General Chemistry Study Guide: Solutions, Acids & Bases, Hydrocarbons, and Functional Groups

Chapter 9: Solutions

Key Terms and Concepts

• Solution: A homogeneous mixture of two or more substances.

• Solute: The substance present in a lesser amount; it is dissolved in the solvent.

• Solvent: The substance present in a greater amount; it dissolves the solute.

• Concentrated: A solution containing a large amount of solute relative to solvent.

• Dilute: A solution containing a small amount of solute relative to solvent.

• Saturated: A solution that contains the maximum amount of solute that can dissolve at a given temperature.

• Unsaturated: A solution that contains less solute than the maximum amount that can dissolve at a given temperature.

Solubility Rules

• Solubility rules help predict whether an ionic compound will dissolve in water.

• Common rules include: All nitrates (NO3-) and alkali metal salts are soluble; most chlorides, bromides, and iodides are soluble except those of Ag+, Pb2+, and Hg22+.

• Refer to lecture notes for a complete list.

Concentration Expressions

• Percent by mass (%(m/m)): $\% (m/m) = \frac{\text{mass of solute}}{\text{mass of solution}} \times 100$

• Percent by volume (%(v/v)): $\% (v/v) = \frac{\text{volume of solute}}{\text{volume of solution}} \times 100$

• Mass-volume percent (%(m/v)): $\% (m/v) = \frac{\text{mass of solute (g)}}{\text{volume of solution (mL)}} \times 100$

• Each concentration can be used as a conversion factor in calculations.

Molarity (M)

• Molarity: $M = \frac{\text{moles of solute}}{\text{liters of solution}}$

• Used to relate the amount of solute to the volume of solution.

Dilution Calculations

• When diluting solutions: $M_1V_1 = M_2V_2$

• Can be applied to other concentration units as well.

Milliequivalents (mEq)

• Used to express ion concentrations, especially in biological contexts.

• $\text{mEq} = \text{mmol} \times \text{charge}$

Electrolytes

• Strong electrolytes: Dissociate completely in water (e.g., NaCl).

• Weak electrolytes: Partially dissociate (e.g., acetic acid).

• Non-electrolytes: Do not dissociate (e.g., sugar).

Osmosis and Dialysis

• Osmosis: The movement of solvent through a semi-permeable membrane from low to high solute concentration.

• Dialysis: The separation of small solute particles from larger ones through a semi-permeable membrane.

Red Blood Cells in Solutions

• Isotonic: No net movement of water; cell retains shape.

• Hypertonic: Water leaves the cell; cell shrinks (crenation).

• Hypotonic: Water enters the cell; cell swells and may burst (hemolysis).

Osmotic Pressure Equivalents

• Glucose: 5% (m/v) solution is isotonic with red blood cells.

• NaCl: 0.9% (m/v) solution is isotonic with red blood cells.

Chapter 10: Acids, Bases, and Salts

Definitions and Examples

• Arrhenius acid: Produces H+ in water (e.g., HCl).

• Arrhenius base: Produces OH- in water (e.g., NaOH).

• Brønsted-Lowry acid: Proton donor.

• Brønsted-Lowry base: Proton acceptor.

• Hydronium ion (H3O+): The actual form of the proton in aqueous solution.

Strong and Weak Acids

• Strong acids: Completely ionize in water.

• Common strong acids: HCl, HBr, HNO3, H2SO4

• Weak acids: Partially ionize in water.

• Common weak acids: H3PO4, H2CO3, CH3COOH

Strong and Weak Bases

• Strong bases: Completely dissociate in water (e.g., NaOH, KOH).

• Weak bases: Partially dissociate (e.g., NH3).

Neutralization and Conjugate Pairs

• In a neutralization reaction, an acid reacts with a base to form water and a salt.

• Conjugate acid-base pairs differ by one proton.

Calculations Involving Acids and Bases

• Given molarity of a strong acid, $[H^+] =$ molarity of acid.

• Given molarity of a strong base, $[OH^-] =$ molarity of base.

• Relationship: $[H^+][OH^-] = 1 \times 10^{-14}$

• $pH = -\log [H^+]$

• $pOH = -\log [OH^-]$

• $pH + pOH = 14$

Buffers

• Buffer: A solution that resists changes in pH when small amounts of acid or base are added.

• Typically composed of a weak acid and its conjugate base, or a weak base and its conjugate acid.

Le Chatelier’s Principle

• If a system at equilibrium is disturbed, it will shift to counteract the disturbance.

Chapter 11: Hydrocarbons

Organic Chemistry and Hydrocarbons

• Organic chemistry: The study of carbon-containing compounds.

• Hydrocarbons: Compounds containing only carbon and hydrogen.

• Organic compounds typically contain C-H bonds; inorganic compounds do not.

Drawing and Naming Hydrocarbons

• Hydrocarbons can be represented as expanded, condensed, or skeletal (line) structures.

• Each carbon forms four bonds; hydrogen forms one bond.

• Straight-chain alkanes (CnH2n+2): methane, ethane, propane, butane, pentane, hexane, heptane, octane.

Intermolecular Forces

• Hydrocarbons exhibit London dispersion forces (weakest type of intermolecular force).

Alkyl Groups

• Methyl (–CH3), ethyl (–C2H5), propyl (–C3H7), isopropyl (–CH(CH3)2).

Isomerism

• Isomers have the same molecular formula but different structures.

• Structural isomers differ in the connectivity of atoms.

Naming Alkanes and Cycloalkanes (IUPAC Rules)

• Identify the longest carbon chain as the parent hydrocarbon.

• Number the chain to give substituents the lowest possible numbers.

• Name and number substituents as prefixes.

Physical Properties

• Alkanes and cycloalkanes are nonpolar, insoluble in water, and have low boiling points compared to polar compounds.

Chemical Reactions

• Combustion: $\text{Alkane} + O_2 \rightarrow CO_2 + H_2O$

• Halogenation: Replacement of H by halogen (e.g., Cl2 or Br2).

Alkenes, Alkynes, and Aromatics

• Alkenes: Contain C=C double bonds; alkynes: Contain C≡C triple bonds.

• Cis/trans isomerism possible in alkenes if each carbon of the double bond has two different groups.

• Benzene derivatives use ortho (1,2-), meta (1,3-), and para (1,4-) designations for disubstitution.

• Phenyl group: –C6H5

• Toluene: Methylbenzene (C6H5CH3).

Addition Reactions of Alkenes and Alkynes

• Addition of H2, halogens (Cl2, Br2), acids (HCl, HBr), and water.

• Markovnikov's Rule: In addition of HX to an alkene, H attaches to the carbon with more hydrogens.

Chapter 12: Alcohols, Thiols, Ethers, Aldehydes, and Ketones

Functional Groups

• Alcohol: –OH group attached to a saturated carbon.

• Phenol: –OH group attached to a benzene ring.

• Ether: R–O–R'

• Amine: R–NH2, R2NH, or R3N

• Thiol: –SH group

• Disulfide: R–S–S–R'

Naming Organic Molecules

• Halogenated hydrocarbons: Prefix the halogen name to the parent hydrocarbon (e.g., chloromethane).

• Alcohols: Replace -e with -ol (e.g., ethanol).

• Phenols: Use 'phenol' as the parent name.

• Ethers: Common names only (e.g., diethyl ether).

Polarity and Solubility

• Alcohols and ethers are generally polar; small alcohols are soluble in water.

• Hydrocarbons and large ethers are nonpolar and insoluble in water.

Classification of Alcohols

• Primary (1°): –OH attached to a carbon bonded to one other carbon.

• Secondary (2°): –OH attached to a carbon bonded to two other carbons.

• Tertiary (3°): –OH attached to a carbon bonded to three other carbons.

Reactions of Alcohols and Thiols

• Oxidation of alcohols: Primary alcohols → aldehydes → carboxylic acids; secondary alcohols → ketones; tertiary alcohols: no reaction.

• Dehydration of alcohols: Produces alkenes and water.

• Oxidation of thiols: Forms disulfides.

• Reduction of disulfides: Forms thiols.

Carbonyl Compounds

• Aldehyde: R–CHO

• Ketone: R–CO–R'

• Common names: formaldehyde (methanal), benzaldehyde, acetic acid (ethanoic acid), benzoic acid, acetone (propanone).

Reactions of Aldehydes and Ketones

• Oxidation of aldehydes: With Benedict’s reagent, aldehydes are oxidized to carboxylic acids.

• Reduction: Aldehydes and ketones are reduced to alcohols; carboxylic acids are reduced to primary alcohols.

• Addition of alcohols: Aldehydes + alcohol → hemiacetal → acetal; ketones + alcohol → hemiketal → ketal.

Hemiacetals, Acetals, Hemiketals, Ketals

• Hemiacetal: Formed from aldehyde + alcohol (one –OR and one –OH on the same carbon).

• Acetal: Formed from hemiacetal + alcohol (two –OR groups on the same carbon).

• Hemiketal: Formed from ketone + alcohol (one –OR and one –OH on the same carbon).

• Ketal: Formed from hemiketal + alcohol (two –OR groups on the same carbon).

Reference Table: Isotonic Solutions for Red Blood Cells

Solute	Concentration (% m/v)
Glucose	5%
NaCl	0.9%

Reference Equations

• $[H^+][OH^-] = 1 \times 10^{-14}$

• $pH = -\log [H^+]$

• $pOH = -\log [OH^-]$

• $pH + pOH = 14$

Additional info: This guide summarizes the skills and concepts required for Exam Three in a General Chemistry course, covering solutions, acids and bases, hydrocarbons, and functional groups. For detailed mechanisms and more examples, refer to your textbook and lecture notes.