Relative atomic mass and molecular mass

The relative atomic mass is the average mass of an atom compared to 

• the mass of a carbon-12 atom.
• 1/12 the mass of a carbon-12 atom
• the mass of a hydrogen atom
• 1/12 the mass of a hydrogen atom

The relative molecular mass of a compound is equal to the sum of its

• Atomic mass
• Atomic number
• Oxidation number
• Valence electrons

What is the relative atomic mass of sodium?

• 11

• 23

• 46

• 64

Tags

NGSS.HS-PS1-1

What is the relative molecular mass of fluorine gas, F₂?

• 19

• 38

• 9

• 18

Tags

NGSS.HS-PS1-1

What is the unit of relative molecular mass?

• kilogram
• gram
• gram per mole (g/mol)
• no units

The formula of a compound is X(OH)₂. Given that the M_r of the compound is 98, calculate the A_r of X.

• 32

• 64

• 81

• 94

An element has two naturally occurring isotopes. One is 10.013 amu and is 19.9% abundant. The other is 11.01 amu and is 80.1% abundant. What is the average atomic mass? What element is it?

• 9.012 Beryllium

• 12.011 Carbon

• 6.941 Lithium

• 10.812 Boron