Question

______grams of 3-Hydroxy propanal (M.W = 74 g/mol) must be dehydrated to produce $7.8g$ of acrolein (M.W = 56 g/mol) $\left(C_3{H}_{4}O\right)$ if the percentage yield is 64. (Round off to the Nearest Integer).

[Given: Atomic masses: C : 12.0 u, H : 1.0 u, O : 16.0 u]

Answer 1

$\text{Moles of acrolein}=\frac{7.8}{56}=0.14\text{mol}$
$\text{\% yield}=\frac{\frac{7.8}{56}}{x}\times 100=64$
$x=\frac{7.8\times 100}{56\times 64}=\frac{780}{56\times 64}\text{mol}$

Mass of 3-Hydroxy propanal is,
$W_{\text{reactant}}=\frac{780}{56\times 64}\times 74=16.11g$
$W_{\text{reactant}}\approx 16g$