  The generalized Chaplygin gas model (GCGM) contains 5 free parameters, here,
they are constrained through the type Ia supernovae data, i.e., the ``gold
sample'' of 157 supernovae data. Negative and large positive values for
$\alpha$ are taken into account. The analysis is made by employing the Bayesian
statistics and the prediction for each parameter is obtained by marginalizing
on the remained ones. This procedure leads to the following predictions:
$\alpha = - 0.75^{+4.04}_{-0.24}$, $H_0=65.00^{+1.77}_{-1.75}$, $\Omega_{k0} =
- 0.77^{+1.14}_{-5.94}$, $\Omega_{m0} = 0.00^{+1.95}_{-0.00}$, $\Omega_{c0} =
1.36^{+5.36}_{-0.85}$, $\bar A = 1.000^{+0.000}_{-0.534}$. Through the same
analysis the specific case of the ordinary Chaplygin gas model (CGM), for which
$\alpha = 1$, is studied. In this case, there are now four free parameters and
the predictions for them are: $H_0 = 65.01^{+1.81}_{-1.71}$, $\Omega_{k0} = -
2.73^{+1.53}_{-0.97}$, $\Omega_{m0} = 0.00^{+1.22}_{-0.00}$, $\Omega_{c0} =
1.34^{+0.94}_{-0.70}$, $\bar A = 1.000^{+0.000}_{-0.270}$. To complete the
analysis the $\Lambda$CDM, with its three free parameters, is considered. For
all these models, particular cases are considered where one or two parameters
are fixed. The age of the Universe, the deceleration parameter and the moment
the Universe begins to accelerate are also evaluated. The quartessence
scenario, is favoured. A closed (and in some cases a flat) and accelerating
Universe is also preferred. The CGM case $\alpha = 1$ is far from been ruled
out, and it is even preferred in some particular cases. In most of the cases
the $\Lambda$CDM is disfavoured with respect to GCGM and CGM.
