Mass Spectrometry and Molecular Weights

The video tutorial from Chem Help ASAP explains the concept of 'mass' in mass spectrometry, focusing on how different isotopes affect the interpretation of a mass spectrum. It covers the calculation of m/z values, the significance of nominal mass, and provides examples using water, glucose, and nicotine. The tutorial highlights the unique isotope patterns of chlorine and bromine, emphasizing the M:M+2 peak pattern. The video concludes by summarizing the importance of nominal mass and isotope patterns in mass spectrometry.

What does the 'm' in m/z values represent in mass spectrometry?

• The volume of the ion

• The speed of the ion

• The mass of the ion

• The charge of the ion

How is the nominal mass of a molecule determined?

• By measuring the speed of the ion

• By calculating the charge of the ion

• By summing the atomic masses of the most common isotopes

• By averaging the atomic masses of all isotopes

What is the molecular weight of water?

• 36.000 g/mol

• 180.156 g/mol

• 162.236 g/mol

• 18.015 g/mol

What is the nominal mass of glucose?

• 162 Da

• 180 Da

• 18 Da

• 36 Da

What is the nominal mass of nicotine?

• 36 Da

• 18 Da

• 162 Da

• 180 Da

Which element has a characteristic M:M+2 pattern with a 3:1 ratio in mass spectrometry?

• Oxygen

• Carbon

• Chlorine

• Hydrogen

What is the nominal mass of the parent ion for H-Cl?

• 80 Da

• 18 Da

• 38 Da

• 36 Da

What is the ratio of the M and M+2 peaks for bromine in mass spectrometry?

• 3:1

• 1:1

• 2:1

• 4:1

Which isotope of chlorine is more abundant?

• 35Cl

• 79Br

• 37Cl

• 81Br

Which element has isotopes with almost equal abundance, leading to a 1:1 M:M+2 peak ratio?

• Carbon

• Oxygen

• Bromine

• Chlorine