1.
a mole is a unit of measurement.
1 mole of anything = 6.022x10^23 units
this is called avagadros number
So 1 mole atoms = 6.022x10^23 atoms
1 mole molecules = 6.022x10^23 molecules
1 mole eggs = 6.022x10^23 eggs
To work out number of particles (weather atoms, or molecules or formula units) work out the number of moles, and then multiply by avagadros number.
2.
Yes, compounds are made up of atoms bonded together
sodium oxide is Na2O
1 molecule of Na2O contains
2 atoms of Na
And 1 atom of O
To add it to question 1
1 mole of Na2O has 6.022x10^23 molecules of Na2O
But each Na2O has 2 atoms of Na
So number of Na atoms in 1 mole Na2O = (2 x 6.022x10^23) Na atoms = 1.2044x10^24 Na atoms
Each Na2O has 1 atom of O
so 1 mole Na2O has 1 mole O atoms = 6.022x10^23 atoms of O
Each Na2O has 3 total atoms (2 O + 1 Na)
So total number of atoms in 1 mole Na2O = 3 moles
So number atoms = 3 x 6.022x10^23 atoms
= 1.8066x10^24 atoms in 1 mole Na2O
3.
molar mass of a compound = sum of atomic mass of every atom in the compound in grams
eg CH4 = 12.01 + (4 x 1.008) = 16.042 g/mol
4.
moles = mass / molar mass
the equation can be rearranged to solve for mass and molar mass
mass = moles x molar mass
molar mass = mass / moles
