Question 1

What is the horizontal axis of a mass spectrum?

Accepted Answer

The horizontal axis of a mass spectrum represents mass/charge (m/z), which is the ratio of the mass of an ion divided by its charge. This allows for comparison of ions with different charges and identification of the molecular weight of a compound.

Question 2

The amount of energy in infrared light corresponds to:

Accepted Answer

Infrared light is absorbed by organic molecules and causes an increase in certain molecular motions, such as bond vibrations. This corresponds to the amount of energy needed to increase these motions, which is option D.

Question 3

The amount of energy in electromagnetic radiation is related to the frequency and wavelength of the radiation. High energy radiation, like gamma rays, is of:

Accepted Answer

The energy of electromagnetic radiation is directly proportional to its frequency. Therefore, high energy radiation will have high frequency. In addition, the wavelength and frequency of electromagnetic radiation are inversely proportional. Therefore, high frequency radiation will have short wavelength. Choice C is the only option that satisfies both requirements for high energy radiation - high frequency and short wavelength.

Question 4

Which of the following regions in the electromagnetic spectrum corresponds to the radiation with the highest energy?

Accepted Answer

Ultraviolet radiation has a higher energy than radio waves, infrared, and visible light. This is because ultraviolet radiation has a shorter wavelength, which is inversely proportional to the energy of a photon according to the equation E=hc/λ, where E is energy, h is Planck's constant, c is the speed of light, and λ is wavelength.

Question 5

Which of the following compounds gives an infrared spectrum with a peak at strong 1730 cm−¹?

Accepted Answer

The peak at 1730 cm-1 is a characteristic absorption peak for carbonyl groups (C=O) in organic compounds. Compound B contains a carbonyl group in its structure, specifically a ketone group, which is responsible for this peak in its infrared spectrum. The other compounds do not contain any functional groups that would give rise to a peak at 1730 cm-1 in their infrared spectra.

Question 6

Which of the following bonds undergoes stretching at the highest frequency?

Accepted Answer

The bond that undergoes stretching at the highest frequency is the C=O bond, as it has a higher force constant and lower bond length compared to the other options.

Question 7

Which of the following compounds gives an infrared spectrum with no significant peaks at ˜3300 cm−¹ or 1600−1680 cm−¹?

Accepted Answer

The answer of Which of the following compounds gives an...

Question 8

Which of the following bonds undergoes stretching at the highest frequency?

Accepted Answer

The answer of Which of the following bonds undergoes stretching...

Question 9

Which of the following statements best describes the base peak in a mass spectrum?

Accepted Answer

The base peak in a mass spectrum is the peak of highest intensity. This means that it represents the most abundant ion in the sample being analyzed.

Question 10

Which of the following does not involve the interaction of molecules with electromagnetic energy?

Accepted Answer

Mass spectrometry does not use electromagnetic radiation to study molecules. It instead uses electric and magnetic fields to measure the mass-to-charge ratio of ionized molecules. Infrared, ultraviolet, and nuclear magnetic resonance spectroscopy all rely on the absorption or emission of electromagnetic radiation by molecules.

Question 11

What are the units for electromagnetic radiation used in infrared spectroscopy?

Accepted Answer

Infrared spectroscopy typically uses wavenumbers for the units of electromagnetic radiation, which are expressed in inverse centimeters (cm⁻¹). This unit is used to denote the number of wave cycles per centimeter and is a standard in the field for reporting vibrational frequencies.

Question 12

Which of the following compounds gives an infrared spectrum with peaks at 3300 cm−¹ (sharp peak) and 2150 cm−¹ (sharp peak)?

Accepted Answer

The answer of Which of the following compounds gives an...

Question 13

Select the most reasonable formula for the compounds with the following mass spectral data. -Refer to instructions. M⁺ at m/z = 101

Accepted Answer

The mass spectral data contains peaks at m/z = 101, indicating that the molecular formula contains an odd number of nitrogen atoms. Option C is the only answer choice with an odd number of nitrogen atoms (1) and also includes all the necessary elements (C, H, S).

Question 14

Which of the following compounds gives an infrared spectrum with a peak at ˜1750 cm−¹, but no significant peaks at 3000−3500 cm−¹ or 1050−1250 cm−¹?

Accepted Answer

The answer of Which of the following compounds gives an...

Question 15

Which of the following compounds gives an infrared spectrum with peaks at 3300 cm−¹ (strong, broad peak) and 1640 cm−¹ (sharp, weak peak)?

Accepted Answer

The answer of Which of the following compounds gives an...

Question 16

What is the vertical axis of a mass spectrum?

Accepted Answer

The vertical axis of a mass spectrum represents the abundance or intensity of ions detected, indicating how many ions of each mass-to-charge ratio are present.

Question 17

Examining the infrared spectrum of a compound allows us to:

Accepted Answer

The infrared spectrum of a compound provides information about the functional groups present and their chemical environment, which allows us to identify the compound's chemical structure.

Question 18

Which of the following bonds gives rise to a strong absorbance near 1700 cm−¹ in the infrared spectrum?

Accepted Answer

The bond that gives rise to a strong absorbance near 1700 cm−1 is the C=O bond, also known as the carbonyl group. This is a characteristic absorption for carbonyl-containing functional groups, such as aldehydes, ketones, carboxylic acids, and esters.

Question 19

Refer to instructions. M⁺ at m/z = 216

Accepted Answer

From the given information, we can deduce that the molecule has a molecular weight of 216. Option B has a series of sulfur (S) and bromine (Br) atoms that add up to a total molecular weight of 216, which matches the given information. Therefore, option B is the best choice. Option A has an extra chlorine (Cl) atom which would increase the molecular weight to 252, option C has too high of a molecular weight (226), and option D does not have enough atoms to reach a molecular weight of 216.

Question 20

Which of the following compounds gives an infrared spectrum with peaks at 3000−3500 cm−¹ and ˜1750 cm−¹?

Accepted Answer

The answer of Which of the following compounds gives an...

Quiz 10: Structure Determination: Mass Spectrometry, Infrared Spectroscopy, and Ultraviolet Spectroscopy

What is the horizontal axis of a mass spectrum?

The amount of energy in infrared light corresponds to:

The amount of energy in electromagnetic radiation is related to the frequency and wavelength of the radiation. High energy radiation, like gamma rays, is of:

Which of the following regions in the electromagnetic spectrum corresponds to the radiation with the highest energy?

Which of the following compounds gives an infrared spectrum with a peak at strong 1730 cm−¹?

Which of the following bonds undergoes stretching at the highest frequency?

Which of the following compounds gives an infrared spectrum with no significant peaks at ˜3300 cm−¹ or 1600−1680 cm−¹?

Which of the following bonds undergoes stretching at the highest frequency?

Which of the following statements best describes the base peak in a mass spectrum?

Which of the following does not involve the interaction of molecules with electromagnetic energy?

What are the units for electromagnetic radiation used in infrared spectroscopy?

Which of the following compounds gives an infrared spectrum with peaks at 3300 cm−¹ (sharp peak) and 2150 cm−¹ (sharp peak) ?

Select the most reasonable formula for the compounds with the following mass spectral data. -Refer to instructions. M⁺ at m/z = 101

Which of the following compounds gives an infrared spectrum with a peak at ˜1750 cm−¹, but no significant peaks at 3000−3500 cm−¹ or 1050−1250 cm−¹?

Which of the following compounds gives an infrared spectrum with peaks at 3300 cm−¹ (strong, broad peak) and 1640 cm−¹ (sharp, weak peak) ?

What is the vertical axis of a mass spectrum?

Examining the infrared spectrum of a compound allows us to:

Which of the following bonds gives rise to a strong absorbance near 1700 cm−¹ in the infrared spectrum?

Refer to instructions. M⁺ at m/z = 216

Which of the following compounds gives an infrared spectrum with peaks at 3000−3500 cm−¹ and ˜1750 cm−¹?

Quiz 10: Structure Determination: Mass Spectrometry, Infrared Spectroscopy, and Ultraviolet Spectroscopy

What is the horizontal axis of a mass spectrum?

The amount of energy in infrared light corresponds to:

The amount of energy in electromagnetic radiation is related to the frequency and wavelength of the radiation. High energy radiation, like gamma rays, is of:

Which of the following regions in the electromagnetic spectrum corresponds to the radiation with the highest energy?

Which of the following compounds gives an infrared spectrum with a peak at strong 1730 cm−1?

Which of the following bonds undergoes stretching at the highest frequency?

Which of the following compounds gives an infrared spectrum with no significant peaks at ˜3300 cm−1 or 1600−1680 cm−1?

Which of the following bonds undergoes stretching at the highest frequency?

Which of the following statements best describes the base peak in a mass spectrum?

Which of the following does not involve the interaction of molecules with electromagnetic energy?

What are the units for electromagnetic radiation used in infrared spectroscopy?

Which of the following compounds gives an infrared spectrum with peaks at 3300 cm−1 (sharp peak) and 2150 cm−1 (sharp peak) ?

Select the most reasonable formula for the compounds with the following mass spectral data. -Refer to instructions. M+ at m/z = 101

Which of the following compounds gives an infrared spectrum with a peak at ˜1750 cm−1, but no significant peaks at 3000−3500 cm−1 or 1050−1250 cm−1?

Which of the following compounds gives an infrared spectrum with peaks at 3300 cm−1 (strong, broad peak) and 1640 cm−1 (sharp, weak peak) ?

What is the vertical axis of a mass spectrum?

Examining the infrared spectrum of a compound allows us to:

Which of the following bonds gives rise to a strong absorbance near 1700 cm−1 in the infrared spectrum?

Refer to instructions. M+ at m/z = 216

Which of the following compounds gives an infrared spectrum with peaks at 3000−3500 cm−1 and ˜1750 cm−1?

Which of the following compounds gives an infrared spectrum with a peak at strong 1730 cm−¹?

Which of the following compounds gives an infrared spectrum with no significant peaks at ˜3300 cm−¹ or 1600−1680 cm−¹?

Which of the following compounds gives an infrared spectrum with peaks at 3300 cm−¹ (sharp peak) and 2150 cm−¹ (sharp peak) ?

Select the most reasonable formula for the compounds with the following mass spectral data. -Refer to instructions. M⁺ at m/z = 101

Which of the following compounds gives an infrared spectrum with a peak at ˜1750 cm−¹, but no significant peaks at 3000−3500 cm−¹ or 1050−1250 cm−¹?

Which of the following compounds gives an infrared spectrum with peaks at 3300 cm−¹ (strong, broad peak) and 1640 cm−¹ (sharp, weak peak) ?

Which of the following bonds gives rise to a strong absorbance near 1700 cm−¹ in the infrared spectrum?

Refer to instructions. M⁺ at m/z = 216

Which of the following compounds gives an infrared spectrum with peaks at 3000−3500 cm−¹ and ˜1750 cm−¹?