Oxidation number is charge of element in compound. Can be neutral, positive or negative.
Oxygen in dichromate has oxidation number -2, becauce there are seven oxygens, net oxidation number of oxygen is -14.
2·x(oxidation number of Cr) + 7· (-2) = -2 2x= +12
x= +6, oxidation number of one chromium is +6.
Delta enthalpy = 2x386-3x1x432-3x942=-3350kJ/mol
It's because of Avagadro's number.
- It is known as Avagadro's constant too.
- It states that at constant temperature one mole of any substance contain same number of atoms i.e n no of atoms
where
P S
4 10
you just use the roots given in the molecular formula
