contestada

Consider the reaction CaCN2 + 3 H2O → CaCO3 + 2 NH3 . This reaction has a 75.6% yield. How many moles of CaCN2 are needed to obtain 18.6 g of NH3?
a. 0.547 mol
b. 209 mol
c. 0.414 mol
d. 1.65 mol
e. 478 mol
f. 0.724 mol

Respuesta :

Answer: Thus 0.724 mol of [tex]CaCN_2[/tex] are needed to obtain 18.6 g of [tex]NH_3[/tex]

Explanation:

To calculate the moles :

[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]    

[tex]\text{Moles of} NH_3=\frac{18.6g}{17g/mol}=1.09moles[/tex]

[tex]CaCN_2+3H_2O\rightarrow CaCO_3+2NH_3[/tex]

According to stoichiometry :

2 moles of [tex]NH_3[/tex] are produced by = 1 mole of [tex]CaCN_2[/tex]

Thus 1.09 moles of [tex]NH_3[/tex] will be produced by =[tex]\frac{1}{2}\times 1.09=0.545moles[/tex]  of [tex]CaCN_2[/tex]

But as yield of reaction is 75.6 %, the amount of [tex]CaCN_2[/tex] needed is =[tex]\frac{0.545}{75.6}\times 100=0.724[/tex]

Thus 0.724 mol of [tex]CaCN_2[/tex] are needed to obtain 18.6 g of [tex]NH_3[/tex]