2:Atoms, Molecules And Stoichiometry Flashcards
What is an isotope
Isotopes are atoms which have the same number of protons but different numbers of neutrons
Why do isotopes have almost identical chemical properties
Because chemical properties are largely determined by the arrangement of electrons and protons so the number of neutrons does not affect this.
Definition of relative isotopic mass
The relative isotopic mass of an isotope is the mass of an atom of the isotope compared with 1/12 of the mass of an atom of ¹²C
Definition of relative atomic mass
The relative atomic mass (Ar) of an element is the weighted mean mass of an atom of an element compared with 1/12 an atom of ¹²C
How does mass spectrometry work
It converts an atom or molecule into a positive ion by removing electron(s) and then measuring how the motion of the ion is perturbed by an electric or magnetic field.
Definition of relative formula mass (Mr)
The relative formula mass (Mr) of a substance is the average mass of a formula unit of that substance compared to 1/12 of the mass of an atom of ¹²C.
What is Avagrado’s constant
6.02 x 10²³
Definition of Molar Mass
The mass (in g) of 1 mole of a substance. The units of molar mass are g mol¯¹
How to calculate mol
mol =mass / Mr
How to calculate number of particles
No. particles = mol x Avagadro’s number
