RELATIVE MASS & ISOTOPE

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 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

Find Molecular Mass: Calculate the mass of one mole of CO₂ (carbon dioxide).

• 18.0 grams

• 44.0 grams

• 14.0 grams

• 180.0 grams

Find Atomic Mass: What is the mass of one mole of Lithium (Li)?

• 6.9 grams

• 14.0 grams

• 22.9 grams

• 56.9 grams

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

Isotopes of an element have a different number of...

• Protons

• Neutrons

• Electrons

• Mass

Tags

NGSS.HS-PS1-8

There are two primary isotopes found in any sample of copper: copper-63 and copper-65. The isotope ⁶⁵Cu composes 69.2% of the sample and ⁶³Cu comprises the other 30.8%. Based on this data, what is the atomic mass of copper?

• 29 amu

• 63.546 amu

• 64.4 amu

• 63.6 amu

Tags

NGSS.MS-PS1-1