Question

Calculate the mass of hydrogen formed when 27g of aluminum reacts with excess hydrochloric acod according to the balance equetion belo. 2AL+ 6HCL- 2AlCl3+ 3H2

Answer 1

2Al + 6HCl → 2AlCl₃ + 3H₂

M(Al) = 27.0 g/mol

n(Al) $= \frac{27}{27} = 1 \;mol$

According to the reaction:

n(H₂) $= \frac{3}{2}n(Al) = \frac{3}{2} \times 1 = 1.5 \;mol$

M(H₂) = 2 g/mol

m(H₂) $= 1.5 \times 2 = 3 \;g$

Answer: 3 g