Postlab exp 8

A researcher has developed a new analytical method to determine the percent by mass iron in solids. To test the new method, the researcher purchases a standard reference material sample that is 2.85% iron by mass. Analysis of the iron standard returns values of 2.75%, 2.89%, 2.77%, 2.81%, and 2.87%. Are the results of the new method significantly different from the standard reference sample? (Hint: Use Confidence Interval)

Eight replicate measurements were made on a test solution producing the following results for the concentration of sodium ion (mg/L): 63.91, 65.92, 69.98, 64.24, 65.45, 65.82, 66.51, 65.11. The value 69.98 is an outlier suspect. A Q-test at 95% confidence level will lead to this conclusion with respect to the suspect value: O Should be thrown away Should not be thrown away There is not enough data to draw a conclusion None of the above

0.3414 grams of sample (crushed aspirin tablet) was weighed and dissolved in 25 mL ethanol. This solution was transferred into a 100 mL volumetric flask and filled to the mark with deionized water. 20 mL of the solution was filtered through a 0.22 μm pore filter and 503 μL of the filtered sample solution was diluted so, that the final volume of the solution was 12 mL. This sample solution and calibration solutions with known concentration of acetyl salicylic acid (ASA) were injected (injection volume 20 μL) into a HPLC and the following peak areas were measured (expressed as averages from three separate chromatographic runs): Solution Cal 1 Cal 2 Cal 3 Cal 4 Cal 5 Sample Structure of ASA: C(ASA) (mg/L) 0 OH B 53.5 105.9 140.9 195.4 247.4 Average weight of the tablet was estimated as 591.9 mg. What is the mass of ASA in one tablet? Please give the answer with 4 significant digits. Be sure you present the result with units! Peak area (mA.s) 4995 9953 12941 17271 22179 10467.3

Based on this. What was the percentage error in the percentage of water in the sample, compared to pure MgSO4•7H2O?

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Solve the equation

une Emmanuel Lab Partner(s): Martin k / Martin 0 Data Sheet volume of unknown sample (mL) mass of filter paper (g) mass of filter paper + solid Ba3(PO4)2(g) Calculation: mass of solid Ba3(PO4)2 (g) 1.885 - 0.5-1.315 Calculation: molar mass of Ba3(PO4)2 (g/mol) 737.33 (3)+30.97(2)+8(16) moles of Ba3(PO4)2 Calculation: 1323C Calculation: moles of BaCl2 Stoichiometry Lab 400mL 0.57 g 0.1.885 1.329

Part C: Determine percent Oxalic Acid in Unknown Sample Molar mass of oxalic acid 90.03 g/mol Trial 1 Trial 2 Trial 3 Average Precision Mass of unknown oxalic acid (g) 1.0048 0.9995 1.0018 --- Volume (mL) of Standardized KMNO4 used Moles of KMnO4 10.03 9.85 10.45 --- --- --- Moles of oxalic acid (H2C204 • 2H2O) --- --- grams of oxalic acid (H2C204 • 2H2O) (g) percent oxalic acid (%) --- --- Show calculations:

I need help on questions 1-2? If you can't help me on question 2, then you can help me on question 1.

Name: Date: Section: Data Report Sheet: Analysis of an Unknown Chloride Unknown # -2 Molarity of Standard Ag(NO), 5.2167x10 M Trial I Trial II Trial III Mass of Unknown 0.237 o. 232 g g Initial Burette Reading 0.00 mL 7.90 mL mL Final Burette Reading 31.00 mL 42.00 mL mL Vol. Ag(NO3) Added 31.00 mL 34.10 mL mL Moles Ag(NO,) 1.617177y10 mol. 1,7789 v10 mol. Moles CI 1.617177x103mdl. Mass Cl 0.05741 8 0g 24.22 % 27.22% Cl in Unknown Average % Cl in unknown 25.720%

I want the best value for percent purity and how did you arrive at the best value

Acetic acid percentages in five vinegar samples were 4.98, 4.86, 4.97, 4.99. 5.08, 5.11, 4.97, 5.32 and 4.89. Could we reject any of these values ​​with 95% confidence? Q critical = experimental Q = Therefore (yes or no) the suspicious data can be rejected (write the value of the data that can be deleted, example 5.08).

You have run analysis on an unknown acetaminophen sample. Your results showed the concentration of acetaminophen in the unknown was 35.9%. The actual concentration of acetaminophen in the unknown was 49.0%. What is the error % for this analysis? Answer to 1 decimal place.

A solution is prepared by diluting 2.81 mL of the blue dye stock solution to 25.00 mL. The measured absorbance for the prepared solution is listed in the data table. Measurement Result Blue dye stock solution 0.293 M Absorbance at 630 nm 0.00265 Calibration curve y=0.0833x Part: 0/3 Part 1 of 3 What is the theoretical molar concentration? Round your answer to 3 significant digits. [Blue]theoretical-M x10 X S Part: 1/3 Part 2 of 3 What is the experimental molar concentration? Round your answer to 3 significant digits. [Blue ] experimental M 9 Subm Ⓒ2022 McGraw Hill LLC. All Rights Reserved. Terms of Use Privacy Cent

Complete the table below wuth complete solution.

I need help on questions 2-3?

Given: Trial 1 25.00 0.00 10.40 10.40 Trial 2 25.0 10.40 20.13 9.73 Volume of Ca(OH)2 (mL) Initial burette reading (mL) Final burette reading (mL) Volume of HCl used in titration (mL) answer in 3 significant figures. Trial 3 25.0 20.13 30.29 (a) write the neutralization reaction involved in the experiment. (b) Calculate the molarity of Ca2+ (M). Show the complete solution. 10.16

An excess of 0.34 mg Pb is obtained from an assay test determined in an analysis. What is the percent relative error in ppt if the mass of the sample is 550 g?

An environmental scientist obtained the following replicate concentration measurements of methane (CH4) gas at a landfill site: Replicate Measurements CH4 Concentration (mg/m3) 1.0 0.1571 2.2 0.2031 3.0 0.1914 4.0 0.2103 Calculate % error when the scientific community accepts 0.2102 as true value.

4. Assuming no calculation errors, why would a percent recovery > 100% or a percent recovery < 100% be obtained? Give at least one reason for each

II. STANDARDIZATION OF NAOH SOLUTION Table 3.4. Standardization of NaOH solution. Trial 1 Conditions Trial 2 Primary standard Weight of flask, g Weight of flask + KHP, g Weight of KHP,g NaOH solution Final volume reading, mL Initial volume reading, mL 123.4568 122.4567 123.7072 122.7208 25.50 32.40 0.00 5.50 Volume used, mL Normality of NaOH solution

Determine the amount in grams of KCI that exists in 20.3 g of a solution that contains 1.14 % KCl by mass X STARTING AMOUNT RESET 3 ANSWER ADD FACTOR * ( ) 0.001 1000 %m KCI 6.022 x 10²3 20.3 mol KCI 74.55 17.8 g solution 100 1.14 g KCI 1450 1 g KCl/mol 0.272 10 0.014 23.1 0.231 0.1 0.01 Tap here or pull up for additional resources

I need help finding the %Composition for %cychohexane and %toluene. The formula (area of peak/total area) * 100%

NaOH Concentration (M): 0.09669M   Trial 1: Inital Volume of NaOH: 0.55mL Final Volume of NaOH: 28.25 mL  Trail 2:  Intial Volume of NaOH: 18.1 mL Final Volume of NaOH: 46.1 mL   Concentration of HCl Solution Subtract the initial buret reading from the end point reading. Convert the readings to liters by dividing by 1000.     Solve this equation for the concentration of HCl:                  (CHCl)  (0.01000 liters )    =     (CNaOH)  (volume of NaOH in liters).                CNaOH is the normality of the NaOH you recorded from the bottle.       Average the two HCl concentrations.

Use your average AA concentration to calculate the mass percent of acetic acid in vinegar.

Data Table Final buret reading Initial buret reading Volume used Sample 1 Vinegar Base Vinegar Sample 2 Sample 3 (if needed) Base Vinegar Base JOML Som 0,05 110mL/802 10ML 884 JUML 0.00 10μL OML Tome 0.00 10mL 80.2 mL 10ML 88mL come some *If a pipet is used to measure the volume of vinegar, record only in the space for volume used. Molarity of base (NaOH) 1685 M Vinegar number N/A CALCULATIONS: In the spaces below, show calculation setups for Sample 1 only. Show answers for both samples in the boxes. 1. Moles of base (NaOH) 2. Moles of acid (HC2H3O2) used to neutralize (react with) the above number of moles of base 3. Molarity of acetic acid in the vinegar Sample 1 Sample 2 Sample 3 (if needed) 4. Average molarity of acetic acid in the vinegar 5. Grams of acetic acid per liter (from average molarity) 6. Mass percent acetic acid in vinegar sample (density of vinegar = 1.005 g/mL) - 252 -

please help me with the answers and explain so I can understand. So, I got 0.12 but it is wrong please hepl me with this

The molarity of a solution is determined by four separate titrations or replicates, where the obtained data was 0.4120, 0.4920, 0.3920, and 0.4320 M. Calculate the standard error of the mean for the above data. O 0.00185 O 0.02160 O 0.43200 O 0.04320 O 0.01080

2.00 mL OF 5.80 x10-"M AGNO g 245.0 mL of 3.35 X10 M NazS and + Na, Scaas 2 NANO3 tazy 248.19 1549 2709 2 Ag NO3 78.19 Nans Agzs 2 NANO3 inirial Change Final

alculate the approximate volume of the vinegar sample needed for the analyses (Part A.1). Brand of vinegar or unknown no. Colauita tof White Wine Trial 1 1122809 Trial 2 Trial 1 Trial 2 e Guia 112.280g (12.822g 112.796 115 565 lis.9 1. Mass of flask (g) l15.603 2. Mass of flask + vinegar (g) 2.496 3.323 2,743 2,749 3. Mass of vinegar (g) B. Analysis of Vinegar Sample 2mL 7.5 23mL 32.コ 1. Buret reading of NaOH, initial (mL) 5.25mL 13ML amL 2. Buret reading of NaOH, final (mL) 33,3 31.2 1. Volume of NaOH used (mL) 2! mL a7.45 me 20.3 32.2 o i135 • 004 1 Molar concentration of NaOH (mol/L) Oi135 • 00 3 1003 , 063 5. Moles of NaOH added (mol) 6. Moles of CH,COOH in vinegar (mol) 7. Mass of CH,COOH in vinegar (g) 8. Percent by mass of CH,COOH in vinegar (%) 9. Average percent by mass of CH,COOH in vinegar (%) Calculations for Trial 1 of the first vinegar sample on next page. Experiment 10 137

Calculate the pH of the following solutions prepared by: Part A Dissolving 4.7 g of lithium hydroxide in water to give 290 mL of solution. Express your answer to two decimal places. pH- Submit Part B Request Answer Dissolving 0.91 g of hydrogen chloride in water to give 0.35 mL of solution. Express your answer to two decimal places. pH = Submit Bequest Answer

A chemist measured the concentration of a solution three times and obtained the following results (in mol/L): 0.0147, 0.0146, 0.0148. Do the results appear precise, accurate, or neither? Explain. avenge =.0147 (pdimus.co 120 Doy Jine What information would you need for the results to be both precise and accurate? If the true value is 0.0149, calculate the percent error.