Question

For the following reaction, 6.12 grams of phosphorus (P4) are mixed with excess chlorine gas . The reaction yields 21.5 grams of phosphorus trichloride . phosphorus (P4) ( s ) chlorine ( g ) phosphorus trichloride ( l ) What is the theoretical yield of phosphorus trichloride

Answer 1

Answer: 27.1 gram

Explanation:

To calculate the moles :

$\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}$    

$\text{Moles of} P_4=\frac{6.12g}{124g/mol}=0.0494moles$

The balanced chemical reaction is:

$P_4(s)+6Cl_2(g)\rightarrow 4PCl_3(l)$

As $Cl_2$ is the excess reagent, $P_4$ is the limiting reagent as it limits the formation of product.

According to stoichiometry :

1 mole of $P_4$  give = 4 moles of $PCL_3$

Thus 0.0494 moles of $O_2$ give =$\frac{4}{1}\times 0.0494=0.198moles$  of $PCl_3$

Mass of $PCl_3=moles\times {\text {Molar mass}}=0.198moles\times 137g/mol=27.1g$

Thus 27.1 g  is the theoretical yield of phosphorus trichloride