Charges of ions in a mass spectrometer

In summary, the charge of 126C ions in a mass spectrometer can be calculated using the formula q=mv/rB, where m is the mass of the ion, v is its speed, r is the radius of deflection, and B is the magnetic field strength. In this case, the charge was found to be 2e, or 3.2*10^-19 C. There may have been a discrepancy in the original question regarding the mass of the ion, as it is typically 12 atomic units, but the solution used a value of 14 atomic units.
  • #1
Karagoz
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Homework Statement


In a mass spectrometer, a few 126C ions are deflected with a radius of 12.9 cm. The ions have a speed of 5.67*10^4 m/s when they enter the field. The magnetic field has a strength of 3.2*10^-2 T. The charge of these ions must be ...

SOLUTION:
We use the formula: i F=qvB = mv2/r and find q.

q= mv / rB = (14*1,66·10^-27 kg * 5,67*10^4 m/s) / (0,129m * 3,2*10^-2 T) = 3,2*10^-19 C = 2e

Homework Equations



One atomic unit is 1,66*10^-27 kg

But isn't the mass of 126C atom is ca 1.99264654*10^-26 kg, which is ca 12 atomic units? ( https://www.britannica.com/science/atomic-mass )

Where does the 14 come from in the solution?

The Attempt at a Solution

 
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  • #2
Perhaps the question was modified from Nitrogen atoms to Carbon atoms at some point but the solution was not updated to reflect this?
 
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FAQ: Charges of ions in a mass spectrometer

What is a mass spectrometer?

A mass spectrometer is a scientific instrument that measures the mass and relative abundance of ions in a substance. It ionizes a sample and separates the ions based on their mass-to-charge ratio.

How are ions charged in a mass spectrometer?

Ions are charged in a mass spectrometer through a process called ionization. This can be done through various methods such as electron impact, electrospray, or matrix-assisted laser desorption/ionization (MALDI).

Why are ions charged in a mass spectrometer?

Ions are charged in a mass spectrometer to make them easier to manipulate and analyze. Charged particles can be accelerated, deflected, and detected using electric and magnetic fields, allowing for precise measurements of their mass.

How are the charges of ions determined in a mass spectrometer?

The charges of ions in a mass spectrometer are determined by measuring their mass-to-charge ratio (m/z). This is done by accelerating the ions through an electric field and measuring the amount of deflection caused by a perpendicular magnetic field.

What is the significance of ion charges in a mass spectrometer?

The charges of ions in a mass spectrometer are significant because they affect the path and speed of the ions as they pass through the instrument. This allows for accurate mass measurements and identification of the ions present in a sample.

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