- the atomic mass is the mass of 1 mole of atoms of an element
Ex. the mass of 1 mole of 'C' atoms is 12.0 g - You can find the atomic mass of an element by simply looking for the element on a periodic table. The atomic mass is usually located at the bottom right of the element
- Diatomic consist of patterns such as: H^2, O^2, N^2, Cl^2, Br^2, I^2, F^2
- Polyatomic: P^4, S^8
- Since H^2 has 2 hydrogen atoms, all you have to do to find the molar mass is to get the atomic mass of the element and multiply it by 2.
Another example is O^2
0^2: O(2) 16.0g = 32.0g - FOR COMPOUNDS: you have to add the molar masses of all atoms involved
ex. H2O-> 2H= 2(1.0)
1O= 1(16.0)
18.0g/mol---> 1 mol=6.02x10^23 H2O molecules
Grams<------> Moles
- When converting, sometimes you have decipher between g/mol or mol/g
- Ex. Find the mass of 2.5 moles of water
2.5 mol H2Ox18.0g/1mol= 45 g
In the problem above ^ you first have to find the molar mass of H20, which equals 18.0g/mol. Looking back on the equation, you have to find the mass of 2.5 moles of water. So to find the mass you have to multiply 2.5 moles of water by the molar mass of H2O divided by 1 mol, since you're trying to get rid of moles. - Another example is: find the number of moles in a 391 g sample of Nitrogen Oxide
In this situation, you have to obviously find the molar mass. But this time, instead of multiplying 391g of Nitrogen Oxide with g/mol, you would have to switch it to mol/g. :
391g NO3x1mol/46g=8.5mol
You see above^ you have to get rid of grams, so you divide the equation by the molar mass( which is in grams )
The following is just another gag video about Avogadro's #
Video converting moles into grams
Video showing an example of the conversion of grams to moles