A mother finds her daughter's mug of hot cocoa on a table an hour after she had been drinking it. As the mother pours out the cocoa, she sees brown solids in the bottom of the mug. How can this be explained? (1 point)

Question

All dissolved substances will come out of solution over time. If the mother waits long enough, then all of the powder will appear at the bottom of the mug.
This would only happen if too much cocoa powder was added in the first place, because the solubility should not change.
The cocoa was mixed with hot water, but some cocoa settled as it cooled because the solubility went down.
The cocoa was mixed with hot water, but some cocoa settled as it cooled because the solubility went up.

Answer 1

The most appropriate explanation for the brown solids present in the bottom of the mug is:

The cocoa was mixed with hot water, but some cocoa settled as it cooled because the solubility went down.

As the hot cocoa cools, the solubility of cocoa powder decreases, causing some of the dissolved cocoa to precipitate out as solids. This is a common phenomenon in solutions where temperature decreases, resulting in the reduction of solubility for some substances.