Question

Consider the following isotopic abundance data for argon (Ar) and silicon (Si):

Argon Isotope Isotopic Molar Mass 36 Ar 35.96755 g/mol Ar 37.96272 g/mol 40 Ar 39.96240 g/mol Abundance 0.337% 0.063% 99.600% Silicon Isotope Isotopic Molar Mass 25 Si 27.97693 g/mol 29 Si 28.97649 g/mol 30 Si 29.97376 g/mol Abundance 92.23% 4.67% 3.10%
Use the data to calculate the atomic masses of naturally occurring argon and silicon.
b) Calculate the number of atoms in 78.2 g of naturally occuring Si.
c) 42Ar is one of the longest lived radioactive isotopes of Argon. Mass spectroscopy data yields the following ratio of the mass of 42Ar to 40Ar: Mass of 42Ar Mass of 40Ar = 1.05006 use this ratio to find the atomic mass of 42Ar.
2. Pantoprazole, first sold under the brand name Protonix, is used for short-term treatment of erosive esophagitis associated with gastroesophageal reflux disease (GERD). The chemical formula for pantoprazole is C16H15F2N3O4S a) What is the molar mass of pantoprazole? b) How many molecules are in a 0.078 g sample of panotprazole?

Answer 1

It's too short. Write at least 20 characters to explain it well.

Step-by-step explanation:

Hold on, our servers are swamped. Wait for your answer to fully load.

Answer 2

Step-by-step explanation:

Molar mass of Argon

= 35.96755 x .00337 + 37.96272 x .00063 + 39.96240 x .99600

= .12121 + .0239165 + 39.80255

= 39.95

Molar mass of silicon

27.97693 x .9223 + 28.97649 x .0467 + 29.97376 x .0310

= 25.803 + 1.35320 + .929

= 28.08

b )

No of atoms of Si in 78.2 g = 78.2 x 6.02 x 10²³ / 28.08

= 16.76 x 10²³ .

c )

42 Ar / 40 Ar = 1.05006

42 Ar / 39.95 = 1.05006

42Ar = 41.95

2 )

C₁₆H₁₅F₂N₃O₄S

Mol weight = 16 x 12 + 1 x 15 + 2 x 19 + 3 x 14 + 4 x 16 + 32

= 192 + 15 + 38 + 42 + 64+ 32

= 383

No of molecules = .078 x 6.02 x 10²³ / 383

= 1.226 x 10²⁰ molecules .