Group+4+Period+2

=**Welcome To Group 4's Page!**=

-Jessie, Frances, Harriet, and Caroline C.-
Click here to visit the Homework page for homework assignments: [|Middle School Homework]

Click here to visit the Science Study Buddies website for games, vocabulary review, and practice tests: [|Science Study Buddies]

Click here to visit the White Team Period 2 class blogs: [|White Team Blogs]

Click here to visit the Blue Team Period 2 class blogs: [|Blue Team Blogs]

Brainstorming:
 * notes
 * labs
 * helpful hints
 * practice problems

Don't forget to study for...

 * 1) On Wednesday, February 27- quiz on sections 8.1 and 8.2


 * It involves the vocabulary, notes, and formulas


 * 1) On Wednesday, March 5- quiz on sections 8.3 and 8.4
 * 2) On Thursday, March 6- TEST on Chapter 8

//Vocabulary://
Solute- a substance whose particles are dissolved in a solution Solvent- the substance in which the solute dissolves Dissociation- the process in which an ionic compound separates into ions as it dissolves Dispersion- the process in which substances break into small pieces that spread throughout the water Ionization- the process in which neutral molecules gain or lose electrons

//Notes://
Solution- a homogenous mixture of two or more substances; it can be a solid, a liquid, or a gas; Parts of a solution: Note: its state is named for the solvent because the solvent is what you see in a solution Example: Sugar water is a solution, and it is a liquid because water, the solvent, is a liquid
 * Solute- the substance that is dissolved in a solution; it’s the smaller part
 * Solvent- the substance in which the solute dissolves; it’s the larger part

Dissolving- there are three ways in which substances dissolve Polar- the negatively charged ions are attracted to the positively charged ions Note: Dissociation involves ionic compounds (which neither dispersion nor ionization does) so therefore there are charges involved
 * Dissociation- the process in which an ionic compound separates into ions as it dissolves; involves ionic compounds
 * Dispersion- the process in which substances break into small pieces that spread throughout the water


 * Example: sugar disperses in water, but salt does not because salt is an ionic compound while sugar is a molecular compound


 * Hint: To review ionic & molecular compounds, see Chapter 6


 * Note: Both dissociation and dispersion are physical changes because they do not change the composition.

The solute and solvent particles have reacted to form, new substances, which is why this is a chemical change (unlike dissociation and dispersion) because it changes the composition of the substances Example: H2O + HCL yields H30 (+) + Cl (-) (HCL is hydrochloric acid and H30 (+) is hydronium ion)
 * Ionization- the process in which neutral molecules gain or lose electrons, becoming ions
 * Note: Both dispersion and ionization involve molecular compounds, which includes atoms not ions (unlike dissociation)

Properties of Liquid Solutions: Example: NaCl in water vs. salt in solid form (NaCl in water is more conductive than salt in solid form because of the negatively charged ions, which are conductive) Solute particles affect (raise or lower) the freezing point and boiling points of the solvent (Salt affects freezing and boiling points more than sugar does because it is an ionic compound, while sugar is a molecular compound)
 * Physical Properties: conductivity, freezing point, and boiling point of a solution differ from properties of the solution’s solute and solvent

Heat of Solution: when solutions are formed, energy is either released or absorbed Example- a cold pack
 * · Solution formation can be either:
 * 1) Endothermic- when heat is given off when the solution is formed
 * 2) Exothermic- when heat is absorbed when the solution is formed, and therefore feels cold

Three Factors that affect rates of dissolving: They are direct proportions because during the forming of a solution, the particles of the solute and the solvent collide; the more collisions, the faster the substances will dissolve.
 * Stirring
 * Surface area
 * Temperature

//Vocabulary://
Solubility- the maximum amount of a solute that dissolves in a given amount of solvent at a constant temperature Saturated Solution- a solution that contains as much solute as the solvent can hold at a given temperature Unsaturated Solution- a solution that has less than the maximum amount of solute that can be dissolved Supersaturated Solution- a solution that contains more solute than it can normally hold at a given temperature Concentration- the amount of solute dissolved in a specified amount of solution Molarity- the number of moles of a solute dissolved per liter of solution

Solubility- the maximum amount of a solute that dissolves in a given amount of solvent at a constant temperature The higher the number, the more soluble Example: 36.8 grams/ 100 mL at 32°C vs. 158.2 grams/ 100 mL at 32°C; obviously the first one has the higher solubility Once saturated, no more solute will dissolve Factors that affect solubility: If one (either the solute or the solvent) is polar and one (the solute or the solvent) is nonpolar, they don’t dissolve Like dissolves with like: Polar dissolves with polar, and nonpolar dissolves with nonpolar. Concentration- the amount of solute dissolved in a specified amount of solution Can be expressed as: __Volume of solute__ x 100 Volume of solution __Mass of solute__ x 100 Mass of solution __Moles of solute__ Liters of solution
 * Saturated Solution- a solution that contains as much solute as the solvent can hold at a given temperature
 * Unsaturated Solution- a solution that has less than the maximum amount of solute that can be dissolved for that temperature
 * Supersaturated Solution- a solution that contains more solute than it can normally hold at a given temperature; very unstable
 * Polarity of the solvent
 * Temperature
 * Pressure
 * Percent by volume
 * Percent by mass
 * Molarity- the number of moles of a solute dissolved per liter of solution; the symbol for molarity is M