Calculate the amount of heat required to completely sublime 50.0 g of solid dry ice (CO₂) at its sublimation temperature. The heat of sublimation for carbon dioxide is 32.3 kJ/mol.

Key Concepts

Sublimation

Sublimation is the phase transition in which a substance changes directly from a solid to a gas without passing through the liquid phase. In the case of dry ice (solid CO2), it sublimates at temperatures below -78.5°C. Understanding sublimation is crucial for calculating the heat required for this process, as it involves the energy needed to overcome intermolecular forces in the solid state.

Heat of Sublimation

The heat of sublimation is the amount of energy required to convert one mole of a solid directly into a gas at a constant temperature and pressure. For carbon dioxide, this value is 32.3 kJ/mol, indicating the energy needed to break the bonds holding the solid structure together. This concept is essential for calculating the total heat required for sublimation based on the mass of the substance.

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). For carbon dioxide (CO2), the molar mass is approximately 44.01 g/mol. Knowing the molar mass is vital for converting the mass of dry ice (50.0 g) into moles, which is necessary for applying the heat of sublimation in calculations.