In a well-insulated container, 10.0 g solid octane at its freezing point (–56.9 °C) is added to 300. — Thermochemistry Chemistry Question

In a well-insulated container, 10.0 g solid octane at its freezing point (–56.9 °C) is added to 300.0 mL liquid octane at 0.0 °C (density = 0.71 g mL^-1). After equilibrium is achieved, the temperature is –6.3 °C. When the experiment is repeated under the same conditions except with 100.0 g solid octane, what is the final temperature?