Chapter 2: Problem 71
Use fundamental definitions and statements from Chapters 1 and 2 to establish the fact that \(6.022 \times 10^{23} \mathrm{u}=1.000 \mathrm{g}\)
Chapter 2: Problem 71
Use fundamental definitions and statements from Chapters 1 and 2 to establish the fact that \(6.022 \times 10^{23} \mathrm{u}=1.000 \mathrm{g}\)
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Get started for freeIodine-131 is a radioactive isotope that has important medical uses. Small doses of iodine-131 are used for treating hyperthyroidism (overactive thyroid) and larger doses are used for treating thyroid cancer. Iodine-131 is administered to patients in the form of sodium iodide capsules that contain \(^{131} \mathrm{I}^{-}\) ions. Determine the number of neutrons, protons, and electrons in a single \(^{131} \mathrm{I}^{-}\) ion.
Before \(1961,\) the standard for atomic masses was the isotope \(^{16} \mathrm{O},\) to which physicists assigned a value of exactly \(16 .\) At the same time, chemists assigned a value of exactly 16 to the naturally occurring mixture of the isotopes \(^{16} \mathrm{O},^{17} \mathrm{O},\) and \(^{18} \mathrm{O}\). Would you expect atomic masses listed in a 60 -year-old text to be the same, generally higher, or generally lower than in this text? Explain.
Germanium has three major naturally occurring isotopes: \(^{70}\) Ge \((69.92425 \mathrm{u}, 20.85 \%),^{72} \mathrm{Ge}(71.92208 \mathrm{u},\) \(27.54 \%),^{74} \mathrm{Ge}(73.92118 \mathrm{u}, 36.29 \%) .\) There are also two minor isotopes: \(^{73}\) Ge \(\left(72.92346 \text { u) and }^{76} \mathrm{Ge}\right.\) (75.92140 u). Calculate the percent natural abundances of the two minor isotopes. Comment on the precision of these calculations.
When an iron object rusts, its mass increases. When a match burns, its mass decreases. Do these observations violate the law of conservation of mass? Explain.
What is the total number of atoms in (a) 15.8 mol \(\mathrm{Fe}\); (b) \(0.000467 \mathrm{mol} \mathrm{Ag} ;\) (c) \(8.5 \times 10^{-11} \mathrm{mol} \mathrm{Na} ?\)
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