Ancient air is trapped in bubbles deep within polar ice. The bubbles get fewer and smaller...

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Ancient air is trapped in bubbles deep within polar ice. The bubbles get fewer and smaller as the depth of ice gets deeper. These decreases are the result of the formation of an air hydrate phase. However, both bubbles and air hydrate coexist, even when only the hydrate phase is expected to form. P. B. Price [Science, 267, 1802 (1995)] explains this by postulating a layer of air hydrate around each bubble. To form more hydrate, water must diffuse through the hydrate to the inner surface of the bubble; the diffusion coefficient for this process is cm D = 2100- -exp sec -1.5. 10-¹9 J/kBT As the water reaches the inner surface of the hydrate, it reacts to form more hydrate, so the resistance to water diffusion increases with time. Estimate the time to react all the air at -46 °C (the temperature of South Pole ice) in a 0.01-cm bubble of air at 1 atm. Hint: You can assume pseudo-steady state and that the water and hydrate densities are the same. Ancient air is trapped in bubbles deep within polar ice. The bubbles get fewer and smaller as the depth of ice gets deeper. These decreases are the result of the formation of an air hydrate phase. However, both bubbles and air hydrate coexist, even when only the hydrate phase is expected to form. P. B. Price [Science, 267, 1802 (1995)] explains this by postulating a layer of air hydrate around each bubble. To form more hydrate, water must diffuse through the hydrate to the inner surface of the bubble; the diffusion coefficient for this process is cm D = 2100- -exp sec -1.5. 10-¹9 J/kBT As the water reaches the inner surface of the hydrate, it reacts to form more hydrate, so the resistance to water diffusion increases with time. Estimate the time to react all the air at -46 °C (the temperature of South Pole ice) in a 0.01-cm bubble of air at 1 atm. Hint: You can assume pseudo-steady state and that the water and hydrate densities are the same.

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Estimating Time for Air Consumption in Polar Ice Bubble Given Diffusion coefficient D 2100 cms exp15 ... View the full answer