Based on the information given, carbon dioxide undergoes a spontaneous phase change from solid to gas at 20°C and 1.0 atmosphere, as described by the equation: CO2 (s) + energy → CO2 (g). Which diagram accurately depicts the molecular arrangement of CO2 after the sublimation is complete? Key: Ο = CO2 molecule A) _____________________________________ | | | Ο Ο Ο Ο Ο Ο Ο Ο Ο Ο Ο Ο Ο Ο Ο Ο | | | |_____________________________________| B) _____________________________________ | | | Ο | | Ο Ο Ο | | Ο | | Ο Ο | | Ο | | Ο | |_____________________________________| C) _____________________________________ | | | ΟΟΟ | | | | Ο Ο | | Ο Ο | | Ο Ο | | | |_____________________________________| D) _____________________________________ | | | | | | | ΟΟΟ | | ΟΟΟ | | ΟΟΟ | | | |_____________________________________| (Apologies for the rudimentary visuals.)
Chemistry · Middle School · Thu Feb 04 2021
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The correct diagram to depict the molecular arrangement of CO2 after the sublimation is complete is diagram B. Sublimation is the phase transition from a solid directly to a gas, bypassing the liquid state. When CO2 sublimates it changes from solid dry ice into CO2 gas. In the gas phase, the molecules of CO2 are much farther apart than in the solid phase and move freely, filling the container they are in. Hence, the arrangement of molecules is random and dispersed as shown in diagram B.
Diagram A represents a solid or a very tightly packed arrangement Diagram C suggests some form of structure that is not characteristic of gases and Diagram D is more representative of a liquid, where molecules are close but not as structured as in a solid. Therefore B is the best representation of gaseous CO2 after sublimation.