Question

$4Co+3O_2\to 2C{o}_2{O}_3$
$66.8g$ of Cobalt reacted with oxygen and $70.50g$ of $C{o}_2{O}_3$ was collected after the reaction was completed. Calculate the percent yield. (At. mass of $Co=59g/mol$)

• A. $75$%
• B. $80$%
• C. $85$%
• D. $90$%

Answer 1

The correct option is A $75$%

$4Co+3O_2\to 2C{o}_2{O}_3$

$4moles$ of cobalt produce $2moles$ of $C{o}_2{O}_3$

$\Rightarrow 2mole$ $Co\to$ $1moleC{o}_2{O}_3$

$\Rightarrow 2\times 59\to (2\times 59+3\times 16)$

$\Rightarrow 118gCo\to 166gC{o}_2{O}_3$

$\Rightarrow 66.8g\to \left(x\right)$

$\Rightarrow x=\frac{166\times 66.8}{118}=93.97g$

$\%$ Yield $=\frac{70.50}{93.97}\times 100\approx 75\%$