Question

Calculate the mass of hydrogen formed when 27 g of aluminum reacts with excess hydrochloric acid according to the balanced equation: 2 Al + 6 HCl → 2 AlCl₃ + 3 H₂

Answer 1

6.069 grams is the  mass of hydrogen formed when 27 g of aluminum reacts with excess hydrochloric acid.

Explanation:

Balanced equation for the reaction:

2 Al + 6 HCl → 2 AlCl₃ + 3 H₂

data given:

mass of aluminum = 27 grams

atomic mass of one mole of aluminum = 26.89 grams/mole

formula to calculate number of moles:

number of moles = $\frac{mass}{atomic mass of one mole}$

number of moles = $\frac{27}{26.89}$

                              = 1.004 moles of aluminum will react

from the balanced equation:

2 moles of Al reacted to form 3 moles of H2

1.004 moles of Al will produce x moles of H2

$\frac{3}{2}$ = $\frac{x}{1.004}$

x = 3.012 moles of H2 will be formed.

mass will be calculated as number of moles multiplied by atomic weight

mass of 3.012 moles of hydrogen ?(atomic weight of one mole H2 = 2.015 grams)

= 3.012 x 2.015

= 6.069 grams of H2 will be formed.