Question

Ozone reacts completely with NO, producing NO₂ and O₂. A 20.0 L vessel is filled with 1.00 mol of NO and 1.00 mol of O₃ at 397.0 K. Find the partial pressure of each product and the total pressure in the flask at the end of the reaction.

Part 1: P NO2= ____ atm

Part 2: P O2= ____ atm

Part 3: P total= ____ atm

Answer 1

The reaction is

NO + O₃ --> NO₂ + O₂

Given amount of NO = 1 mol

Given amount of O₂ = 1 mol

since we have the equal amounts of gases, their partial pressures are half of the total pressure.

The total pressure in flask at the end of the reaction can be calculated by using below formula,

PV = nRT

Where P = total pressure = ?

V = volume of the flask = 20 L

n = total amount of gases = 1 mol + 1 mol = 2 mol

R = gas constant = 0.0820 L atm / mol K

T = temperature in Kelvin = 397 K

From the formula,

P = nRT / V

P = ( 2 mol × 0.0820 L atm / mol K × 397 K ) / 20 L

P = ( 65.108 / 20 ) atm

P = 3.26 atm

Partial pressure of NO₂ = partial pressure of O₂ = total pressure / 2

P_NO2 = P_O2 = P_Total /2 = 3.26 / 2 = 1.63 atm

P_NO2 = 1.63 atm

P_O2 = 1.63 atm

P_Total = 3.26 atm