Answer to Question #86021 in General Chemistry for Enci Peng

Question

What mass of Br2 is needed to react with 27 g of aluminum? Round to two decimal places.



2Al + 3Br2 → 2AlBr3

Answer 1

The balanced equation for reaction of aluminium with bromine can be written as follows

$2Al+3Br_{2} \rightarrow 2AlBr_{3}$

$\frac{m(Al)}{N(Al) \cdot M(Al)}=\frac{m(Br_{2})}{N(Br_{2}) \cdot M(Br_{2})}$

$m(Br_{2})=\frac{m(Al) \cdot N(Br_{2}) \cdot M(Br_{2})}{N(Al) \cdot M(Al)}$

$M(Al)=1 \cdot 26.98=26.98 \; amu$

$M(Br_{2})=2 \cdot 79.9=159.8 \; amu$

​$m(Br_{2})=\frac{27 \cdot 3 \cdot 159.8}{2 \cdot 26.98} \approx 239.88 \; g$

Answer:

239.88 g