ASSAY - 20 tablets weighing 2.58 g were crushed to a powder. A portion of the crushed powder (0.5283 g) was shaken with 50 mL of 0.1 M HCI, the mixture was filtered and made up to 100 mL. 10 ml of this solution was further diluted to 100 mL with 0.1 M HCI. The measured absorbance of the diluted solution at 276 nm was 0.582. Additional information: A196 = 72.3, stated content = 20 mg Calculate:

ASSAY - 20 tablets weighing 2.58 g were crushed to a powder. A portion of the crushed powder (0.5283 g) was shaken with 50 mL of 0.1 M HCI, the mixture was filtered and made up to 100 mL. 10 ml of this solution was further diluted to 100 mL with 0.1 M HCI. The measured absorbance of the diluted solution at 276 nm was 0.582. Additional information: A196 = 72.3, stated content = 20 mg Calculate:

Chemistry: The Molecular Science

5th Edition

ISBN:9781285199047

Author:John W. Moore, Conrad L. Stanitski

Publisher:John W. Moore, Conrad L. Stanitski

Chapter2: Chemical Compounds

Section: Chapter Questions

Problem 105QRT

See similar textbooks

Similar questions

This year, like many past years, you begin to feel very sleepy alter eating a large helping of Thanksgiving turkey. Some people attribute this sleepiness to the presence of the amino acid tryptophan in turkey. Tryptophan can be used by the body to produce serotonin, which can calm the brains activity and help to bring on sleep. a. What mass in grams of tryptophan is in a 0.25-lb serving of turkey? (Assume tryptophan accounts for 1.0% of the turkey mass.) b. What mass in grams of tryptophan is in 0.25 quart of milk? (Assume tryptophan accounts for 2.0% of milk by mass and that the density of milk is 1.04 kg/L.)
A material is believed to be a compound. Suppose you have several samples of this material obtained from various places around the world. Comment on what you would expect to find upon observing the melting point and color for each sample. What would you expect to find upon determining the elemental composition for each sample?
1.87 A solution of ethanol in water has a volume of 54.2 mL and a mass of 49.6 g. what information would you need to look up and how would you determine the percentage of ethanol in this solution?
Potassium sulfate has a solubility of 15 g/ 100 g water at 40C. A solution is prepared by adding 39.0 g of potassium sulfate to 225 g of water, carefully heating the solution, and cooling it to 40C. A homogeneous solution is obtained. Is this solution saturated, unsaturated, or supersaturated? The beaker is shaken, and precipitation occurs. How many grams of potassium sulfate would you expect to crystallize out?
1.82 Which of the following molecular-scale diagrams best represents a pure compound? Explain your answer.
A 15.5 g sample of sodium carbonate is added to a solution of acetic acid weighing 19.7 g. The two substances react, releasing carbon dioxide gas to the atmosphere. After reaction, the contents of the reaction vessel weigh 28.7 g. What is the mass of carbon dioxide given off during the reaction?
Some bottles of colorless liquids were being labeled when the technicians accidentally mixed them up and lost track of their contents. A 15.0-mL sample withdrawn from one bottle weighed 22.3 g. The technicians knew that the liquid was either acetone, benzene, chloroform, or carbon tetrachloride (which have densities of 0.792 g/cm3, 0.899 g/cm3, 1.489 g/cm3, and 1.595 g/cm3, respectively). What was the identity of the liquid?
Which of the following represent physical properties or changes, and which represent chemical properties or changes? You curl your hair with a curling iron. You curl your hair by getting a “permanent wave” at the hair salon. Ice on your sidewalk melts when you put salt on it. A glass of water evaporates overnight when it is left on the bedside table. Your steak chars if the skillet is too hot. Alcohol feels cool when it is spilled on the skin. Alcohol ignites when a flame is brought near it. Baking powder causes biscuits to rise.
On October 21, 1982, the Bureau of the Mint changed the composition of pennies (see Exercise 120). Instead of an alloy of 95% Cu and 5% Zn by mass, a core of 99.2% Zn and 0.8% Cu with a thin shell of copper was adopted. The overall composition of the new penny was 97.6% Zn and 2.4% Cu by mass. Does this account for the difference in mass among die pennies in Exercise 120? Assume the volume of the individual metals that make up each penny can be added together to give the overall volume of the penny, and assume each penny is the same size. (Density of Cu = 8.96 g/cm3; density of Zn = 7.14 g/cm3).
In what country is most of the world’s cobalt mined? What events in that country dramatically affected the price of cobalt?