Chapter 6 - Quantifying atoms and compounds Flashcards
Isotope
atoms of the same element that have a different mass due to a different number of neutrons
Mass spectrometry
analytical technique used to measure the mass of ions relative to their charge
Mass–to–charge ratio (m/z)
the mass of an ion divided by its charge
Molecular formula
actual number of atoms in a molecule
Relative abundance
percentage of a particular isotope found in a naturally occurring sample of an element
Relative atomic mass (Ar)
weighted average of the masses of an element’s isotopes on a scale on which a carbon-12 atom is assigned a value of 12 exactly
Relative formula mass (Mr)
weighted average of a substance’s masses of the formula units on a scale on which the mass of a carbon-12 atom is assigned a value of 12 exactly
Relative isotopic mass
the mass of the isotope on the scale in which the relative isotopic mass of the carbon-12 atom is assigned a value of 12 exactly
Relative molecular mass (Mr)
weighted average of a molecule’s masses of the formula units on a scale on which the mass of a carbon-12 atom is assigned a value of 12 exactly
Avogadro’s constant (NA)
the number of atoms in exactly 12 g of 12C, 6.02 × 1023 mol−1
Entities
atoms, molecules, compounds, ions, electrons etc.
Molar mass (M)
the mass, in grams, per mol of substance (g mol−1)
Mole (n)
amount of substance, in mol
Empirical formula
chemical formula depicting the lowest whole number ratio of atoms of different elements in a compound
Molecular formula
actual number of atoms in a molecule
