Mass Spectra of Elements - AP Chemistry
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Determine the isotopic composition of chlorine using its mass spectrum.
Determine the isotopic composition of chlorine using its mass spectrum.
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Peaks at m/z = 35 and 37. Shows $^{35}$Cl and $^{37}$Cl isotopes in 3:1 ratio.
Peaks at m/z = 35 and 37. Shows $^{35}$Cl and $^{37}$Cl isotopes in 3:1 ratio.
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How is the molecular ion peak identified in a mass spectrum?
How is the molecular ion peak identified in a mass spectrum?
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It is the peak with the highest m/z value. The rightmost peak shows the intact molecule's mass.
It is the peak with the highest m/z value. The rightmost peak shows the intact molecule's mass.
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What is the typical charge state observed in a mass spectrum?
What is the typical charge state observed in a mass spectrum?
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+1. Most ions have single positive charge from electron loss.
+1. Most ions have single positive charge from electron loss.
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What does a cluster of peaks in a mass spectrum suggest?
What does a cluster of peaks in a mass spectrum suggest?
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Presence of isotopic variants. Multiple isotopes create pattern of related peaks.
Presence of isotopic variants. Multiple isotopes create pattern of related peaks.
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Determine the presence of sulfur isotopes in a mass spectrum.
Determine the presence of sulfur isotopes in a mass spectrum.
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Look for peaks at m/z = 32, 33, 34. Sulfur has isotopes $^{32}$S, $^{33}$S, and $^{34}$S.
Look for peaks at m/z = 32, 33, 34. Sulfur has isotopes $^{32}$S, $^{33}$S, and $^{34}$S.
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What can cause broad peaks in a mass spectrum?
What can cause broad peaks in a mass spectrum?
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Instrumental resolution limitations. Poor resolution cannot separate closely spaced m/z values.
Instrumental resolution limitations. Poor resolution cannot separate closely spaced m/z values.
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How can isotopic ratios be determined from a mass spectrum?
How can isotopic ratios be determined from a mass spectrum?
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By comparing relative peak heights. Peak height ratios show isotopic abundance ratios.
By comparing relative peak heights. Peak height ratios show isotopic abundance ratios.
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Identify the peak corresponding to the molecular ion of methane (CH₄).
Identify the peak corresponding to the molecular ion of methane (CH₄).
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Peak at m/z = 16. Methane molecular ion has mass 16 amu.
Peak at m/z = 16. Methane molecular ion has mass 16 amu.
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How does a mass spectrometer identify different isotopes?
How does a mass spectrometer identify different isotopes?
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By their distinct m/z values. Each isotope has unique mass giving distinct m/z value.
By their distinct m/z values. Each isotope has unique mass giving distinct m/z value.
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What is the function of the magnetic field in a mass spectrometer?
What is the function of the magnetic field in a mass spectrometer?
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To deflect ions based on m/z. Creates force that separates ions by mass-to-charge ratio.
To deflect ions based on m/z. Creates force that separates ions by mass-to-charge ratio.
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What does a low abundance peak in a mass spectrum indicate?
What does a low abundance peak in a mass spectrum indicate?
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Less common isotope or fragment. Shows minor isotope or molecular fragmentation product.
Less common isotope or fragment. Shows minor isotope or molecular fragmentation product.
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Which factor affects the degree of ion deflection in a mass spectrometer?
Which factor affects the degree of ion deflection in a mass spectrometer?
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Mass-to-charge ratio (m/z). Determines how much ions deflect in the magnetic field.
Mass-to-charge ratio (m/z). Determines how much ions deflect in the magnetic field.
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Which element's isotopes can be separated using mass spectrometry?
Which element's isotopes can be separated using mass spectrometry?
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Any element with isotopes. Mass spectrometry can separate isotopes of all elements.
Any element with isotopes. Mass spectrometry can separate isotopes of all elements.
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What is the charge of ions detected in a mass spectrometer?
What is the charge of ions detected in a mass spectrometer?
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Typically +1 charge. Single positive charge from electron removal during ionization.
Typically +1 charge. Single positive charge from electron removal during ionization.
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Describe the main stages of a mass spectrometer.
Describe the main stages of a mass spectrometer.
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Ionization, acceleration, deflection, detection. Sequential steps that separate and detect ions by mass.
Ionization, acceleration, deflection, detection. Sequential steps that separate and detect ions by mass.
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What is the role of acceleration in mass spectrometry?
What is the role of acceleration in mass spectrometry?
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To give ions kinetic energy. Accelerated ions can be deflected by magnetic fields.
To give ions kinetic energy. Accelerated ions can be deflected by magnetic fields.
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What does the x-axis represent in a mass spectrum?
What does the x-axis represent in a mass spectrum?
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Mass-to-charge ratio (m/z). Shows the mass divided by charge for each ion detected.
Mass-to-charge ratio (m/z). Shows the mass divided by charge for each ion detected.
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Identify the ionization method used in mass spectrometry.
Identify the ionization method used in mass spectrometry.
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Electron impact ionization. High-energy electrons remove electrons from atoms/molecules.
Electron impact ionization. High-energy electrons remove electrons from atoms/molecules.
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How are ions detected in a mass spectrometer?
How are ions detected in a mass spectrometer?
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By measuring their abundance as electrical signals. Ion collisions create electrical current proportional to abundance.
By measuring their abundance as electrical signals. Ion collisions create electrical current proportional to abundance.
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What information does a mass spectrum provide about an element?
What information does a mass spectrum provide about an element?
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Isotopic composition and abundance. Shows which isotopes exist and their relative amounts.
Isotopic composition and abundance. Shows which isotopes exist and their relative amounts.
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What is the purpose of the detector in a mass spectrometer?
What is the purpose of the detector in a mass spectrometer?
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To measure the abundance of ions. Converts ion impacts into measurable electrical signals.
To measure the abundance of ions. Converts ion impacts into measurable electrical signals.
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What does the term 'base peak' mean in mass spectrometry?
What does the term 'base peak' mean in mass spectrometry?
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The tallest peak representing 100% relative abundance. The peak set to 100% for comparing other peak heights.
The tallest peak representing 100% relative abundance. The peak set to 100% for comparing other peak heights.
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What is the unit for mass-to-charge ratio in mass spectrometry?
What is the unit for mass-to-charge ratio in mass spectrometry?
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Atomic mass units per charge (amu/e). Standard unit expressing mass per unit charge.
Atomic mass units per charge (amu/e). Standard unit expressing mass per unit charge.
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How is the resolution of a mass spectrometer defined?
How is the resolution of a mass spectrometer defined?
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Ability to distinguish between close m/z values. Measures ability to separate peaks with similar m/z values.
Ability to distinguish between close m/z values. Measures ability to separate peaks with similar m/z values.
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Find the relative atomic mass given isotopic masses and abundances.
Find the relative atomic mass given isotopic masses and abundances.
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Calculate using $\text{RAM} = \frac{\text{sum of (m/z) × abundance}}{\text{total abundance}}$. Weighted average formula using isotopic masses and abundances.
Calculate using $\text{RAM} = \frac{\text{sum of (m/z) × abundance}}{\text{total abundance}}$. Weighted average formula using isotopic masses and abundances.
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Which isotope of carbon is most abundant, based on mass spectra?
Which isotope of carbon is most abundant, based on mass spectra?
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$^{12}$C. The most abundant carbon isotope in nature.
$^{12}$C. The most abundant carbon isotope in nature.
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What does a peak at m/z = 16 indicate in an oxygen mass spectrum?
What does a peak at m/z = 16 indicate in an oxygen mass spectrum?
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$^{16}$O isotope. The most abundant oxygen isotope with mass 16 amu.
$^{16}$O isotope. The most abundant oxygen isotope with mass 16 amu.
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What can cause isotopic peaks to appear at higher m/z values?
What can cause isotopic peaks to appear at higher m/z values?
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Presence of heavier isotopes. Higher mass isotopes have greater m/z values.
Presence of heavier isotopes. Higher mass isotopes have greater m/z values.
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What is the significance of the largest peak in a mass spectrum?
What is the significance of the largest peak in a mass spectrum?
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It represents the most abundant isotope. The base peak shows which isotope has the highest natural abundance.
It represents the most abundant isotope. The base peak shows which isotope has the highest natural abundance.
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How does the mass spectrometer separate isotopes?
How does the mass spectrometer separate isotopes?
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By deflecting ions based on mass-to-charge ratio. Magnetic field deflects ions differently based on their m/z ratio.
By deflecting ions based on mass-to-charge ratio. Magnetic field deflects ions differently based on their m/z ratio.
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