Massspectrometry is more often applied to molecules than to atoms. We will see in Chapter 3 that the molecular weight of a molecule is the sum of the atomic weights of the atoms in the molecule. The mass spectrum of H 2 is taken under conditions that prevent decomposition into H atoms. The two naturally occurring isotopes of hydrogen are 1 H (atomic mass = 1.00783 amu; abundance 99.9885%) and 2 H (atomic mass = 2.01410; abundance 0.0115%). (a) How many peaks will the mass spectrum have?

Hi everyone here, we have a question telling us, mass spectrometry can reveal the presence of isotopes of an element in a compound being analyzed. Isotopes as separate peaks can most easily be seen next to the molecular ion peak chlorine has two isotopes, chlorine 35 abundant, 76% and chlorine 37 abundance 24%. If chloral, methane, ch three cl is subjected to mass spectrometry, how many molecular ion peaks with the mass spectrum have? So carbon and chlorine. Both have two stable isotopes each. So when they come together they will form four peaks. So we have the molar mass of korean 12 Or of carbon And Chlorine 35 Is 50 g per mole. So we will have a peak at 50. We will have a peak at 52 Due to carbon 12 And cool rain 37. We will have a peak at 51 Due to Carbon 13 and Chlorine 35. And we will have a peak at 53 Due to Carbon 13 and Chlorine 37. So, these are our peaks. Thank you for watching. Bye.

Ch.2 - Atoms, Molecules, and Ions

All textbooks

Brown 14th Edition

Ch.2 - Atoms, Molecules, and Ions

Problem 40a

Chapter 2, Problem 40a

Massspectrometry is more often applied to molecules than to atoms. We will see in Chapter 3 that the molecular weight of a molecule is the sum of the atomic weights of the atoms in the molecule. The mass spectrum of H₂ is taken under conditions that prevent decomposition into H atoms. The two naturally occurring isotopes of hydrogen are ¹H (atomic mass = 1.00783 amu; abundance 99.9885%) and ²H (atomic mass = 2.01410; abundance 0.0115%). (a) How many peaks will the mass spectrum have?

Verified step by step guidance

Step 1: Understand the problem. The problem is asking how many peaks will be seen in the mass spectrum of H2. The mass spectrum is a graph showing the mass-to-charge ratio on the x-axis and the relative abundance on the y-axis. Each peak in the spectrum represents a different isotope of the element.

Step 2: Identify the isotopes of hydrogen. The problem states that there are two naturally occurring isotopes of hydrogen: 1H and 2H.

Step 3: Consider the possible combinations of these isotopes in a H2 molecule. The H2 molecule could consist of two 1H atoms, two 2H atoms, or one of each.

Step 4: Each different combination of isotopes will result in a different mass for the H2 molecule, and therefore a different peak in the mass spectrum.

Step 5: Therefore, the mass spectrum of H2 will have three peaks, one for each possible combination of isotopes: 1H-1H, 1H-2H, and 2H-2H.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Mass Spectrometry

Mass spectrometry is an analytical technique used to measure the mass-to-charge ratio of ions. It provides information about the molecular weight and structure of compounds by generating a mass spectrum, which displays the abundance of ions at different mass-to-charge ratios. In the context of molecules, it helps identify the presence of different isotopes and molecular fragments.

Isotopes

Isotopes are variants of a chemical element that have the same number of protons but different numbers of neutrons, resulting in different atomic masses. For hydrogen, the two isotopes are protium (¹H) and deuterium (²H). The presence of isotopes in a sample affects the mass spectrum, as each isotope will produce a distinct peak corresponding to its mass.

Mass Spectrum Peaks

In a mass spectrum, each peak represents a different ion detected by the mass spectrometer, corresponding to specific mass-to-charge ratios. The number of peaks is influenced by the isotopes present in the sample and their relative abundances. For the hydrogen molecule (H₂), the mass spectrum will show peaks for both isotopes, indicating the molecular composition and the presence of H₂ and its isotopic variants.

Recommended video:

Guided course

02:53

Electromagnetic Spectrum

Related Practice

Textbook Question

Consider the mass spectrometer shown in Figure 2.11. Determine whether each of the following statements is true or false. If false, correct the statement to make it true: (a) The paths of neutral (uncharged) atoms are not affected by the magnet.

Textbook Question

Consider the mass spectrometer shown in Figure 2.11. Determine whether each of the following statements is true or false. If false, correct the statement to make it true: (b) The height of each peak in the mass spectrum is inversely proportional to the mass of that isotope.

views

Textbook Question

Massspectrometry is more often applied to molecules than to atoms. We will see in Chapter 3 that the molecular weight of a molecule is the sum of the atomic weights of the atoms in the molecule. The mass spectrum of H₂ is taken under conditions that prevent decomposition into H atoms. The two naturally occurring isotopes of hydrogen are ¹H (atomic mass = 1.00783 amu; abundance 99.9885%) and ²H (atomic mass = 2.01410; abundance 0.0115%). (c) Which peak will be the largest, and which the smallest?

Textbook Question

For each of the following elements, write its chemical symbol, locate it in the periodic table, give its atomic number, and indicate whether it is a metal, metalloid, or nonmetal: (a) radon (b) tellurium (c) cadmium (d) chromium (e) barium (f) selenium (g) arsenic.