# Problem: The solubility of Cr(NO3)3 •9 H2O in water is 208 g per 100 g of water at 15 oC. A solution of Cr(NO3)3 •9 H2O in water at 35 oC is formed by dissolving 313 g in 100 g water. When this solution is slowly cooled to 15 oC, no precipitate forms.You take a metal spatula and scratch the side of the glass vessel that contains this cooled solution, and crystals start to appear. What has just happened?

###### FREE Expert Solution

We are asked what happened when you take a metal spatula and scratch the side of the glass vessel that contains a cooled solution of Cr(NO3)3•9 H2O and crystals start to appear.

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###### Problem Details

The solubility of Cr(NO3)3 •9 H2O in water is 208 g per 100 g of water at 15 oC. A solution of Cr(NO3)3 •9 H2O in water at 35 oC is formed by dissolving 313 g in 100 g water. When this solution is slowly cooled to 15 oC, no precipitate forms.

You take a metal spatula and scratch the side of the glass vessel that contains this cooled solution, and crystals start to appear. What has just happened?