Adding heat energy to water increases the motion of the water molecules and the molecules of food coloring. The faster moving molecules cause the food coloring to mix into the water faster. The water molecules and food coloring molecules in cold water don't move as quickly as in hot water.

The net flow of solute is from its higher concentration to lower concentration.

This process is called nuclear fusion. It is found in the sun. Nuclear fission is a reaction in which two small nuclei combine together to form a big nuclei and release energy. This type of reaction takes place in sun and is the reason behind the massive amount of energy it sun provides.

The temperature and pressure at which all three phases of a substances coexist is called triple point​. By the definition.

Increasing the temperature of liquid, increases the average K.E. of the molecules. The molecules start moving vigorously in all the directions, thereby increasing and the inter-molecular space between them. Thus, the liquid changes into gas.

In general, the liquids tend to expand when their temperature increases. For example, the same mass of boiling water occupies more volume at 100 degrees Celsius than at 20 degrees Celsius. Therefore, increasing temperature decreases density.

As the pressure increases between the skates and ice, the ice starts melting below 0^o C.

Latent heat is a measure of the heat energy (Q) per mass (m) released or absorbed during a phase change. The SI units are joule per kilogram [J/kg]

When ice melts the volume decreases and an increase in pressure will support this phenomena according to Le Chatalier’s rule.

When a body changes its state or phrase it requires latent heat, rather than the specific heat.