Question

three samples of three different gases are listed in the table below. all the samples contain exactly 1 mole of gas and are at a temperature of - 15.0°c.
for each sample, decide whether the gas can be reasonably described as an ideal gas. if the gas isnt ideal, decide the most important reason why it isnt.

Explanation:

Step1: Calculate the ideal gas volume

The ideal gas law is \(PV = nRT\). Given \(n = 1\space mol\), \(T=- 15.0^{\circ}C=(273 - 15)K = 258K\), \(R = 0.0821\space L\cdot atm/(mol\cdot K)\).
So, \(V=\frac{nRT}{P}=\frac{1\times0.0821\times258}{P}\)

Step2: Analyze sample A

For sample A, \(P = 1.4\space atm\)
\(V_{ideal}=\frac{1\times0.0821\times258}{1.4}\approx15.1\space L\)
Since \(V_{actual}=20.0\space L
eq V_{ideal}\), and at relatively low pressure (\(P = 1.4\space atm\)), the main deviation is due to particle - particle attractions.

Step3: Analyze sample B

For sample B, \(P = 0.71\space atm\)
\(V_{ideal}=\frac{1\times0.0821\times258}{0.71}\approx30.0\space L\)
Since \(V_{actual} = V_{ideal}\), the gas can be described as an ideal gas.

Step4: Analyze sample C

For sample C, \(P = 0.48\space atm\)
\(V_{ideal}=\frac{1\times0.0821\times258}{0.48}\approx44.1\space L\)
Since \(V_{actual}=40.0\space L
eq V_{ideal}\), and at very low pressure (\(P = 0.48\space atm\)), the main deviation is due to particle - particle attractions.

Answer:

sample	pressure (atm)	volume (L)	ideal?	If not ideal, the most important reason why not:
B	0.71	30.0	yes	-
C	0.48	40.0	no	There are attractions between the particles.