If 4.000 grams of hydrogen peroxide is placed within a sealed 250.0 mL container at 500.0 K. What is the pressure of the oxygen gas produced in atmosphere?

Question

If 4.000 grams of hydrogen peroxide is placed within a sealed 250.0 mL container at 500.0 K. What is the pressure of the oxygen gas produced in atmosphere?

Answer 1

The reaction taking place is the decomposition of hydrogen peroxide to form water and oxygen gas.

2H₂O₂(l) ==> 2H₂O(l) + O₂(g) .. balanced equation

moles H2O2 present = 4.000 g H2O2 x 1 mol / 34.00 g = 0.1176 mols

moles O2 produced = 0.1176 mols H2O2 x 1 mol O2 / 2 mols H2O2 = 0.05882 mols O2

Use the Ideal gas law to find the pressure exerted by the O2 gas:

PV = nRT

P = pressure in atm = ?

V = volume in L = 250.0 ml x 1 L / 1000 ml = 0.250 L

n = moles = 0.05882 moles

R = gas constant = 0.0821 Latm/Kmol

T = temperature in Kelvin = 500.0K

Solve for P:

P = nRT / V

P = (0.05882)(0,0821)(500) / 0.250

P = 9.659 atm