When you add cold milk and hot chocolate, they will slowly blend as the cooler liquid mixes with the warmer liquid. Eventually, the heat will be spread out evenly through the entire liquid. Which statement best explains why this happens?

Question

A. The molecules of the two liquids form chemical bonds to spread energy.
B. Heat always moves from areas of higher temperature to areas of lower temperature.
C. Cold liquids rise and hot liquids sink making the liquids mix.
D. The liquids attract each other because the densities of the liquids are the same.

Answer 1

B. Heat always moves from areas of higher temperature to areas of lower temperature.

This statement best explains the process described. The heat from the hot chocolate will transfer to the cold milk until thermal equilibrium is reached, causing the temperature to equalize throughout the mixture.