1. Mixtures & Solutions Notes

4. Vocabulary Definitions!
Mixture: a material system made up of two or more pure substances which can be separated physically.
Ex: soil
Homogeneous mixture: mixture with uniform composition and properties throughout (also called a solution).
Ex: milk
Heterogeneous mixture: mixture that is not uniform in its composition
Ex: salad dressing

6. What is a solvent? What is a solute?

7. How can you keep track of compounds when in solution?
Concentration: a measure of the amount of solute dissolved in a specified volume of solution
Molarity (M): the concentration of a solution expressed in moles of solute per liter of solution.
Molality: the concentration of a solution expressed in moles per kilogram of solution.

8. Observe the Gummy Bears & Answer the following questions
Observe the Gummy Bears & Answer the following questions. Turn your answers in with your lab.
In general, why do you think the gummy bears changed size?
The gummy bears changed size because the concentration of the gummy bears were different than the concentration of the solutions they were submerged in.

9. Rule of Concentration Gradients
Concentration gradient: the process of particles (solutes) moving through a solution or gas from an area of higher number of particles to an area of lower number of particles. The areas are typically separated by a barrier or membrane.
All substances will move from areas of higher concentration to lower concentration (Ex. Heat, solutes, solvents)

10. Gummy Bear Inflation Through Osmosis

11. What are other ways of communicating the concentration of solutions?
Parts per million (ppm) – used for solutions with very small quantities of solute
Parts per billion (ppb) – used for solutions with VERY VERY small quantities of solute
Percent concentration by mass (%) - part x 100
whole

12. Example: % concentration by mass
15 g of salt are added to 100 g of water. What is the percent concentration by mass of salt?

13. Example with ppm:
What is the concentration in ppm, of a solution with 19g Kool Aid dissolved in 100g of water?