(Concentration) You are tasked to prepare 50.000 ppm of a caffeine standard for an analysis. If you need to prepare 500.00 (±0.08) mL of this solution, how much (in grams) solid, pure caffeine are you supposed to dissolve? What absolute uncertainty is associated with your mass measurement if the prepared solution has a 0.12% percent relative uncertainty? Write your answer using the appropriate number of digits. Note that the formula mass of caffeine is 194.194 g/mol with negligible error. (absolute error) --- How many significant figures does your reported mass have? (number of sig. figs.) --- ---

(Concentration) You are tasked to prepare 50.000 ppm of a caffeine standard for an analysis. If you need to prepare 500.00 (±0.08) mL of this solution, how much (in grams) solid, pure caffeine are you supposed to dissolve? What absolute uncertainty is associated with your mass measurement if the prepared solution has a 0.12% percent relative uncertainty? Write your answer using the appropriate number of digits. Note that the formula mass of caffeine is 194.194 g/mol with negligible error. (absolute error) --- How many significant figures does your reported mass have? (number of sig. figs.) --- ---

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter16: Applications Of Neutralization Titrations

Section: Chapter Questions

Problem 16.18QAP

See similar textbooks

Similar questions

A stock solution of 0.225 +/- 0.003 M NaNO2 was transferred to a 100 mL volumetric flask (class A) and diluted to the mark. If 7 mL of the stock solution was transferred using one 5-mL and two 1-mL volumetric pipettes, what is the new concentration of the solution and the uncertainty?
I would need help with these questions. The method referenced above was followed by a student and she got the following results: Caffeine Std. Conc. (ppm) Absorbance 100 1.806 50 0.899 40 0.724 30 0.545 20 0.365 10 0.183 Further, she analyzed an unknown sample and she got the following results: Sample # Absorbance 1 0.398 1. Graphically find the concentration in ppm and then calculate in mol/L of Caffeine in Sample #1? 2. Which solvent was used to extract Caffeine and why? Why is it necessary to do extraction three times? 3. Cuvettes used in this experiment were made from which material and why? 4. At what wavelength the Absorbance was measured?
potassium hydrogen phthalate is a primary standard used to measure the concentration of NaOH solutions. find the true mass of potassium hydrogen phthalate (density=1.636g/ml) if the mass weighed in the air is 4.236g. if you did not correct the mass for buoyancy, would the calculated molarity be too high or too low? the density of air is 0.0012 g/mL while that of the calibration weights is 8.0 g/mL.
An analysis of city drinking water for total hardness was done by two students in the laboratory and produced the following results (in ppm CaCO3): Student A: 228.3, 226.4, 226.9, 227.1, and 228.6. Student B: 229.5, 226.1, 230.7, 223.8, and 227.5What is the 95% confidence interval for the mean?
A. A group of students are doing an analysis of copper in 1-peso coin. They were tasked to prepare standard solutions and weigh the analyte as the end-product of their experiment. Explain the type of error they are incurring in their experiment. A. Marikit had very good precision but poor accuracy in her data. B. Volumetric flasks were placed inside the oven for drying before it was used. C. Trial 1 and 2 have values close to 30.0 mL while trial 3 gave 55.0 mL. D. The reagent used in determining copper was added incorrectly and gave a low yield.
A variation of the indicator-dilution method (see preceding problem) is used to measure total blood volume. A known amount of a tracer is injected into the bloodstream and disperses uniformly throughout the circulatory system. A blood sample is then withdrawn, the tracer concentration in the sample is measured, and the measured concentration [which equals (tracer injected)/(total blood volume) if no tracer is lost through blood vessel walls] is used to determine the total blood volume.In one such experiment, 0.60 cm3 of a solution containing 5.00 mg/L of a dye is injected into an artery of a grown man. About 10 minutes later, after the tracer has had time to distribute itself uniformly throughout the bloodstream, a blood sample is withdrawn and placed in the sample chamber of a spectrophotometer. A beam of light passes through the chamber, and the spectrophotometer measures the intensity of the transmitted beam and displays the value of the solution absorbance (a quantity that…
A second spectrophotometric method for the quantitative analysis of Pb2+ in blood yields an Ssamp of 0.712 for a 5.00 mL sample of blood. After spiking the blood sample with 5.00 μL of a 1560 ppb Pb2+ external standard, an Sspike of 1.546 is measured. What is the concentration of Pb2+ in the original sample of blood?
In the determination of the concentration of chloride ion in water five experiments were done: 254.3 ppm, 254.7 ppm, 249.9 ppm, 252.5 ppm, and 253.4 ppm. What is the relative average deviation of this experiment? (ppm=mg/L
1. What is the MW of the analyte?2. What is the meq of the analyte?3. What will be the weight (in grams) of the analyte if the standardization is to be quartered?4. What will be Normality of the solution if 7.5ml of the titrant was consumed in the standardization?5. What is the average Normality if two or more trials were conducted with the values of 0.102N and 0.105N?
If an instrument gives a response of 1240 for a standard containing 8 ppm of a substance, how much if this substance is in a sample that gives a response of 1705? Are any assumptions needed?
25 ml of pickled brine was taken from an apple pickled with vinegar and diluted to 500 ml, 25 ml of this was taken and acidity was determined with 0.2 N (Factor: 1.05) NaOH. In the main trials, 6.3 ml - 6.5 ml - 6.9 ml, respectively, 0.1 ml base was used in the analysis without using the sample.For example, how many ppm is its acidity?
When answering this problem, report the answer with the appropriate number of significant figures. When entering units, use proper abbreviated units with proper capitalization. A beverage drink mix sample is prepared by mixing a packet of beverage powder in a gallon (3.78 L) of water. A sample for analysis is prepared by diluting 10.00 mL of this solution in a 50.0 mL volumetric flask. When measured using a colorimeter, this diluted solution has an absorbance of 0.349. The calibration curve for the experiment yielded a linear fit of y = 21655x+0.0318 and an R2 value of 0.9911. Determine the molar concentration of food dye in the analyzed sample. Answer: _____x10____ _____units