Final answer:
The correct equation for calculating the heat of reaction using calorimetry is q_reaction = -C_cal x Δt, signifying the relationship between the calorimeter constant, the temperature change, and the heat of the reaction.
Step-by-step explanation:
The question relates to the calculation of heat transfer during a chemical reaction in a calorimetry setup. The correct formula to calculate the heat of the reaction (qreaction) based on the calorimeter constant (Ccal) and the change in temperature (Δt) is qreaction = -Ccal × Δt. This formula indicates that the heat gained or lost by the reaction is equal to the product of the calorimeter constant and the temperature change, with a negative sign implying that the heat lost by the reaction is gained by the calorimeter (or vice versa).