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How to find the amount of moles of 10.0g of AL
(Grams of AL)(1mol/amu in grams) = Moles
10.0g)(1 mol/ 26.89g)= 0.37064

How to find amount of atoms in a specified amount 10.0g of AL
First convert 10.0g into mol = .37064 then find amount of atoms with avagadros number
(.37064mol AL)(6.022X10^{23}/1 mole AL)
Keep number in scientific notation

Steps to get from grams of a substance to number of atoms
 Grams to mole,
 Moles to atoms (avogardos number)

Equation for precent composition
Percentage = Part/whole X 100

How to find percent composition of carbon in C_{2}H_{5}OH
 Percent = Part/whole X 100
 First find the amu of the entire compd (46.068g/mol)
 Multiple C by number of

Empirical Formulas
The simplest whole number ratio of atoms in a molecule
H_{2}O_{2 > }HO

How to calculate empirical formulas from percent compositions?
Do this for all compositions, then divide all #s by the lowest amount of moles.
Multiply numbers by 2 or 3 to get whole numbers

Molecular formula
A multiple of the emp formula

How would you find the molecular formula of 252g of C_{5}H_{3} ?
 Find the mass of the 5C and 3H = 63.074 g/mol
 Then divide is with the mass you have.
then multiply emp1rical form by 4

How would you find molecular formula from percent compositions?
ex %49.47C, 5.191%H, 28.86%N, O, molec mass of 194g
 Make the %comp into grams.
 Divide that by elements amu
then you would divide that by the smallest amount of grams/mol

Determining amount of moles formed/ needed when reacting _{
}
 First you need to balance the equation.
 Then you use equivalence factors (4.30 moles of C_{3}H_{8} and O_{2 }= 4.30mol C_{3}H_{8 }= 5mol O_{2})
Then convert

