Question

How many grams of water are required to produce 5.50 L of hydrogen gas at 25.0°C and 755 mm Hg pressure according to the chemical equation shown below?

BaH₂(s) + 2 H₂O(l) → Ba(OH)₂(aq) + 2 H₂(g)
1) 2.01 g
2) 4.02 g
3) 4.07 g
4) 8.04 g

Answer 1

To find the grams of water needed to produce 5.50 L of hydrogen gas at specified conditions, use gas law calculations to determine the moles of hydrogen and stoichiometry to find the corresponding amount of water required, which is then converted to grams.

Step-by-step explanation:

To calculate how many grams of water are required to produce 5.50 L of hydrogen gas at 25.0°C and 755 mm Hg pressure, we need to use the ideal gas law and the stoichiometry of the reaction given by the chemical equation BaH₂(s) + 2 H₂O(l) → Ba(OH)₂(aq) + 2 H₂(g).

1. Convert the given pressure from mm Hg to atm by dividing by 760 mm Hg/atm.
2. Use the ideal gas law PV=nRT to calculate the moles of H₂ produced.
3. Utilize the stoichiometry of the chemical reaction to determine the moles of H₂O needed.
4. Finally, convert moles of H₂O to grams using the molar mass of water (18.02 g/mol).

The detailed calculations would result in the mass of water needed to produce the specified amount of hydrogen gas.