Pre-Class Wednesday In a solution, the substance that dissolves other substances is the _________.

Pre-Class Monday Write one example of a catalyst.

Chapter 7 Solutions

What is a solution? A homogeneous mixture All components are evenly mixed (no chunks) Cannot determine what compounds make up the mixture

Solute + Solvent = Solution Solute –A material that is being dissolved –Typically, it is a solid Solvent –A material that dissolves other materials –Typically, it is a liquid –More solvent than solute in any given solution

The process of a solute bonding with a solvent Changing of chemical and physical properties Cannot easily separate the solute from the solvent Increasing the process –Stir (agitate) the mixture –Increase the temperature of the mixture –Break up large clumps of solute

Pre-Class Tuesday Which one of the following increases the dissolving process? a)Lower the temperature b)Add more solvent c)Stirring the mixture d)Add more solute

Connection to Engineering Objective –Working in pairs, find out the secrets behind ink. Materials –Textbook –Computer (Internet) Procedures –Turn to page 228 in textbook. –Read and follow the instructions in the Connection to Engineering section. –Answer questions on your own paper.

Polar Vs Nonpolar Nonpolar compounds are neutral –They have no distinctive charge on any side –Do not dissolve in polar compounds Polar compounds are neutral –They have a distinctive positive and negative side –Do not dissolve in nonpolar compounds “like dissolves like”

Solubility The maximum amount of solute that can be dissolved in a solvent at a given temperature Will change depending on: –Amount of solvent –Temperature of solvent Look at Table 1 on p240

Concentration The actual amount of solute in a solution compared to the amount of solvent Not an exact descriptor –Dilute: low concentration –Concentrated: medium to high concentration –Saturated: cannot dissolve any more solute –Supersaturated: by changing conditions, more solute can be added (temporary)

Particles in Solution Ion: a charged (positive or negative) particle Ionization: the process of making a neutral particle into a charged one (can happen during dissolving) –Electrolyte: a fluid that conducts electricity –Nonelectrolyte: a fluid that does not conduct electricity Dissociation: when a compound separates during dissolving or a reaction

Penny Drops Materials –2 pennies Paper towels –2 pipettes Beakers Procedures –Find the number of drops of water that will fit on a penny. –Find the number of drops of isopropyl alcohol that will fit on a penny. Conclusions –Based on your results, describe the differences between the materials. –How could this information help with handling the liquids? –Give three reasons why your results may be different than other groups.

83 At which temperature is the solubility the same for KBr and NaClO 3 ? 49

Pre-Class Tuesday Write: “Reviewing for test.”

KCl 48 Section II #3, 4, 6, 7