What mass of hydrogen gas is produced when 3.0 mol of iron react with excess hydrochloric acid according to the reaction below
2Fe + 6HCl --> 2FeCl3 + 3H2
To determine the mass of hydrogen gas produced, we need to use the balanced chemical equation and convert from moles to grams.
First, let's find the molar mass of hydrogen gas (H2). The atomic mass of hydrogen is approximately 1.01 g/mol. Since there are two hydrogen atoms in one molecule of hydrogen gas, the molar mass of H2 is 2.02 g/mol.
Next, we need to use the stoichiometry of the balanced chemical equation to determine the number of moles of hydrogen gas produced. The coefficient in front of H2 in the balanced equation is 3, indicating that 3 moles of hydrogen gas are produced for every 2 moles of iron (Fe).
Given that we have 3.0 moles of iron, we can set up a proportion to find the number of moles of hydrogen gas:
(3 moles H2 / 2 moles Fe) = (x moles H2 / 3.0 moles Fe)
Solving for x, the number of moles of hydrogen gas:
x = (3 moles H2 / 2 moles Fe) * 3.0 moles Fe
x = 4.5 moles H2
Finally, we can use the molar mass of hydrogen gas to convert moles to grams:
mass of H2 = 4.5 moles H2 * 2.02 g/mol
mass of H2 = 9.09 g
Therefore, when 3.0 moles of iron react with excess hydrochloric acid, the mass of hydrogen gas produced is 9.09 grams.