Atoms, moles and stoichiometry Flashcards
What is the definition of atomic mass unit?
The mass of a single atom is so small that it is impossible to weigh it directly. Atomic masses are therefore defined in terms of a standard atom which is called the unified atomic mass unit. This unified atomic mass is defined as one-twelfth of the mass of a carbon-12 isotope
What is the definition of relative atomic mass (Ar)?
The relative atomic mass (Ar) of an element is the ratio of the average mass of the atoms of an element to the unified atomic mass unit.
The relative atomic mass is determined by using the average mass of the isotopes of a particular element.
What are the units used for relative atomic mass (Ar)?
The Ar has no units as it is a ratio and the units cancel each other out.
What is the formula for calculating the relative atomic mass of an element?
relative atomic mass of element x= average mass of one atom of x divided by 1/12 of the mass of one carbon-12 atom.
What is the definition of relative isotopic mass?
The relative isotopic mass is the mass of a particular atom of an isotope compared to the value of the unified atomic mass unit.
How can relative isotopic mass be calculated?
