# -----------------------------------------------------------------------------
import scipy.optimize
# -----------------------------------------------------------------------------


def model(x_list):
    ksi2 = x_list[0]    # First unknown variable x

    K = 0.016
    ksi1 = 490
    n_CO = 0.08*7000 - ksi1 + ksi2
    n_H2O = ksi2
    n_CO2 = 0.02*7000 - ksi2
    n_H2 = 0.75*7000 - 2*ksi1 - ksi2


    eq1 = (n_CO*n_H2O)/(n_CO2*n_H2) - K


    balance = [eq1]    # Packing into list for output

    return balance


guess_ksi2 = 60    # Initial guess for y
guess = [guess_ksi2]
ans = scipy.optimize.root(model, guess)
solution = ans['x']
x = solution[0]
print(f"ksi2 = {x}")