Moles a militros

N = the number of particles

NA = 6.02*10^23 particles/mol

n = moles

N = n * NA

mass / molar mass = mol

n = N /NA

percent composion of s = mass of s / mass of compund *100

Identifying limiting reactant :

1) masses to moles

2)use mole ration

3) limiting reactant is the one that is with the smallest num

Percent yield:

1)Divide given yeild by the limiting reactant

2) multiply by 100

Finding the Formula of a Hydrate:

 1. Find the # of g of MN and # of g of H 2 O.

 2. Convert g to mol.

3. Divide each “# of mol” by the smallest “# of mol.”

4. Use the ratio to find the hydrate’s formula.

Mass percent of water in Ba(OH)2 . XH2O

= (Total mass of sample) - (Mass of Ba(OH)2 in sample) / (Total mass of sample)  * 100

Ba(OH)2

molar mass molecular mass /molar mass empirical formula  then multiply by formula