The interactions of Mo(a⁷S₃) and Mo(a⁵S₂) with methane, CH₄, and ethane, C₂H₆, were studied under single collision conditions using the crossed molecular beams technique. Ground state Mo(a⁷S₃) atoms were found to be unreactive at all collision energies studied up to <E_coll> = 35.4 kcal/mol. Non-reactive scattering of Mo(a⁷S₃) was studied with methane and ethane and compared to collisions with Ne and Ar. A forward peaking center-of-mass angular distribution, T(Q), was used to simulate the elastic collisions with inert gases as well as inelastic collisions with the alkanes. At a collision energy of 14.4 kcal/mol with CH₄ and 21.0 kcal/mol with C₂H₆, inelastic collisions were found to transfer ~10% and ~19% of the initial kinetic energy into alkane internal energy, respectively. For collisions of Mo(a⁵S₂) + CH₄, the dehydrogenation products, MoCH₂ + H₂, were observed at all collision energies studied down to 4.7 kcal/mol. The reaction Mo(a⁵S₂) + C₂H₆ ® MoC₂H₄ + H₂ was observed down to <E_coll> = 6.7 kcal/mol. For a given total energy (electronic + translational), it was found that electronic energy was highly effective in promoting chemical reaction whereas translational energy was ineffective.