A student determines the empirical formula of an unknown metal oxide, \(\text{M}_x\text{O}_y\), by heating a weighed sample of pure metal \(\text{M(s)}\) in an open porcelain crucible to completely convert it to the solid oxide. Before the initial weighing of the empty crucible, an improperly adjusted, yellow burner flame deposited a thin layer of carbon soot, \(\text{C(s)}\), onto the exterior of the crucible. The student recorded the mass of the sooty crucible, added the metal, recorded the combined mass, and then heated the crucible strongly with a clean, hot blue flame until the metal was fully oxidized and all the exterior soot had combusted to \(\text{CO}_2\text{(g)}\). Based on this experimental error, which of the following predicts the effect on the calculated \(\text{O}:\text{M}\) mole ratio in the metal oxide product, and provides the correct justification?