Question

calculate the mass hydrgen formed when 25 grams of aluminum reacts with excess hydrochloric acid

Answer 1

$2Al + 6HCl → Al_2Cl_6 + 3H_2$

$Mole [Al]=\frac{ 25(g) }{ 26.98 (g/mol) }= 0.93 moles$

$Moles (Hydrogen) = \frac{3×0.93}{2 }= 1.40 moles$

$Mass(H_2) = 1.40 × 2.00 = 2.80 g$