Understanding Solubility
What is solubility?
Solubility is the amount of solute (generally a solid) that can dissolve in a solvent (generally a liquid). The solubility is the ability of the solute to dissolve in the solvent, this can be affected by the amount of the solute or solvent in the solution or the temperature applied to the solution. The solubility also varies depending on the substances themselves, for example, sugar is far more soluble in water than salt.
Go to this link to try out some solubility simulations
Source: breakingatom.com
The Science of Solubility
Solubility follows the rule of "like dissolves like", so polar solvents dissolve polar solutes. Furthermore, ionic substances dissolve in polar solvents because ionic substances are polar. Other than polarity, solubility is affected by temperature and sometimes pressure. When the temperature of a substance goes up the solubility rises proportionally. The opposite is also true with gasses; as temperature goes down, so does the solubility. Temperature affects solubility because the increase in kinetic energy from the increase of temperature makes it possible for the solvent molecules to more effectively and easily break apart the solute molecules and thus, bonding is easier. Pressure also affects solubility, but only of gasses, not of solids and liquids. As pressure increases, gas solubility increases proportionally, as is depicted in the photo below:
Source: unf.edu
How Does Solubility Relate to the Flint Situation?
Lead is normally insoluble in water. So how did it leech into Flint residents' water? The answer is corrosion, which occurs when a harsh substance is left in the water without a phosphate corrosion inhibitor to control it.
Look at the first photo on the left. As you can see, the water within the Detriot river had an added corrosion inhibitor, therefore less Cl- ions to corrode the lead pipes.
Now, look at the photo below that. The Flint river water lacked a corrosion inhibitor, and due also to increased Cl- and O2 from road salts seeping into the water, the water became highly corrosive.
Many of the pipes on Flint were made of lead. The lead within these pipes was corroded, and this process made the lead itself much more soluble within the water.
The final photo at the bottom shows how the metal (in the photo's case, iron, but in Flint, it was lead) becomes soluble in the water, causing it to turn a redd-ish/yellow color.
Created by Sophia Robinson, Matthew Kiernan, Ruby Keller
January 2021
works cited
“Rock Candy (Solubility Overview): Chemistry Simulations: CK-12.” CK, interactives.ck12.org/simulations/chemistry/solubility/app/index.html?screen=sandbox&lang=en&referrer=ck12Launcher&backUrl=https%3A%2F%2Finteractives.ck12.org%2Fsimulations%2Fchemistry.html
“Virtual Lab.” Temperature and the Solubility of Salts, chemcollective.org/vlab/87.
Brainard, Jean. “Solubility.” CK, CK-12 Foundation, 20 Nov. 2019, www.ck12.org/c/physical-science/solubility/lesson/Solubility-MS-PS/?referrer=featured_content.
Mott, Vallerie. “Introduction to Chemistry.” Lumen, courses.lumenlearning.com/introchem/chapter/solubility/#:~:text=Solubility%20is%20the%20relative%20ability,to%20dissolve%20into%20a%20solvent.
“Solubility of Elements and Compounds.” The Periodic Table of Elements, www.breakingatom.com/learn-the-periodic-table/solubility-of-elements-and-compounds.