Chapter 5: Lesson 1

Chapter 5: Lesson 1

Understanding Solutions​

Solutions

• A solution is a mixture containing a solvent and at least one solute; it has the same properties throughout

  • Solvent: the part of the solution present in the largest amount; it dissolves the other substances​

  • Solute: ​the substance that is dissolved by the solvent

• Example: salt water- water is the solvent and salt is the solute

• "universal solvent" = water ​

Other solvents

• A solution can be a combination of gases, liquids, or solids

• Air is an example of a solution made of nitrogen, oxygen, and other gases

• Metal allows like bronze, brass, and steel are solutions of different solid elements ​

​Colloid

• A colloid is a mixture containing small, undissolved particles that do not settle out

• The particles are too small to be seen without a microscope, but large enough to scatter beam of light

• Examples: Milk, shaving cream, ​smoke

Suspensions

• A suspension is a mixture in which particles can be seen and easily separated by settling or filtration

• Contains visible particles that are larger than the particles in solutions or colloids ​

​ Solution Colloid Suspension

Ionic and molecular solutes

• A solution forms when particles of the solute separate from each other and ​become surrounded by the particles of a solvent

• The positive and negative ions of the solute are attracted to the partially charged ​polar water molecules

• Water molecules will surround all of the ions, and the solid crystal will be completely dissolved​

Solutes and conductivity

• Ionic compounds in water conduct electric current, but a solution of molecular compounds may not.

  • If ions are present, electric current will flow- the solute must be salt​

effects of solutes

• Solutes raise the ​boiling point of a solution above that of the solvent

• Solutes lower the freezing point of a solution below that of the solvent alone

  • Example: salt on icy roads​

• The temperature must drop below 0 degrees Celsius in order for the solution to freeze ​