Relative Atomic Mass and Molecular Weight

The video tutorial covers the concepts of particle size, relative atomic mass, and relative molecular mass. It explains the challenges in measuring molecular size and the importance of relative atomic mass in chemistry calculations. The tutorial details how to calculate relative atomic mass using atomic numbers and introduces the mass spectrometer as a tool for precise measurement. It also discusses isotopes and their impact on atomic mass. The video concludes with a focus on relative molecular mass, providing examples of calculations for compounds.

What is the typical size range of molecules or atoms?

• n times 10 to the power of 7 cm

• n times 10 to the power of -7 cm

• n times 10 to the power of -3 cm

• n times 10 to the power of 3 cm

What is another term for relative atomic mass?

• Molecular weight

• Mass number

• Atomic weight

• Molar mass

How is the relative atomic mass of an element generally related to its atomic number?

• It is half the atomic number

• It is approximately twice the atomic number

• It is equal to the atomic number

• It is three times the atomic number

What instrument is used to measure the relative atomic mass accurately?

• X-ray diffractometer

• Nuclear magnetic resonance

• Electron microscope

• Mass spectrometer

Why do elements have fractional atomic masses?

• Due to the presence of isotopes

• Because of neutron decay

• Because of measurement errors

• Due to electron mass variations

What is the reference point used in modern times for measuring atomic mass?

• Hydrogen

• Oxygen

• Carbon-12

• Nitrogen

How is the relative molecular mass of a compound determined?

• By dividing the atomic masses of all atoms

• By adding the relative atomic masses of all atoms

• By multiplying the atomic masses of all atoms

• By adding the atomic numbers of all atoms

What is the relative atomic mass of oxygen approximately?

• 14.99

• 15.00

• 16.00

• 15.99

Which element was initially used as a reference point for atomic mass?

• Carbon

• Hydrogen

• Nitrogen

• Oxygen

What is the relative molecular mass of calcium carbonate?

• 50

• 100

• 200

• 150