A metal reacts with acid to form hydrogen gas as shown by the following equation.

M(s) + 2 H⁺(aq) $\rightarrow$ M²⁺(aq) + H₂(g)
What is the atomic weight of this metal if 3.49 grams of the metal generates enough hydrogen collected over water to fill a bottle with a volume of 2.20 L at 25.0°C and 1.00 atmosphere pressure under conditions where the vapor pressure of the solution is 23.8 torr?

Question

A metal reacts with acid to form hydrogen gas as shown by the following equation.

M(s) + 2 H⁺(aq)

\rightarrow

M²⁺(aq) + H₂(g)
What is the atomic weight of this metal if 3.49 grams of the metal generates enough hydrogen collected over water to fill a bottle with a volume of 2.20 L at 25.0°C and 1.00 atmosphere pressure under conditions where the vapor pressure of the solution is 23.8 torr?

Quizplus · Accepted Answer

Using the ideal gas law and correcting for vapor pressure, the moles of hydrogen gas can be calculated. Then, using stoichiometry, the moles of metal can be determined. Dividing the mass of the metal by the moles gives the atomic weight, which is approximately 40.0 g/mol.

A Metal Reacts with Acid to Form Hydrogen Gas as Shown