Super-Earths are the common exoplanets with a few earth radii. Their bulk composition remains a question, as their radius and mass can correspond to a relatively thick atmosphere on a silicate core or an H2O-rich mantle. Atmospheric characterization is expected to resolve this degeneracy. However, the specific criterion of either scenario is unclear. Previous work pointed out that, in the former case where the rocky part is in contact with the atmosphere, the rock can be molten (i.e., magma) depending on the temperature and the efficient chemical interaction between the atmosphere and the magma would produce atmospheric H2O (Kite et al., 2020). However, atmospheric H2O can naturally be present in the latter scenario, which results in a similar H2O-enriched atmosphere. Other radiatively active species, including C-bearing species, may provide additional clues. To spectrally resolve the degeneracy in the bulk composition, we study the atmospheric composition of super-Earths with exposed magma as a function of the magma redox state before the reaction, focusing on H, O, and C-bearing species. We find that the atmospheric C/H ratio can increase up to 100 times the initial values due to the substantially higher solubility of H2O into magma than C-bearing species. We show the specific trend between the abundance of H2O and the maximum C/H ratio as a function of the planetary mass, radius, and equilibrium temperature. Such a trend may be a useful probe of the presence of exposed magma when the chemical survey of a large population of super-Earths becomes available. We also quantitatively examine the effect of other mechanisms affecting the atmospheric C/H ratio, including atmospheric escape and mantle convection.