Nitrate salts (NO3-), when heated, can produce nitrites (NO2-) plus oxygen (O2). A sample of potassium nitrate is heated, and the O2 gas produced is collected in a 720 mL flask. The pressure of the gas in the flask is 2.9 atm, and the temperature is recorded to be 319 K. The value of R = 0.0821 atm L / (mol K)

How many moles of O2 gas were produced?

After a few hours, the 720 mL flask cools to a temperature of 293K.

Pnew = atm

What is the new pressure due to the O2 gas?

Question

Engineering

Valery Noble

31 July, 17:33

Nitrate salts (NO3-), when heated, can produce nitrites (NO2-) plus oxygen (O2). A sample of potassium nitrate is heated, and the O2 gas produced is collected in a 720 mL flask. The pressure of the gas in the flask is 2.9 atm, and the temperature is recorded to be 319 K. The value of R = 0.0821 atm L / (mol K)

How many moles of O2 gas were produced?

After a few hours, the 720 mL flask cools to a temperature of 293K.

Pnew = atm

What is the new pressure due to the O2 gas?

+2

Answers (1)

Know the Answer?

Rex Butler · Answer 1

0.07973 moles of O2 gas were produced

2.66 atm

Explanation:

Using the ideal gas equation

PV = nRT

P = pressure = 2.9 atm

V = volume = 720 mL = 720mL/1000 = 0.72 L

n = number of moles = ?

R = the gas constant = 0.0821 atm L / (mol K)

T = temperature in Kelvin = 319 K

make n subject of the formula

n = PV/RT

n = 2.9 atm x 0.72 L / 0.0821 atm L / (mol K) x 319K = 0.07973 moles of O2 gas were produced

Pnew = atm?

P = nRT/V

= 0.07973 x 0.0821 atm L / (mol K) x 293K/0.72 L = 2.66 atm