initial burette reading (mL) 2.29   1.41   1.95   Molarity of NaOH (M) 0.100   0.100   0.100   Volume of vinegar sample (mL) 5.00   5.00   5.00   Final burette reading (mL) 50.37   49.39   49.84   Expected color at end point       Volume of NaOH used (mL) 48.08   47.98   47.89  Compute for the ff: a.   Average moles of acetic acid (mol)? b.  Average molarity of acetic acid (M)? c.  Average molarity of acetic acid (M)?

Provide full complete solution do not round off numbers and show proper labelling and cancellations

For the CO2 impact experiment station: 1)         Obtain two plastic cups, red cabbage indicator, a straw, and plastic wrap. 2)         Fill each cup approximately one-quarter to one-third full of tap water and add ~10 mL of the red cabbage indicator. 3)         Place the two cups side by side on a sheet of white paper. 4)         Place the straw into one of the beakers and cover that beaker with the plastic wrap. 5)         Carefully blow bubbles into the test cup for 3 min. and observe both cups.  6)         Compare the color to the control cup and record any differences. This the Question:  Did the beaker with the solution into which CO2 was bubbled change pH/color?  By how much?  Is this what, you would predict, based on your knowledge of the chemistry of CO2?

B. Molar Concentration of an Acid Solution Acid type, HA or H,A: HA Unknown No. Balanced equation for neutralization of acid with NaOH. NaOH + HCI = NaCI + Sample 1 Sample 2 Sample 3 1. Volume of acid solution (mL) 25.0 25.0 25.0 2. Buret reading of NaOH, initial (mL) 0.00 0.00 0.00 3. Buret reading of NaOH, final (mL) 26.3 26.0 26.8 26.3 26.0 0.148 4. Volume of NaOH dispensed (mL) 26.8 5. Molar concentration of NAOH (mol/L), Part A 6. Moles of NaOH dispensed (mol) 7. Molar concentration of acid solution (mol/L) 8. Average molar concentration of acid solution (mol/L) Data Analysis, B 9. Standard deviation of molar concentration Data Analysis, C 10. Relative standard deviation of molar concentration (%RSD) Data Analysis, D

Volume vinegar used (mL)= 5.00 mL % from labe= l5 % Molarity of NaOH = 0.0976 M Titration volume measurements   Trial 1 Trial 2 Trial 3 Inital volume NaOH (mL) 0.69   0.86   0.16   Final volume NaOH (mL) 43.47   43.36   43.03   Volume NaOH used (mL)             Average volume NaOH used (mL) Average volume NaOH used (L) Moles NaOH used (from avg volume) Moles CH3COOH Molarity CH3COOH (mol/L) Mass CH3COOH (g) % (m/v) CH3COOH in vinegar

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1.10 M Acetic acid 0.900 M Sodium acetate [H30*1 (M) Solution (mL) |(mL) 1 8.00 2.00 8.71e-5M 2 7.00 3.00 5.13e-5M 6.00 4.00 3.24e-5M 4 5.00 5.00 2.17e-5 5 4.00 6.00 1.45e-5M 6. 3.00 7.00 9.31e-6M 7 2.00 8.00 1.00 9.00 00

A different titration experiment using a 0.127M standardized NaOH solution to titrate a 27.67 mL solution with an unknown Molarity concentration (M) of sulfuric acid (H2SO4) gave the following molarities for 3 trials.    Initial Burette Reading (mL) Final Burette Reading (mL) Delivered vol (mL) Acid Concentration (M) Trial 1       0.0358 Trial 2       0.0341 Trial 3       0.0331 From the 3 trials, determine the average Molarity concentration of the H2SO4 to 3 significant digits. Don't include a unit. From the 3 trials, determine the standard deviation of the Molarity concentration of the H2SO4 to 3 significant digits. Don't include a unit.From the 3 trials, determine the relative standard deviation of the Molarity concentration of the H2SO4 to 3 significant digits. Don't include a unit. Do you think the above experiment was accurate? Precise? Explain your answer using supporting values.

Question: How do you expect solubility of potassium bitartrate to vary between solutions with and without KNO3?