Recent questions in Analytical Chemistry

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1 answer 163 views

A chemistry student needs to identify an unknown compound found at a crime scene using mass spectrometry. The compound has a molecular weight of 286 g/mol and the mass spectrum shows a strong peak at m/z = 180 and a weaker peak at m/z = 148. What is the possible molecular formula of the unknown compound?

asked Jan 22 in Analytical Chemistry by August936905 (1.5k points)

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1 answer 34 views

A chemistry student needs to determine the pH of an unknown solution using a pH meter. The student is given the following equipment: pH meter, reference electrode, and a container for the solution. The student should describe the steps needed to measure the pH of the solution and explain the significance of the obtained pH value.

asked Jan 22 in Analytical Chemistry by MaxwellDuff3 (1.9k points)

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1 answer 95 views

A chemistry student needs to determine the pH of a solution using a pH meter. The student has to prepare a buffer solution of pH 7.0 using 0.1M acetic acid and 0.1M sodium acetate. The student is then required to measure the pH of the prepared buffer solution using a pH meter and record the observations. Finally, the student has to compare the pH value obtained by the pH meter with the calculated pH value of the prepared buffer solution and explain any deviations observed.

asked Jan 22 in Analytical Chemistry by OrenTherrien (1.8k points)

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1 answer 107 views

A chemistry student needs to determine the percentage of iron (Fe) present in a given iron ore sample using gravimetric analysis. The student is provided with the mass of the iron ore sample and a standardized solution of potassium dichromate (K2Cr2O7) to use for the analysis. What is the percentage of iron (Fe) in the given iron ore sample?

asked Jan 22 in Analytical Chemistry by SimonMcWilli (1.9k points)

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1 answer 79 views

A chemistry student needs to determine the percentage of calcium carbonate (CaCO3) present in a mixture of calcium carbonate and calcium phosphate. The student has the following information: A 1.00-gram sample of the mixture was dissolved and reacted with excess hydrochloric acid (HCl), producing 0.236 grams of carbon dioxide (CO2) gas. The balanced chemical equation for the reaction is: CaCO3 + 2HCl → CaCl2 + CO2 + H2O. The student also knows that the molecular weight of CaCO3 is 100.09 g/mol and that of Ca3(PO4)2 is 310.18 g/mol. What is the percentage of calcium carbonate in the mixture?

asked Jan 22 in Analytical Chemistry by Alexis87J090 (1.6k points)

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1 answer 82 views

A chemistry student needs to determine the percent composition of nitrogen (N) in a sample of an unknown organic compound. Using elemental analysis, the student determines the mass of the sample to be 0.254 g and the mass of the products after combustion to be 0.727 g of CO2 and 0.298 g of H2O. What is the percent composition of nitrogen in the sample?

asked Jan 22 in Analytical Chemistry by DanielleSauc (2.4k points)

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1 answer 93 views

A chemistry student needs to determine the percent by mass of magnesium (Mg) in a sample of limestone. The student has access to 5 grams of the sample and is provided with the following information: the sample is comprised of calcium carbonate (CaCO3) and magnesium carbonate (MgCO3); the atomic masses of the elements are: Ca = 40.08 g/mol, C = 12.01 g/mol, O = 16.00 g/mol, and Mg = 24.31 g/mol; and the sample contains a total of 3.06 grams of carbon (C). Calculate the percentage by mass of magnesium in the limestone sample using mass balance calculations.

asked Jan 22 in Analytical Chemistry by TereseAbner (1.8k points)

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1 answer 117 views

A chemistry student needs to determine the concentration of silver nitrate (AgNO3) in a given sample from the following information:- A 10 mL sample of 0.1 M sodium chloride (NaCl) was mixed with excess silver nitrate.- The resulting precipitate was filtered, washed, and dried. The mass of the precipitate was found to be 0.212 g.- The molar mass of AgNO3 is 169.87 g/mol.What is the concentration of AgNO3 in the original sample?

asked Jan 22 in Analytical Chemistry by Tesha44V4191 (1.7k points)

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1 answer 114 views

A chemistry student needs to determine the concentration of NaOH in a 250 mL solution. They know that 10 mL of the solution was titrated with 0.1 M HCl solution, which required 8.5 mL of the HCl solution to be fully neutralized. Based on this information, what is the concentration of NaOH in the solution?

asked Jan 22 in Analytical Chemistry by Lachlan74F5 (2.0k points)

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1 answer 80 views

A chemistry student needs to determine the concentration of iron (III) ions in a water sample using spectrophotometry. The water sample contains an unknown amount of iron (III) ions that need to be quantified with a high degree of accuracy. The student has access to a spectrophotometer and an iron (III) ion standard solution to be used as a reference for the analysis. What is the concentration of iron (III) ions in the water sample?

asked Jan 22 in Analytical Chemistry by ErnestinaMus (1.9k points)

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1 answer 112 views

A chemistry student needs to determine the concentration of a copper sulfate solution by using mass balance calculations. The student knows that a 100 mL sample of the solution at an unknown concentration was diluted to 500 mL, and then 50 mL of the diluted solution was titrated with a standardized sodium thiosulfate solution. The titre value was 10.0 mL. The student needs to determine the concentration of the copper sulfate solution in terms of grams per liter (g/L).

asked Jan 22 in Analytical Chemistry by AleidaSeifer (1.7k points)

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1 answer 66 views

A chemistry student needs to determine the concentration of a certain analyte in a water sample using colorimetry. The student has access to a spectrophotometer and a standard calibration curve. What is the concentration of the analyte in the water sample, given its absorbance value in the spectrophotometer and the calibration curve data?

asked Jan 22 in Analytical Chemistry by AWSReginald (2.2k points)

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1 answer 115 views

A chemistry student needs to determine the composition of a sample that contains an unknown mixture of sodium chloride (NaCl) and potassium chloride (KCl). The student weighs 2.00 g of the mixture and dissolves it in water to obtain a solution. The student then precipitates the chloride ions from the solution with excess silver nitrate (AgNO3) to obtain 6.50 g of silver chloride (AgCl). Using mass balance calculations, determine the mass and percentage composition of the sodium chloride and potassium chloride in the mixture.

asked Jan 22 in Analytical Chemistry by KreogMoore5 (6.4k points)

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1 answer 89 views

A chemistry student needs to analyze the composition of a soil sample using elemental analysis. The student has to determine the percentage of carbon, nitrogen, and sulfur present in the sample. How can the student perform elemental analysis and calculate the percentage of each element in the soil sample accurately?

asked Jan 22 in Analytical Chemistry by KrystleDHage (2.0k points)

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1 answer 80 views

A chemistry student needs to analyze a water sample to determine the concentration of a certain contaminant. The student knows the initial concentration of the contaminant in the source water and the volume of the source water used to produce the final sample. Can the student use mass balance calculations to determine the concentration of the contaminant in the final water sample? If so, what is the concentration of the contaminant in the final sample?

asked Jan 22 in Analytical Chemistry by KyleWaddy213 (1.9k points)

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1 answer 94 views

A chemistry student needs to analyze a sample of a mixture that consists of anionic and cationic species. Using capillary electrophoresis, determine the presence and concentration of each species in the sample. Additionally, suggest a suitable buffer system and optimize the electrophoresis conditions for efficient separation and detection of the species.

asked Jan 22 in Analytical Chemistry by AntonioDaven (1.7k points)

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1 answer 105 views

A chemistry student is provided with a mixture of two chemicals, A and B, but the quantity of each chemical is unknown. The student uses mass balance calculations to determine the mass of each component in the mixture. Chemical A has a molecular weight of 100 g/mol, while chemical B has a molecular weight of 120 g/mol. If the mixture contains 10% more of chemical A by mass than chemical B, what is the mass of each component in the mixture?

asked Jan 22 in Analytical Chemistry by MatthewStore (1.3k points)

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1 answer 74 views

A chemistry student is given an unknown mystery organic compound and is asked to identify it using mass spectrometry. The student must explain the steps they would take with a mass spectrometer to accurately determine the compound’s identity and provide a detailed analysis of the results obtained.

asked Jan 22 in Analytical Chemistry by LSCJoey08837 (2.2k points)

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1 answer 121 views

A chemistry student is given an unknown compound and is required to identify its molecular structure using mass spectrometry. How can the student analyze the mass spectrum data to determine the compound's molecular weight and possible functional groups?

asked Jan 22 in Analytical Chemistry by WallaceMaria (2.4k points)

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1 answer 102 views

A chemistry student is given an unknown compound and is asked to identify its molecular formula using mass spectrometry. The compound has a molecular ion peak at m/z 86 and fragments at m/z 43 and 58. What is the molecular formula of the unknown compound?

asked Jan 22 in Analytical Chemistry by LeeAlder0448 (1.5k points)

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