In the Dumas Method for the determination of the molar mass of an unknown vapor, the computed percentage error of the molar mass is 1.2346. What is the true value and the experimental value, respectively, of the molar mass of the vapor in g/mol? * 58.45 and 59.1716 59.1716 and 58.45 O 58.45 and 59.2618 O 59.2618 and 60.50

What is the name of Hmc040 -1. jpgSOmc040-2.jpg?

Caffeine (C8H10O2N4 • H2O) has an absorbance of 0.510 at 272 nm and 1 cm optical path in1 mg / 100 mL concentration solutions. A 2.5 g sample of soluble coffee is diluted withwater to 500 mL. Take 250 mL, add 25.0 mL of 0.1 N H2SO4 and dilute it to 500 mL. Theabsorbance at 272 nm resulting in 0.415. A) Calculate the grams of caffeine per kg of soluble coffee in the sample. Themolar mass of caffeine is 212 g / mol.

A. Copper sulfate pentahydrate is often used to teach students about Beer’s Law by making a standard curve (linear regression). The bright blue color of the solution has a peak absorbance in the red range of the electromagnetic spectrum. The absorbance value is proportional to concentration. How many grams of CuSO4 5H2O to make up 250 mL of a 0.2 M stock of this solution? B. Using M1V1 = M2V2 how many mL would a student need to measure out in graduated cylinder to make up a 50 mL (V2) solution of 0.1M, 0.05 M, 0.025M 0.0125M solutions for a standard curve at the peak wavelenth for this compound?