# Question #dc69a

Apr 22, 2016

$9.45 g$

#### Explanation:

ok so first find the moles of iron in $19.69 g$
use the formula $m o l = \frac{m a s s}{a r}$ ar is the atomic relative mass.
$m o l = \frac{19.69}{56}$
$m o l = 0.3516 \approx 0.35$
now from the equation we know that 2 moles of aluminium make 2 moles of iron.now use the ratio method to get the moles of aluminium in $0.35 m o l s$.so it will be $0.35 m o l s$ as they both have the same ratio.
so now use these moles to find the mass of aluminium
$m o l = \frac{m a s s}{a r}$
$0.35 \cdot 27 = m a s s$
$9.45 g$