Review Chapter 8 & 9:

General, Organic, & Biological ChemistryJanice Gorzynski Smith

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Chapter 8 & 9 Concepts

Identify the solvent and solute in a solution Like dissolves like, predict which molecules will form solutions Predict the effect of temperature or pressure on a solution Perform concentration calculations & conversions Perform dilution calculations Predict relative changes in colligative properties between multiple

solutions Understand osmotic pressure & how your kidney’s work. Identify an acid/base reaction, the acid, base, conjugate acid/base Caculate Ka, Kb

Use Kw to determine concentration of H3O+ or OH-

Discuss how water acts as both an acid and a base Perform titration calculations Communicate how a buffer prevents large pH changes

CH 8 Equations & Conversions

Molarity = moles of solute (mol)

V of solution (L)

M1V1 = M2V2

CH 9 Equations & Conversions

Ka =[H3O+][ ]A −

[HA]

Kb = [OH- ][BH+][ B]

Kw = [H3O+][OH−] = 1.0 x 10−14

pH = -log[H3O+]

•Acidic solution: pH < 7 [H3O+] > 1 x 10−7

•Basic solution: pH > 7 [H3O+] < 1 x 10−7

•Neutral solution: pH = 7 [H3O+] = 1 x 10−7

Solutions, Solubility, & Concentration

1. The solute is the substance present in a lesser amount.

2. The solvent is the substance present in a larger amount.

Solubility is the amount of solute that dissolves in a given amount of solvent. REMEMBER: LIKE DISSOLVES LIKE.

In aqueous or liquid phase solutions solubility increases with increasing temperature Gases dissolved in liquids increase solubility with decreasing temperature and increasing pressure

Communicate how much of a solute is dissolved in a solvent using concentration:

% w/v % v/v % mass / mass ppm Molarity initial values final values

M1V1 = M2V2

Dilution: Adding more solvent to the initial solution. The number of moles solute DOES NOT CHANGE.

Colligative PropertiesColligative properties are properties of a solution that depend on the

concentration of the solute but not its identity.

One mole of any nonvolatile solute raises the boiling point of 1 kg of H2O the same amount, 0.51 oC.

One mole of any nonvolatile solute lowers the freezing point of 1 kg of H2O by the same amount,1.86 oC.

Apply pressure to reverse osmosis. This is how our

kidneys filter blood

Reverse Osmosis

Acids / Bases•A Brønsted–Lowry acid is a proton (H+) donor.

•A Brønsted–Lowry base is a proton (H+) acceptor.

H A + B A − H B++

gain of H+

acid base conjugatebase

conjugateacid

loss of H+

H O H

H2O as a base

add H+

H O H

H +

conjugate acidH2O as an acid

H O−

Conjugate base

remove H+

Strong:

Weak:

Kw = [H3O+][OH−]

Acid / Base Equilibrium & pH

H3O+(aq) + (aq) HA(g) + H2O(l) A −

Ka =[H3O+][ ]A −

[HA]

pH = -log[H3O+]

OH- (aq) + BH+ (aq) B (g) + H2O(l)

Kb = [OH- ][BH+][ B]

Base dissociationconstant

acid dissociationconstant

Low pH (0 ~ 7)[H3O+] high

Acidic Conditions

High pH (7 ~ 14)[H3O+] low

Basic Conditions

Common Acid / Base Reactions

Neutralization reaction: An acid-base reaction that produces a salt and water.

H+(aq) + OH− (aq) H—OH(l)

H+(aq) + HCO3−(aq)

H2O(l) + CO2(g)

H2CO3(aq)

A bicarbonate base, HCO3−, reacts with one H+ to form carbonic acid, H2CO3.

A carbonate base, CO32–, reacts with two H+ to form carbonic acid, H2CO3.

2 H+(aq) + CO32–(aq)

H2O(l) + CO2(g)

H2CO3(aq)

Titration

AH + B A- + BH+

Acid + Base Conjugate Base + Conjugate Acid

Moles ofbase

Volume ofacid

mole–moleconversion

factor

M (mol/L)conversion

factor

Moles ofacid

Volume of base

M (mol/L)conversion

factor[1]

[2]

[3]

Buffers

[ ]A −

[HA]=[H3O+] xKapH of buffer = -log[H3O+] where