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Reading Two Atom Masses in One Peak 4 questions
Reading Two Atom Masses in One Peak
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A classroom detector reports the rounded mass of each particle. The model has two nitrogen isotopes of mass 14 u and 15 u. A nitrogen molecule has two N atoms, and its mass is the sum of their masses. The model also allows a one-atom silicon particle of mass 29 u.
| Record | Mass peaks detected (u) |
|---|---|
| Original sample | 28, 29, 30 |
| After all two-atom nitrogen molecules separate | 14, 15, 29 |
Question 1
Which nitrogen atom pair gives a molecule with mass 29 u?
- 14 u with 14 u
- 14 u with 15 u
- 15 u with 15 u
- No nitrogen pair can have that mass.
Question 2
A student says the original 29 u peak alone establishes that silicon is present. Explain why that peak cannot establish the particle identity by itself.
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Question 3
Use the second record to explain which evidence shows that at least some of the original particles were single silicon atoms.
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Question 4
Predict the second record for a sample containing the same nitrogen molecules but no silicon. Explain what changes and what stays.
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