Question

A sample of hydrogen (H2) gas at 123 ∘C and has a pressure of 2.90 atm .At what final temperature, in degrees Celsius, will the pressure of the H2 decrease to 0.18 atm , if volume and amount of gas do not change?Express your answer using three significant figures.

Answer 1

In this question, we have a situation where a change in temperature and pressure occurs while the volume is kept constant, and in this situation, we have to use the Gay-Lussac's gas law formula to solve it, the formula is:

P1/T1 = P2/T2

Where:

P1 = initial pressure, 2.90 atm

T1 = initial Temperature in Kelvin, 123°C or 396 Kelvin

P2 = Final pressure, 0.18 atm

T2 = Final Temperature in Kelvin, ?

Now we add these values into the formula:

2.90/396 = 0.18/T2

0.0073 = 0.18/T2

T2 = 0.18/0.0073

T2 = 24.6 Kelvin of temperature, or -248 Celsius