FREEZING AND MELTING GO ON AT THE SAME TIME

Ss Section 1.7 discussed, jTie/titigoccurs when a substance changes from solid to liquid and freezing occurs when a sulxstance changes from liquid to solid. 

The temperature 0 C is both the melting and the freezing temperature of water. At this temperature, water molecules in the liquid phase arc moving. slowly enough that they rend to clump together to form ice crystal —they freeze. At this same temperature, however, water molecules in ice are vibrating with sufficient commotion to break loose from the crystalline structure to form liquid water. 

For water, () C is the special temperdture at which the rate of ice formation equals the rate ofliquid water formation. In other words, it is the temperature at which 

Slowly moving H O molecules near freezing temperature 

At 0 C, ice crystals gain and lase water molecules simultaneously. 

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