Relative masses of atoms & molecules

What is the definition of relative molecular mass?

• The mass of isotope relative to 1/12 of the mass of carbon-12

• The weighted average mass of formula relative to 1/12 of the mass of carbon-12

• The weighted average mass of molecule relative to 1/12 of the mass of carbon-12

• The weighted average mass of molecule relative to 1/12 of the mass of carbon-13

What definition does this belong to?
"The mass of isotope relative to 1/12 of the mass of carbon-12"

• Relative isotopic mass

• Relative atomic mass

• Relative molecular mass

• Atomic mass unit

Unified atomic mass unit has the definition of

• 1/12 of the mass of an atom of the carbon-12 isotope

• 1/2 of the mass of the molecular mass of hydrogen-2

• 1/16 of the atomic mass of oxygen-8

• 1/14 of the molecular mass of nitrogen-7

Calculate the relative formula mass of:

NaOH

• 40.0

• 35.5

• 23.0

• 41.5

By using the data, calculate the relative atomic mass of bromine to 3 significant-figures.

• 55.7

• 54.0

• 56.0

• 91.7

Which statement is correct?

• Cl has a relative isotopic mass of 35.5

• Cl₂ has a relative molecular mass of 70

• ICl has a relative molecular mass of 162.4

• NaCl has a relative molecular mass of 58.5

• 0.56

• 84

• 56

• 87.7