The hydrogen gas from the reaction of 1.0 g of iron with excess hydrochloric acid is collected in a 15.0 L flask at 25 degrees Celsius. What is the pressure of the hydrogen gas in this flask?

P = 0.03 atm

Explanation:

Given dа ta:

Mass of iron = 1.0 g

Volume of flask = 15.0 L

Temperature = 25 °C

Pressure of hydrogen gas = ?

Solution:

Chemical equation:

4HCl + 2Fe → 2FeCl₂ + 2H₂

Number of moles of iron:

Number of moles = mass / molar mass

Number of moles = 1.0 g / 55.85 g/mol

Number of moles = 0.02 mol

Now we will compare the moles of iron and hydrogen.

Fe : H₂

2 : 2

0.02 : 0.02

Pressure of hydrogen:

PV = nRT

P = nRT/V

P = 0.02 mol * 0.0821. atm. L/mol. K * 298 K / 15 L

P = 0.5 atm. L / 15 L

P = 0.03 atm