decresing pressure?

[donaldduck]

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how does decreasing the atmospheric pressure cause a substance to go to a solid to a gas. I thought that decreasing the pressure causes a substance to go into a it a state of less entropy? where am i wrong?

 

[Rabolisk]

Gas molecules are typically far apart, and have minimal interactions with each other. Low pressure would favor that. The phase diagram clearly shows that gas is favored at high temperature and low pressure.

 

[SoonerLuke]

how does decreasing the atmospheric pressure cause a substance to go to a solid to a gas. I thought that decreasing the pressure causes a substance to go into a it a state of less entropy? where am i wrong?

Decreasing the pressure favors a state of MORE entropy. Thus, decreasing the atmospheric pressure would tend to favor the gas because a gas has a higher "entropy value" than a solid. If you want a common sense/ stupid way to think about it, just think about "squeezing" the molecules of air really hard, i.e. increasing the pressure. You would compact them and make them more likely to form a solid haha