I start my day by running mixed standards using a well established method. My compounds all elute earlier than expected, there two compounds have changed their elution order, what could be the cause (multi-select)? Higher % of organic than called for Lower % of organic than called for Stronger solvent used than method called for Weaker solvent used than called for

I start my day by running mixed standards using a well established method. My compounds all elute earlier than expected, there two compounds have changed their elution order, what could be the cause (multi-select)? Higher % of organic than called for Lower % of organic than called for Stronger solvent used than method called for Weaker solvent used than called for

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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SOLVENT DISTANCE SPOTS TRAVELLED, cm 6.4 SYSTEM solvent A B 1.4 ITSAY 1.9 C 4.1 5.3 6.5 0.7 solvent A PHUKET B 1.7 2.5 В A 3.0 ITSAY PHUKET 1. Solve for the Rr values of the spots formed for each solvent. Report your answers in four significant figures. 2. Based on the resulting chromatograms after visualization with iodine vapor, which between the solvent systems ITSAY and PHUKET resulted in a more effective separation of the pigments of the indigo extract? Explain your choice.
answer both 2 parts in detail in your own to get upvote don't copy from internet/other sources I will downvote for it
Background: Given an unknown mixture which contains either two or three of the following liquids: tetrahydrofuran (THF), cyclohexane, toluene, and o-xylene. While the order that the compounds leave the column is not always obvious, the column we are using is a polar environment and therefore we would expect less polar (lower boiling) compounds to spend the least time in the column. In order to qualitatively confirm the identity of the peaks, you will make five different samples to analyze on the gas chromatograph: (a) your unknown, (b) unknown + THF, (c) unknown + cyclohexane, (d) unknown + toluene, and (e) unknown + o-xylene. Any new peak that appearsin relation to your unknown sample indicates that compound is not present in your unknown; furthermore, an increase in the size of a peak present in your unknown identifies that compound as a component of the mixture. Although not completely accurate, the areas of the peaks in your unknown will allow you to find the approximate percentage…
Extraction of Caffeine Post-lab 1. What group of organic compounds does caffeine belong to? 2. Draw the structure of caffeine as a line formula. Redraw the structure of caffeine,showing all carbon and hydrogen atoms. 3. What is the molecular formula for caffeine? Use the molecular formula of caffeine tocalculate its molecular weight. 4. What does it mean for two solvents to be immiscible? 5. On the report sheet, you calculated your percent recovery of caffeine. a. If your percent was less than 90%, give at least one reason why it was less. b. A group of students have their percent yield more than 100%, give at least one reasonwhy it was more than 100%. Do NOT simply say “human error.” Be specific about the typesof errors (human or otherwise) that may have occurred, leading to a recovery more than eorequal to 100% (Is this possible Why?) 6. Based on what you observed during this experiment, is dichloromethane denser OR lessdense than water? Explain your reasoning. 7. Based on what…
please help calculate 1-3 using given data
How would each of the following errors affect the experimental value of your molarity of acetic? Would your Molarity value be too high, too low, or unaffected? Explain your answer. if you titrated your acid sample to a bright pink rather than faint pink endpoint? if your "acetic acid" burette was still wet inside with deionized water when you filled it with acetic acid? if you recorded the final volume of NaOH as "39.88 mL" instead of "38.88 mL"?
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please i need your help A particular extraction proceeds with a distribution coefficient of 6. The system consists of 3.5 g of compound X dissolved in 60 mL of water (solvent 1). The effectiveness of three 60-mL extractions with n-hexane (solvent 2) is compared with one 180-mL extraction with n-hexane. Questions: 1. How many grams of compound X will be recovered in n-hexane in the third extraction? 2. How many grams of compound X will be recovered in water in the third extraction? 3. How many grams of compound X will be recovered in -hexane in the first extraction? 4. How many grams of compound X will be recovered in water in the first extraction?
You are given a pure unknown compound with a melting point of 118 – 120°C, which is either mandelic acid (lit. mp = 118 -120°C) or succinic anhydride (lit. mp = 119 – 120°C), along with pure samples of mandelic acid and succinic anhydride. You determine the mp of an approximately 50:50 mixture of the unknown sample and succinic anhydride to be 118-120° C. What is the identity of the unknown sample? a. succinic anhydride b. mandelic acid
mass of unknown crude for acid and neutral is 0.03 grams mass of unknown recrystallized for acid and neutral is 0.03 grams. I need help in finding overall percent
Can you help me to support this? Based on your observations of your TLC plate and FeCl3 tests, how pure is your aspirin?
Show full and complete procedure HANDWRITTEN only. Please answer a) b) and c). Note they are subparts of the same question