Chemistry Unit 9 & 10

1.Solution

2.Aqueous Solution

1.homogeneous mixture of solute and solvent

2.solution in which water is the solvent


Solute

substance whose particles are dissolved in a solution


Solvent

substance in which the solute dissolves

*universal solvent = water!


Suspension

Mixture (not always a solution) in which particles will eventually settle to the bottom


Like Dissolves Like (polarity)

Polar molecules dissolve polar molecules. Nonpolar molecules dissolve nonpolar molecules. They do no dissolve each other


Concentration

the amount of solute per amount of solvent. To concentrate a solution, either add more solute or reduce amount of solvent that you initially started with (before putting in solute)


Saturated

the solution has dissolved the maximum amount of solute


Unsaturated

solution containing less than saturated amount of solvent


Supersaturated

solution containing more than saturated amount of solvent; the solution cannot dissolve any more of the solute, and the remaining solute is left as a “precipitate”


Factors Effecting Rate of Dissolving

-particle size:the smaller the particle size, the faster it will dissolve -stirring or agitation -amount of solute already in solution:as the saturation point is being reached, the rate of dissolving will slow down -Temperature:certain substances dissolve more readily in warm solvents than in cold solvents


Molarity

measure of the concentration of a solute in a solution

M = mass of solute/liters of solution


Precipitation:

1.Precipitate (ppt)

2.Precipitation Reaction

1.a solid that separates from a solution – either created or left over

2.a reaction that results in the formation of a precipitate


Molecular Equation

a BALANCED chemical equation in which ionic compounds are written as neutral formulas rather than as ions


Ionic Equation

in this type of equation, all substances that are strong electrolytes are represented as ions (only aqueous compounds!)


Spectator Ion

an ion present in solution but doesn’t participate in the reaction (the ion itself will remain the same)


Net Ionic Equation

includes ONLY those solution components undergoing change


Solubility Curves

tells what mass of solute will dissolve in 100g(100mg) of water over a range of temperatures. The lines indicate the concentration of a saturated solution.

-If amount of solute (in grams) is below the line, the solution is unsaturated at that temp.

-If amount of solute is on the line, the solution is saturated at that temp.

-If the amount of solute is above the line, the solution is supersaturated at that temp.

*solutes whose curves move upward with increased temperature are typically solids and solutes whose curves move downward with increased temperature are typically gases


Acid

a compound that produces hydronium/hydroxide ions (H3O+) or hydrogen ions (H+)when dissolved in water properties:sour taste. Acids change color of acid-base indicators (Litmus paper turns red). Some acids react with metals to release hydrogen gas.


1.Arrhenius acid 2.Arrhenius base

1.chemical compound that increases the concentration of hydrogen ions (H+) in solutions

2.substance that increases the concentration of hydroxide ions (OH), in solutions


Base

a compound that produces hydroxide ions(OH) when dissolved in water. Taste bitter. Bases change color of acid-base indicators (Litmus paper turns blue). Dilute aqueous solutions of bases feel slippery.


Bronstead-Lowry Theory

Acid – “proton donor” Base – “proton acceptor” Conjugate Base – compound that remains after acid has given up/donated its proton (-)

Conjugate Acid – compound that forms when base gains/accepts a proton (+)

ex.)NH3 + H2O = NH4+ + OH

NH3=base

H2O=acid

NH4+=conjugate acid

OH=conjugate base


Neutralization

a reaction between an acid and a base (usually strong acid with a strong base). Reaction produces a “salt” and water – salt is a compound formed by replacing hydrogen in an acid by a metal in a base.

Ex.)H3PO4 + Ca(OH)2 = H2O + Ca3(PO4)2…Ca3(PO4)2 is the salt


Binary acid

contains only 2 different elements

ex.)HF – hydrofluoric acid


Oxyacid

acid that is a compound of hydrogen, oxygen, and a third element

ex.)H2(SO4) – sulfuric acid


Monoprotic

“one proton” Releases only one hydrogen ion into solution ex.)HCl – hydrocholric acid


Polyprotic

Releases more than one H+ into solution

ex.)H2(SO4) [diprotic] or H3PO4 [triprotic]


Amphoteric

any species that can react as either an acid or a base ex.)H2O


1.)pH

2.)pOH

3.)pH+pOH

1.)measure of the acidity or basicity of a substance formula: -log[H+]

2.)formula: -log[OH]

3.)pH + pOH = 14


pH scale

goes from 0 to 14; 7 is a base, and 7 is neutral


Naming acids that DO NOT contain oxygen in the Anion:

The acid name comes from the root name of the anion name. The prefix hudro and the suffix -ic are than added to the root name of the anion.

Ex.)HCl, which contains the cation ion hydrogen and the anion chloride is called…hydrochloric acid!


Rules for naming Oxyacids (anions that DO contain the element oxygen)

The acid name comes from the root name of the oxyanion name. Suffixes are used based on the ending of the original name of the oxyanion. If the name of the polyatomic anion ended with -ATE, change it to -IC for the acid

Ex.)HNO3, which contains the polyatomic ion nitrate is called nitric acid If the name of the polyatomic anion ended with -ITE, change it to -OUS in the acid

Ex.)HNO2, which contains the ployatomic ion nitrite is called nitrous acid

*There is no prefix “hydro” in naming oxyacids


Acid-base Indicators

1. Litmus Paper – turns red in acids, blue in bases

2. Phenophthalein – turns orange in acid, colorless in neutral, hot pink in base


Titration

controlled addition and measurement of the amount of solutions of known concentration (standard) required to react completely with a measured amount of a solution of unknown concentration. Used to determine the unknown concentration of a known reactant


Equivalence Point

point at which the 2 solutions used in a titration are present in chemically equivalent amounts – the smallest amount of “titrant” (solution being delivered from burette – normally standard or known conc.) that is sufficient to fully neutralize with the solution being titrated (needs an indicator to turn color at equivalence point – “endpoint”)


Titration Calculations

M1V1 = M2V2

M=molarity

V=volume


Reversible Reaction

chemical reaction in which the products react to reform reactants

Ex.)2HgO = Hg + O2….forward 2Hg + O2 = 2HgO….reversed


Chemical Equilibrium

Rate of forward reaction = rate of reverse reaction. [reactants] and [products] do not change (the brackets mean you’re looking at a concentration of). Appears as though reaction has stopped because it seem like no more products are being produced; however, its just a never ending cycle of reactant turning into products and vice versa. At equilibrium the ration of [reactants] and [products] is constant


Equilibrium Constant (Keq)

the ration of the concentration of proudcts to the concentration of reactants.

Keq = [products]/[reactants]

ie.) 2HgO – 2Hg + O2….[Hg]2[O2]/[HgO]2

*the concentration is raised to the power of coefficients of the substance in the equation


Le Chatelier’s Principle

if a system at equilibrium is subjected to a stress. the equilibrium is shifted in the direction that tends to relieve that stress (or, when a reactant or product is added to a system at equilibrium, the system shifts away from the added component to balance – like a “seesaw” between the reactant and product)


Stress on Systems – Factors that cause “stress”

1.Pressure:an increase in pressure will cause a “shift” to the side with less moles(particles) of gas

Ex.)N2+ 3H2 = 2HN3…the reactant has 4 moles while the product has only 2. An increase in pressure shifts to the side with fewer moles…Inverse: 2NH3 = N2 + 3H2

2.Concentration:an increase in concentration of reactant or product causes a “shift” to the opposite side to “balance change

Ex.)N2+ 3H2 = 2HN3

3.Temperature:addition of heat(endothermic) favors forward reaction; removal of heat(exothermic) favors reverse reaction