Watch the "2017 Demolition Derby" video from 6:34 to 6:50.

https://www.youtube.com/watch?v=Ds1NalU84P4

In the video above, you saw part of a demolition derby. The demolition derby is a large scale of what occurs when the dissolving process takes place.What happens during the process of dissolving? All molecules are in constant motion, so they run into each other. Molecules of the solvent bombard molecules of solute.

• Collision of molecules is what makes substances dissolve (see image 1).
• This breaking up process is called dissolving.

Check out the following video to learn more about dissolving:

https://youtu.be/0cPFx0wFuVs

Image 1: Andy Schmitz, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>,
​via Wikimedia Commons

When discussing the dissolving process, there are different factors that will affect this process. Stirring, temperature and surface area affect the rate at which a substance dissolves because they affect the rate of collisions between solute and solvent molecules.

• Stirring: Affects the rate at which a solid solute dissolves. It does not influence the amount of solute that will dissolve.
• Increase in Temperature: Particles move more quickly, so particles collide more often between the solvent and solute particles which increases the rate of dissolution (dissolving).
• Increase in Surface Area: Increasing the surface area of solute means the solid is broken down into smaller pieces or ground into a powder, so a larger area where the solvent and solute particles can interact will increase the rate of dissolution. This occurs because there is a greater chance of the particles colliding.

To learn more about these three factors watch the following video from 1:31 to 2:56:

https://youtu.be/WHW2Ek1KDuY

The Solubility Curve

The amount of solute a certain amount of solvent can dissolve is different for every solute. For example, at 90 degrees C, 100 g of water can dissolve 40 grams of NaCl; however, 100 g of water could dissolve 55 g of KCl. The same amount of water at the same temperature can dissolve different amounts based on what the solute is. A solubility curve is a graph showing the solubility of a substance at different temperatures (see image 2). Also, the solubility curve can be used to identify unknown solutions. Check out the following video to learn more about the solubility curve.

https://youtu.be/7AZ2Z6_CQmA

Image 2: Brightyellowjeans, CC BY-SA 4.0 <https://creativecommons. org/licenses/by-sa/4.0>, via Wikimedia Commons