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Chapter 5: Q 5.69 (page 199)

What happens when you spread salt crystals over an icy sidewalk? Why is this procedure rarely used in very cold climates?

Short Answer

Expert verified

The transition temperature between the phases will be lower than, implying that the ice on the street will not freeze until the temperature drops to the new phase temperature.

Step by step solution

01

Given information

Salt crystals are spread over an icy sidewalk.

02

Explanation

We know that water freezes at 0掳C, thus sprinkling salt on the icy sidewalk will lower the phase temperature. As a result, the transition temperature between the phases will be lower than 0掳C, implying that the ice on the street will not freeze until the temperature drops to the new phase temperature.

This approach will not work in very cold nations since the temperature is below the phase temperature of the water and salt mixture, and the mixture also causes concrete damage, so it is only used in very cold countries on rare occasions.

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Most popular questions from this chapter

The compression factor of a fluid is defined as the ratio PV/NkT; the deviation of this quantity from 1 is a measure of how much the fluid differs from an ideal gas. Calculate the compression factor of a Van der Waals fluid at the critical point, and note that the value is independent of a and b. (Experimental values of compression factors at the critical point are generally lower than the Van der Waals prediction, for instance, 0.227 for H22O, 0.274 for CO22, and 0.305 for He.)

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