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?

4.014 g of water

Explanation:

An internet search for your question tells me that the chemical equation is:

So first we use PV=nRT to calculate the moles of hydrogen gas produced:

0.993 atm * 5.50 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 298.16 K

Now we convert mol H₂ to mol H₂O and finally to grams of water:

0.223 mol H₂ * = 4.014 g H₂O

the correct answer to this question is 2