Copy of 5AL Lab 5 Submission Template - F23v2

■ True or False: in a TOF analyzer, a fragment of low mass reaches the detector first ▪ In GCMS when we know what analytes we are measuring we use not know what analytes are in the sample we use than scan. ▪ A) Scan; SIM ■ B)SIM; scan • C) SIM; SIM mode. When we do mode. SIM allows greater sensitivity

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Please let me know which 2 answers are correct, an explanation including evidence

The absorbance of a cationic iron(II) sample solution was measured in a spectrophotometer, but the instrument returned an error because the absorbance was too high. The sample was then diluted by using a pipette to take 100.0 μL�L of the sample and injecting it into a cuvette already containing 2.00 mLmL of water (total volume is 2.00 mLmL + 100.0 μL�L). The absorbance value of the diluted solution corresponded to a concentration of 6.22×10−6  M � . What was the concentration of the original solution?

The following volumes of 0.000300 M SCN are diluted to 15.00 mL. Determine the concentration of SCN in each sample after dilution. These values will be used during the experiment. To enter exponential values, use the format 1.0e-5. Sample 0.000300 M SCN (mL) [SCN'] (M) 1 1.50 3.50 7.00 4 10.00 3.

You have a stock solution of 150.0±0.3 mg SO²/mL that has been certified by the manufacturer. You decide to dilute the solution by a factor of 100 to get a final concentration of 1.500 mg/mL. To do this, you use a 1.000±0.006 mL transfer pipette to transfer your stock solution to a 100.000.08 mL volumetric flask that you then dilute to the mark. Please calculate the absolute and relative error for the final concentration.

7 please

The method of standard additions was used to determine nitrite in a soil sample. A 1.00-mL portions of the soil extract sample was transferred to four 25-mL volumetric flasks. To each flask, increment volumes of a 1.00 x10-3M nitrite was added according to the table below. A colorimetric reagent was added to each flask to convert the nitrite into a colored product, and finally diluted to volume. What is the concentration of the nitrite in the soil extract based on the absorbance data below (with blank correction included)? Vol. of standard nitrite added, ml Absorbance 5.00 0.079 10.00 0.161 15.00 0.236 20.00 0.318 25.00 0.403

Q3: In a chromatographic analysis, a solution was prepared with 0.0837 M Octane (A) and 0.0666 M nonane (B). Each one produced a peak area of AA = 423 and AB = 347.10.0 ml of 0.146 M nonane was added to 10 ml of an unknown sample, and the sample diluted to 25 ml. The peak areas obtained were AA = 553 and AB = 582. What is the concentration of Octane in the unknown sample?

In order to understand how this equation is derived and why it holds true, the product of each side of the equation should be examined. What value and unit do you get when you multiply a concentration of 0.514 Mby a volume of 0.100 L? This question can be expressed as 0.100 L x 0.514 mol 1 Express your answer to three significant figures with the appropriate units. • View Available Hint(s) HẢ ? M1V1 = Value Units %3D Submit Part B When you need to produce a variety of diluted solutions of a solute, you can dilute a series of stock solutions. A stock solution has a significantly higher concentration of the given solute (typically 10' to 104 times higher than those of the diluted solutions). The high concentration allows many diluted solutions to be prepared using minimal amounts of the stock solution. What volume of a 6.56 M stock solution do you need to prepare 500. mL of a 0.0842 M solution of KC? Express the volume to three significant figures with the appropriate units. • View…

The absorbance of a cationic iron(II) sample solution was measured in a spectrophotometer, but the instrument returned an error because the absorbance was too high. The sample was then diluted by using a pipette to take 100.0 μLμL of the sample and injecting it into a cuvette already containing 2.00 mLmL of water (total volume is 2.00 mLmL + 100.0 μLμL). The absorbance value of the diluted solution corresponded to a concentration of 7.71×10−6  M M . What was the concentration of the original solution? Express the concentration to three significant figures with the appropriate units.

You begin preparation of the calibration curve to measure absorbance vs concentration of FeSCN²+. To do so, you add 1.58 mL of 0.200 M Fe(NO3)3 to a cuvette and then directly add 316 µL of 0.001 M KSCN. What is the resulting concentration of FeSCN2+, assuming complete conversion of SCN´¯ to FeSCN²+´ Enter your answer in units of mM to four digits after the decimal.

To run a spectrophotometry experiment, begin by warming up the spectrophotometer and preparing the samples. Be sure to select the correct absorbance (X), then run a measurement on the sample solution. Follow up by running measurements on sample solutions. Once data is collected, turn off the instrument, clean the area, and discard the samples. Partially correct (2 of 4 correct)

Julie has been asked to measure the concentration of a sample solution using a spectrophotometer. After a first attempt, she realizes that, to make the measurement, she must first dilute the sample solution. Julie transfers 1.3 mL1.3 mL of the sample to a 250 mL250 mL volumetric flask and fills the rest of the flask with water to the 250 mL250 mL line. She then uses the spectrophotometer to measure the concentration of the dilute solution as 5.5×10−5 M.5.5×10−5 M. What is the concentration of the starting sample solution?

professor Scimemi has accepted you as a Master’s student and you are involved in a project that studies the cellular basis of neuropsychiatric diseases. For your electrophysiology recordings you have to make a recording solution containing (in mM): 119 NaCl, 2.5 KCl, 2.5 CaCl2, 1 MgCl2, 26.2 NaHCO3, 1 NaH2PO4, 22 glucose. You need 800 ml of it. How much KCl do you need to weigh out? Hint: we only care about KCl here. (MW KCl is 74.55 g/mol

28 Report Sheet Separation of the Components of a Mixture D. Determination of Percent Recovery Mass of original sample 10.588 Mass of determined (NH Cl+ NaCl+ SiO2) 1-88 8 Differences in these weights g matter recovered Percent recovery of matter %3D = %00 % g original sample Account for your errors. Combor QUESTIONS 1. Could the separation in this experiment have been done in a different order? For example, if the mixture was first extracted with water and then both the extract and the insoluble residue were heated to dryness, could you determine the amounts of NaCl, NH,Cl, and SiO, originally present? Why or why not? Consult a handbook to answer these questions. 2. How could you separate barium sulfate, BaSO4, from NaCl? 3. How could you separate magnesium chloride, MgCl2, from silver chloride, AgCl? 4. How could you separate tellurium dioxide, TeO2, from SiO,? 5. How could you separate lauric acid from a-naphthol? (See Table 3.1.)

2 What methods are used to sep X G In Part Il of experiment 5, a 1:1: X + u/ultra/courses/_393452_1/cl/outline * Question Completion Status: QUESTION 3 After you complete the second step, you will be left with a clear colorless liquid. What should be done to the liquid to finish the separation? O Heat the mixture to evaporate the liquid O Add a base to neutralize the solution. O Nothing - you are done since you have a pure, clear, colorless substance O Add the residue back to the solution and dry. QUESTION 4 In Part II of experiment 5, a 1:1:1 mixture of sand, salt, and salicylic acid must be separated. Order the following steps necessary to separate this mixture into three pure, dry solids. Filter the liquid leaving a filtrate with just salt dissolved and a residue of sand. v Add hot water to the residue obtained in two steps prior to this one. Filter the liquid leaving a filtrate with just salicylic acid dissolved and a residue of salt and sand. v Heat the filtrate obtained in two…

What is the difference between a decigram balance and an analytical balance?

A sample was placed on a chromatography column. Methylene chloride was used as the eluting solvent. No separation of the components in the sample was observed. What must have been happening during this experiment? How would you change the experiment to overcome this problem?

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Julie has been asked to measure the concentration of a sample solution using a spectrophotometer. After a first attempt, she realizes that, to make the measurement, she must first dilute the sample solution. Julie transfers 2.3 mL2.3 mL of the sample to a 250 mL250 mL volumetric flask and fills the rest of the flask with water to the 250 mL250 mL line. She then uses the spectrophotometer to measure the concentration of the dilute solution as 5.5×10−5 M.5.5×10−5 M. What is the concentration of the starting sample solution? sample solution concentration:   M

From the data in Table 2.5, compute the concentration of the undiluted and diluted ovalbumin samples (make sure to account for the appropriate dilution factors, DF, in the computation).

Pre-lab 1. In your own words, what is accuracy and precision? Why are they important in the clinical lab?