Ch.2 - Atoms & ElementsWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: Use the mass spectrum of mercury to estimate the atomic mass of mercury.Estimate the masses and percent intensity values from the graph to three significant figures.

Solution: Use the mass spectrum of mercury to estimate the atomic mass of mercury.Estimate the masses and percent intensity values from the graph to three significant figures.

Problem

Use the mass spectrum of mercury to estimate the atomic mass of mercury.

Mass spectrum of mercury with percent intensity on the vertical axis and mass (amu) on the horizontal axis. The spectrum includes the percent intensities of seven isotopes of mercury: Hg-196 with a peak intensity of about 5.0%; Hg-198 with a peak intensity of about 35%; Hg-199 with a peak intensity of about 55%; Hg-200 with a peak intensity of 75%; Hg-201 with a peak intensity of about 35%; Hg-202 with a peak intensity of 100%; and Hg-204 with a peak intensity of 25%.

Estimate the masses and percent intensity values from the graph to three significant figures.

Solution

Mass spectrometry is often used to determine the atomic mass of an element. Recall that the atomic mass of an element depends on the relative abundance of each isotope.

From the figure, we can estimate the intensity of the signal for each isotope:

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