Mass Spectrometry Quiz

What is the main purpose of mass spectrometry?

• To measure temperature

• To identify isotopes and molecules

• To create new elements

• To generate electricity

Answer explanation

The main purpose of mass spectrometry is to identify isotopes and molecules by measuring the mass-to-charge ratio of ions, allowing for detailed analysis of chemical compositions.

In mass spectrometry, what happens to atoms or molecules before they enter the machine?

• They are frozen

• They are heated

• They are ionized (given an electric charge)

• They are mixed with water

Answer explanation

In mass spectrometry, atoms or molecules are ionized (given an electric charge) before entering the machine. This ionization is crucial for their detection and analysis, making it the correct choice.

What force is used to separate ions in a mass spectrometer?

• Gravity

• Magnetic or electric fields

• Wind

• Sound waves

Answer explanation

In a mass spectrometer, ions are separated using magnetic or electric fields. These fields influence the trajectory of charged particles, allowing for their differentiation based on mass-to-charge ratios.

Why do lighter ions move differently than heavier ions in a mass spectrometer?

• They are a different color

• They have less mass and accelerate more

• They are attracted to light

• They are colder

Answer explanation

Lighter ions have less mass, allowing them to accelerate more quickly in a mass spectrometer. This difference in acceleration leads to distinct movement patterns compared to heavier ions, making the correct choice 'They have less mass and accelerate more'.

What does the detector in a mass spectrometer measure?

• The color of ions

• The temperature of ions

• The arrival time or path of ions

• The sound of ions

Answer explanation

The detector in a mass spectrometer measures the arrival time or path of ions as they reach it. This information is crucial for determining the mass-to-charge ratio of the ions, which is essential for mass analysis.

Mass spectrometry can only be used for atoms, not molecules.

• True

• False

Answer explanation

The statement is false because mass spectrometry can analyze both atoms and molecules. It is widely used to determine the mass and structure of various molecular species.

Heavier ions curve more than lighter ions in a magnetic field.

• True

• False

Answer explanation

In a magnetic field, the curvature of ions is inversely related to their mass. Heavier ions experience less curvature than lighter ions due to their greater inertia. Therefore, the statement is false.

A mass spectrum shows the mass and abundance of different ions.

• True

• False

Answer explanation

A mass spectrum indeed displays the mass and abundance of various ions, making the statement true. It provides crucial information for identifying and quantifying different substances.

What is an isotope?

Answer explanation

An isotope is a variant of a chemical element that has the same number of protons but a different number of neutrons, resulting in a different atomic mass. For example, carbon-12 and carbon-14 are isotopes of carbon.

Name two ways that atoms or molecules can be ionized in mass spectrometry.

Answer explanation

Atoms or molecules can be ionized in mass spectrometry by electron impact (EI), where high-energy electrons knock out electrons from the sample, or by chemical ionization (CI), where a reagent gas ionizes the sample through proton transfer.