Multiple Choice
Morphine has the molecular formula C17H19NO3. What is the mass percentage of carbon (C) in morphine? Provide your answer to two decimal places.
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3. Chemical Reactions
Mass Percent
Multiple Choice
Which of the following best describes the molecular ion formed in a mass spectrometer for a given molecule?
A
It is the molecule with one neutron removed, represented as M^-.
B
It is the molecule with one proton added, represented as MH^+.
C
It is the molecule with all electrons removed, represented as M^{2+}.
D
It is the molecule with one electron removed, represented as M^+.
Verified step by step guidance1
Understand that in mass spectrometry, the molecular ion is formed by the removal of one electron from the neutral molecule, resulting in a positively charged ion.
Recognize that removing one neutron does not create a charged species; neutrons are neutral particles and their removal changes the isotope, not the charge.
Know that adding a proton (H^+) to the molecule forms a protonated molecule, often seen in some ionization methods, but this is not the molecular ion itself.
Realize that removing all electrons to form M^{2+} is possible but less common; the typical molecular ion has a single positive charge due to the loss of one electron.
Therefore, the molecular ion is best described as the molecule with one electron removed, represented as M^+, which is the species detected in the mass spectrometer.
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