Question

Bacteria and viruses are inactivated by temperatures above 139 ∘C in an autoclave. An autoclave contains steam at 1.00 atm and 100 ∘C. At what pressure, in atmospheres, will the temperature of the steam in the autoclave reach 139 ∘C, if n and V do not change?

Answer 1

To answer this question, we will use pressure law which states that:
"At constant volume of a fixed mass of gas, the pressure of the gas is directly proportional to the temperature"

This means that:
Pi / Ti = Pf / Tf where:
Pi is the initial pressure = 1 atm
Ti is the initial temperature = 100 + 273 = 373 degree kelvin
Pf is the final pressure that we want to calculate
Tf is the final temperature = 139 + 273 = 412 degree kelvin

Substitute in the equation with the givens to calculate the pressure as follows:
1 / 373 = Pf / 412
Pf = (1/373) * 412 = 1.104557641 atm