If the specific heat of a marshmallow is 2 J/g, how much heat is given off when it cools from room temp (25C) to its liquid nitrogen bath. Weight of the marshmallow 7.4g

Answer 1

q = mass marshmallow x specific heat x (Tfinal-Tinitial).
You have the mass and specific heat and Ti. You will need to supply Tf; I wonder why you have it in an liquid N2 bath to begin with.