Assume that helium is a perfect gas and that the volume of a cylinder containing helium is independent of temperature.A cylinder of helium at +85ºC has a pressure of 208 atm.The pressure of the helium when it is cooled to -55ºC is
A)-132 atm
B)127 atm
C)335 atm
D)132 atm
E)204 atm

Question

Quizplus · Accepted Answer

The pressure of a gas related to temperature can be described by the ideal gas law, $P_1/T_1 = P_2/T_2$, assuming the volume and the amount of gas remain constant. Convert temperatures to Kelvin: $T_1 = 85 + 273 = 358K$ and $T_2 = -55 + 273 = 218K$. Solve for $P_2$: $P_2 = P_1 \times (T_2/T_1) = 208 \times (218/358) \approx 127 atm$.

Assume That Helium Is a Perfect Gas and That the Volume