Question

This week, we learn about mixtures and solutions. How many times have you put (or seen someone else put) sugar into iced tea and seen the sugar sink to the bottom? Contrast this approach to making Sweet Tea – where tea is heated up, sugar is dissolved while hot, and then allowed to cool. In Sweet Tea, the sugar stays in solution instead of falling to the bottom. Using your understanding of temperature, mixtures, and solutions, describe why one method results in dissolved sugar while the other does not.

Answer 1

As the temperature of a solution is increased, the average kinetic energy of the molecules that make up the solution also increases. This increase in kinetic energy allows the solvent molecules to more effectively break apart the solute molecules that are held together by intermolecular attractions.

The average kinetic energy of the solute molecules also increases with temperature, and it destabilizes the solid state. The increased vibration (kinetic energy) of the solute molecules causes them to be less able to hold together, and thus they dissolve more readily.

So, in short we can say that for almost substance , solubility increases with increasing temperature.

That's why in cold tea we see sugar at bottom but in hot tea all the sugar get dissolved.