2.1 - Atoms Ions And Compounds Flashcards
Isotope def
Isotopes are atoms of the same element with the same atomic number, but with a different number of neutrons, resulting in a different mass number
Relative atomic mass def
The weighted mean mass of an atom of an element, relative to one-twelfth of the mean mass of an atom of carbon-12
Relative isotopic mas
The isotopic mass of an isotope relative to one-twelfth of the mean mass of an atom of carbon-12
Relative molecular mass def
The weighted mean mass of a molecule of a compound, relative to one-twelfth of the mean mass of an atom of carbon-12
Ions to remember
NO3^- SO4^2- CO3^2- OH^- NH4^+
How many particles in one mole(Avogadro’s constant)
6.02x10^23 particles in one mole
Useful moles equations
-Moles=mass/Mr
-Moles=concentration x volume/1000
(Only when converting dm^3 to cm^3)
Moles = volume(dm^3)/24
Empirical formula def
The simplest whole number ration of atoms of each element present in a compound
Molecular formula def
The number and type of atoms of each element in a molecule
The true number of each atom on the molecule
What is an anhydrous substance?
Substance that contains NO water of crystallisation
What is a hydrated substance?
Substance that contains water of crystallisation
What is a standard solution?
A solution of known concentration
What is the limiting reactant in a reaction?
The reactant that is not in excess
Ideal gas equation
pV = nRT Where: p = pressure in Pa V = volume in m3 T = temperature in K n = moles, mol m = mass, in grams R = ideal gas constant - 8.31
-Only under standard conditions
-Temp: 298K/25C
Pressure: 100kPa/101kPA
What is the value for the ideal gas equation?
8.31