A 10.150g sample of a compound known to contain phosphorus and oxygen yields 5.717 g of oxygen. Find the empirical formula of the compound

The empirical formula is

Explanation:

Mass of O = 5.717 g

Mass of P= (10.150-5.717) g = 4.433 g  

Step 1 : convert given masses into moles.

Moles of O =

Moles of P=  

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For O =  

For P =

The ratio is to be converted to whole number

Thus whole number ratio of O : P =

Hence the empirical formula is

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"