contestada

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

Respuesta :

Answer: The empirical formula is [tex]P_2O_5[/tex]

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 =[tex]\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{5.717g}{16g/mole}=0.357moles[/tex]

Moles of P=[tex]\frac{\text{ given mass of P}}{\text{ molar mass of P}}= \frac{4.433g}{31g/mole}=0.143moles[/tex]  

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

For O = [tex]\frac{0.357}{0.143}=2.5[/tex]  

For P =[tex]\frac{0.143}{0.143}=1[/tex]

The ratio is to be converted to whole number

Thus whole number ratio of O : P = [tex]2.5\times 2:1\times 2=5: 2[/tex]

Hence the empirical formula is [tex]P_2O_5[/tex]