2.  A mixture is 2 or more substances that are combined together that can be separated by physical means (not chemically bonded together)  Heterogeneous mixtures – unevenly mixed mixtures, “different” composition throughout  Homogeneous mixtures– evenly mixed mixtures, “same” composition throughout

3.  Which type of mixture are solutions?  Homogenous mixtures  Solutions have the same composition, color, and density throughout them  We call solutions the “best mixed mixtures”  If a solution is made from a substance dissolved in water, it is called an aqueous solution

4.  To create a solution, one substance must dissolve in another substance  Solute – the substance being dissolved When solids or gases are dissolved in liquids, they are considered to be the solutes  Solvent – the substance that does the dissolving When a liquid dissolves another liquid, the liquid that has the largest amount is considered to be the solvent As a general rule of thumb, there is LESS solute and MORE solvent in a solution

5.  Solutions do not always involve a solid or gas dissolving in a liquid  Solid dissolved in solid i.e. Alloys - brass (Melted metal solute mixed with melted metal solvent and cooled)  Gas dissolved in gas i.e. air (78% nitrogen, 21% oxygen, 1% other gases)  Liquids dissolved in gas i.e. clouds  Gas dissolved in solid i.e. marshmallows

6.  For each example, identify the solute and the solvent: Kool-Aid Solute: _____________________ Solvent: _____________________ Sterling Silver (92.5% silver, 7.5% copper) Solute: _____________________ Solvent: _____________________ Styrofoam Solute: _____________________ Solvent: _____________________ Mountain Dew Solute: _____________________ Solvent: _____________________ sugar/ Kool-Aid powder water copper silver air (gas) foam (solid) sugar, carbon dioxide (gas) water

7.  1. Moving solvent molecules cluster around the solute  They are attracted to each other because they have opposite charges (like a magnet)  2. The solvent molecules pull the solute molecules into the solution  3. The solvent and solute molecules spread out to form a homogeneous mixture  Dissolving Animation Dissolving Animation

8.  What can you do to increase the rate at which solutes dissolve in solvents?  Stir it! By stirring, you are bringing more solvent in contact with the solutes, which cause the particles to dissolve more quickly  Decrease crystal size If you make larger solutes smaller, you are increasing the surface area of the crystals which allows the solvent to surround it more easily  Increase temperature Increasing the temperature speeds up the movement of the particles which causes more of the solvent particles to bump into the solute particles Review Song: http://www.youtube.com/w atch?v=3G472AA3SEs