I have the $\Delta T$, I have the specific heat of the calorimeter, I have known weights/mass. I know the salt is lithium-based. What steps do I take to calculate the enthalpy of the solution so I can compare my answer to the specific molar enthalpies of possible lithium salts?

If the equation I use is $Q = m \times c \times \Delta T$, what mass do I use and do I use the specific heat of the calorimeter?

I just don't understand this. I've been hitting my head off the problem with research and trying to attack it from different directions and I'm just stuck.