Atom Counting and Molar 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

What is the relative atomic mass of sodium?

• 11
• 23
• 46
• 64

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

• 19
• 38
• 9
• 18

What is the unit of relative molecular mass?

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

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

• 32
• 64
• 81
• 94

Tags

NGSS.HS-PS1-7

Each element is defined by the number of

• Atoms

• Isotopes

• Neutrons

• Protons

• Nuclei.

What is the relative formula mass of ammonium nitrate, NH4NO3 ?

[Relative atomic mass: N, 14; H, 1; O, 16]

• 76

• 79

• 80

• 90

Calculate the relative formula mass of

aluminium sulphate, Al₂(SO₄)₃

[Relative atomic mass:

O = 16 ; Al = 27 ; S = 32 ; Cl = 35.5 ; Cu = 64 ]

The atomic mass of an element is the ___.

• average of the mass number and the atomic number for the element

• weighted average of the masses of the isotopes of the element

• total mass of the isotopes of the element

• total number of subatomic particles in the nucleus

What is the relative formula mass of NaOH?

• 20
• 39
• 40
• 45