Calculate the pressure of a helium sample at −207.3°C and 768 mL if it exerts a pressure of 175 kPa at 25.0°C and 925 mL.
A)32.1 kPa
B)46.6 kPa
C)657 kPa
D)953 kPa
E)Not possible, since the pressure would have to be negative

Question

Quizplus · Accepted Answer

We can use the combined gas law to solve for the unknown pressure:

P1V1/T1 = P2V2/T2

We need to make sure both temperatures are in Kelvin, so let's convert them:

25.0°C + 273.15 = 298.15 K
-207.3°C + 273.15 = 65.85 K

Now we can plug in the values we know and solve for the unknown pressure:

175 kPa x 925 mL / 298.15 K = P2 x 768 mL / 65.85 K

P2 = 175 kPa x 925 mL x 65.85 K / (768 mL x 298.15 K) = 46.6 kPa

Therefore, the pressure of the helium sample at −207.3°C and 768 mL is 46.6 kPa.

Calculate the Pressure of a Helium Sample at −207