English: The reduced inversion temperature of a Dieterici gas, as a function of its reduced pressure. Reproduced from Figure 17 of Pippard "Elements of Classical Thermodynamics" page 75.

```python import numpy as np import matplotlib.pyplot as plt

1. Define the range of y

y = np.linspace(0.1, 7.99, 400)

1. Define z based on y

z = 4 / (8 - y)

1. Calculate x based on y and z

x = np.exp(2 - 2/(y*z)) * y / (2*z - 1)

1. Create the plot

plt.figure(figsize=(6, 6)) # Set figsize to (6, 6) plt.plot(x, y) plt.scatter(1, 1, color='red', label="critical point") # Add a red spot at (1, 1) plt.xlabel('Reduced Pressure') plt.ylabel('Reduced Temperature') plt.legend() plt.grid(True) plt.show()

```