CH3 PART 2

Question 2

What is molecular mass?

Answer 2

The mass of a molecule calculated as the sum of the atomic masses of its constituent atoms.

Question 3

How is molecular mass typically measured?

Answer 3

It is measured in atomic mass units (amu) or grams per mole (g/mol).

Question 4

True or False: The molecular mass of water (H2O) is approximately 18 g/mol.

Answer 4

True

Question 5

What is the formula for calculating percent composition?

Answer 5

Percent composition = (mass of element in formula / molar mass of compound) x 100%

Question 6

What does a mass spectrometer do?

Answer 6

It measures the mass-to-charge ratio of ions to identify and quantify substances.

Question 7

Fill in the blank: The molecular mass of carbon dioxide (CO2) is _____ g/mol.

Answer 7

44

Question 8

What is the purpose of the ionization process in a mass spectrometer?

Answer 8

To convert molecules into ions for analysis.

Question 9

Multiple Choice: Which of the following is a step in mass spectrometry? A) Ionization B) Fragmentation C) Detection D) All of the above

Answer 9

D) All of the above

Question 10

What is percent composition of a compound?

Answer 10

The percentage by mass of each element in a compound.

Question 11

True or False: The empirical formula can provide percent composition.

Answer 11

True

Question 12

What is the empirical formula of a compound?

Answer 12

The simplest whole-number ratio of atoms of each element in the compound.

Question 13

Fill in the blank: The molecular mass of glucose (C6H12O6) is _____ g/mol.

Answer 13

180

Question 14

What is the role of the detector in a mass spectrometer?

Answer 14

To measure the abundance of ions and produce a mass spectrum.

Question 15

Multiple Choice: Which element has a molecular mass of approximately 1 g/mol? A) Oxygen B) Hydrogen C) Carbon D) Nitrogen

Answer 15

B) Hydrogen

Question 16

True or False: Mass spectrometry can only be used for organic compounds.

Answer 16

False

Question 17

What is the significance of the base peak in a mass spectrum?

Answer 17

It represents the most abundant ion in the sample.

Question 18

What is the molecular mass of sodium chloride (NaCl)?

Answer 18

58.44 g/mol

Question 19

Fill in the blank: The mass spectrometer uses _____ to separate ions based on their mass-to-charge ratio.

Answer 19

electric and magnetic fields

Question 20

What is the formula to determine the molecular mass of a compound from its percent composition?

Answer 20

Molecular mass = (mass of element in formula / percent composition) x 100%

Question 21

True or False: The molecular mass of a compound is always a whole number.

Answer 21

False

Question 22

What is the molecular mass of ammonia (NH3)?

Answer 22

17 g/mol

Question 23

Fill in the blank: The molecular mass of sulfuric acid (H2SO4) is _____ g/mol.

Answer 23

98

Question 24

Multiple Choice: Which of the following compounds has the highest molecular mass? A) Methane (CH4) B) Ethanol (C2H5OH) C) Propane (C3H8) D) Butane (C4H10)

Answer 24

D) Butane (C4H10)

Question 25

What is the mass spectrum?

Answer 25

A graphical representation of the mass-to-charge ratios of ions.

Question 26

What does the term 'isotope' refer to?

Answer 26

Atoms of the same element with different numbers of neutrons.

Question 27

True or False: Isotopes of an element have the same atomic mass.

Answer 27

False

Question 28

What is the molecular mass of calcium carbonate (CaCO3)?

Answer 28

100.09 g/mol

Question 29

Fill in the blank: The molecular mass of acetone (C3H6O) is _____ g/mol.

Answer 29

58

Question 30

What is the purpose of a calibration curve in mass spectrometry?

Answer 30

To relate the detector response to the concentration of analytes.

Question 31

Multiple Choice: Which type of mass spectrometry is used for large biomolecules? A) ESI B) MALDI C) Both A and B D) None of the above

Answer 31

C) Both A and B

Question 32

What is the molecular mass of ethanol (C2H5OH)?

Answer 32

46.07 g/mol

Question 33

True or False: The molecular mass can be determined using the periodic table.

Answer 33

True

Question 34

What is a common use of mass spectrometry in biochemistry?

Answer 34

To analyze proteins and metabolites.