AP Chemistry Flashcards: Mass Spectra Of Elements

What this deck covers

This deck focuses on Mass Spectra Of Elements, giving you a quick way to review the definitions, rules, and examples that matter most for AP Chemistry.

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Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: Find the relative atomic mass given isotopic masses and abundances.

Answer: Calculate using $\text{RAM} = \frac{\text{sum of (m/z) × abundance}}{\text{total abundance}}$. Weighted average formula using isotopic masses and abundances.

Flashcard 2: What is the role of acceleration in mass spectrometry?

Answer: To give ions kinetic energy. Accelerated ions can be deflected by magnetic fields.

Flashcard 3: What information does a mass spectrum provide about an element?

Answer: Isotopic composition and abundance. Shows which isotopes exist and their relative amounts.

Flashcard 4: What is the purpose of the vacuum in a mass spectrometer?

Answer: To prevent collisions with air molecules. Ensures unobstructed ion path to the detector.

Flashcard 5: How is the molecular ion peak identified in a mass spectrum?

Answer: It is the peak with the highest m/z value. The rightmost peak shows the intact molecule's mass.

Flashcard 6: What is the significance of the largest peak in a mass spectrum?

Answer: It represents the most abundant isotope. The base peak shows which isotope has the highest natural abundance.

Flashcard 7: Determine the presence of sulfur isotopes in a mass spectrum.

Answer: Look for peaks at m/z = 32, 33, 34. Sulfur has isotopes $^{32}$S, $^{33}$S, and $^{34}$S.

Flashcard 8: Identify the ionization method used in mass spectrometry.

Answer: Electron impact ionization. High-energy electrons remove electrons from atoms/molecules.

Flashcard 9: What can cause broad peaks in a mass spectrum?

Answer: Instrumental resolution limitations. Poor resolution cannot separate closely spaced m/z values.

Flashcard 10: Determine the isotopic composition of chlorine using its mass spectrum.

Answer: Peaks at m/z = 35 and 37. Shows $^{35}$Cl and $^{37}$Cl isotopes in 3:1 ratio.

Flashcard 11: Identify the purpose of a mass spectrometer.

Answer: To measure the masses of isotopes and their abundances. Determines isotopic composition and relative abundances of elements.

Flashcard 12: What is the significance of a mass spectrum peak at m/z = 18?

Answer: Could indicate water or a fragment ion. Could be H₂O⁺ molecular ion or larger molecule fragment.

Flashcard 13: How can isotopic ratios be determined from a mass spectrum?

Answer: By comparing relative peak heights. Peak height ratios show isotopic abundance ratios.

Flashcard 14: What does the x-axis represent in a mass spectrum?

Answer: Mass-to-charge ratio (m/z). Shows the mass divided by charge for each ion detected.

Flashcard 15: What is the function of the magnetic field in a mass spectrometer?

Answer: To deflect ions based on m/z. Creates force that separates ions by mass-to-charge ratio.

Flashcard 16: What does a low abundance peak in a mass spectrum indicate?

Answer: Less common isotope or fragment. Shows minor isotope or molecular fragmentation product.

Flashcard 17: What does a cluster of peaks in a mass spectrum suggest?

Answer: Presence of isotopic variants. Multiple isotopes create pattern of related peaks.

Flashcard 18: How are ions detected in a mass spectrometer?

Answer: By measuring their abundance as electrical signals. Ion collisions create electrical current proportional to abundance.

Flashcard 19: What is the typical charge state observed in a mass spectrum?

Answer: +1. Most ions have single positive charge from electron loss.

Flashcard 20: What is the unit for mass-to-charge ratio in mass spectrometry?

Answer: Atomic mass units per charge (amu/e). Standard unit expressing mass per unit charge.

Flashcard 21: Which element's isotopes can be separated using mass spectrometry?

Answer: Any element with isotopes. Mass spectrometry can separate isotopes of all elements.

Flashcard 22: What does a peak at m/z = 16 indicate in an oxygen mass spectrum?

Answer: $^{16}$O isotope. The most abundant oxygen isotope with mass 16 amu.

Flashcard 23: Identify the peak corresponding to the molecular ion of methane (CH₄).

Answer: Peak at m/z = 16. Methane molecular ion has mass 16 amu.

Flashcard 24: What can cause isotopic peaks to appear at higher m/z values?

Answer: Presence of heavier isotopes. Higher mass isotopes have greater m/z values.

Flashcard 25: Which isotope of carbon is most abundant, based on mass spectra?

Answer: $^{12}$C. The most abundant carbon isotope in nature.

Flashcard 26: What does the y-axis represent in a mass spectrum?

Answer: Relative abundance. Shows how much of each ion is present relative to the most abundant.

Flashcard 27: How is the resolution of a mass spectrometer defined?

Answer: Ability to distinguish between close m/z values. Measures ability to separate peaks with similar m/z values.

Flashcard 28: How does the mass spectrometer separate isotopes?

Answer: By deflecting ions based on mass-to-charge ratio. Magnetic field deflects ions differently based on their m/z ratio.

Flashcard 29: Describe the main stages of a mass spectrometer.

Answer: Ionization, acceleration, deflection, detection. Sequential steps that separate and detect ions by mass.

Flashcard 30: Calculate the average atomic mass given isotopic data.

Answer: Use $\text{Average mass} = \frac{\text{sum of (m/z) × abundance}}{\text{total abundance}}$. Weighted average calculation using isotopic data.

Flashcard 31: What does the term 'base peak' mean in mass spectrometry?

Answer: The tallest peak representing 100% relative abundance. The peak set to 100% for comparing other peak heights.

Flashcard 32: Which factor affects the degree of ion deflection in a mass spectrometer?

Answer: Mass-to-charge ratio (m/z). Determines how much ions deflect in the magnetic field.

Flashcard 33: State the basic principle of mass spectrometry.

Answer: Ions are separated based on their mass-to-charge ratio (m/z). Lighter ions deflect more than heavier ions in magnetic fields.

Flashcard 34: What is the charge of ions detected in a mass spectrometer?

Answer: Typically +1 charge. Single positive charge from electron removal during ionization.

Flashcard 35: What is the purpose of the detector in a mass spectrometer?

Answer: To measure the abundance of ions. Converts ion impacts into measurable electrical signals.

Flashcard 36: What is the effect of higher ion velocity in mass spectrometry?

Answer: Greater deflection. Faster ions deflect more in magnetic field.

Flashcard 37: How does a mass spectrometer identify different isotopes?

Answer: By their distinct m/z values. Each isotope has unique mass giving distinct m/z value.

Flashcard 38: What does a mass spectrum reveal about molecular ions?

Answer: Their mass and charge. Shows molecular weight and structural information.