Chemistry Chapter on Acids and Bases

Acids

• Acids have a pH value below 7.
• Acids have a sour taste (when edible) and are corrosive.
• Acids neutralize bases, forming salt and water.
• Acids release positively charged hydrogen ions (H+) when dissolved in water, making the solution acidic.
• Example of acid dissociation: Hydrochloric acid (HCl) dissociates into H+ and Cl- ions when dissolved in water.

Bases

• Bases form hydroxide (OH-) ions.
• Strong bases dissociate almost completely in water, releasing OH- ions.
• Example of strong bases: Sodium hydroxide (NaOH) and Potassium hydroxide (KOH).
• Weak bases dissociate partially in water, producing OH- ions.
• Example of weak bases: Lithium hydroxide (LiOH) and Zinc hydroxide (Zn(OH)2).

Typical Reactions of Acids

• Acids react with metals above hydrogen in the reactivity series.
• Reaction of acids with metals forms salt and hydrogen gas.
• The salt formed depends on the anion in the acid.

Criss Cross Method

• Used to write chemical formulas of ionic compounds.
• Follows a step-by-step process to determine the subscripts for each element.
• Example: Sodium (Na) with a +1 charge and Chloride (Cl) with a -1 charge, using the criss-cross method results in the formula NaCl.

Types of Salts

• Acidic Salts: Formed by partial neutralization of a diprotic or polyprotic acid.
• Basic (or Alkali) Salts: Formed by partial neutralization of a weak acid by a strong base.
• Double Salts: Contain multiple cations or anions.
• Mixed Salts: Contain a fixed proportion of two salts, often with a shared cation or anion.

Physical Properties of Salts

• Compound Name: A common name, often reflecting the constituent ions or source.
• Molecular Formula: Shows the types and numbers of atoms in a molecule.
• Molecular Mass: The mass of one mole of a substance in grams per mole (g/mol).
  • Example: Molecular Mass for NaCl is calculated from the atomic masses of sodium and chlorine.
• Color: Pure salts are colorless, but natural salts can have color variations due to impurities.
• Appearance: Solid salts, such as sodium chloride, have a translucent appearance.

Polarity of Molecules

• Determines how substances interact with each other.
• Polar molecules have uneven charge distribution, giving them distinct positive and negative ends.
• Nonpolar molecules have even charge distribution and no distinct charged ends.
• Polarity impacts solubility, boiling points, and chemical reactions.

Molecular Mass

• The total mass of all atoms in a molecule.
• Calculated by adding the atomic masses of each atom in the molecule.
• Measured in atomic mass units (amu or u).

Mole

• The amount of substance containing 6.02214076 × 1023 elementary entities (atoms, molecules, ions).
• Called Avogadro's constant (NA).

Molar Mass

• The mass of one mole of a substance, expressed in grams per mole (g/mol).
• Represents the mass of 6.022 × 1023 molecules or atoms of that substance.

Static Electricity

• Occurs when two or more bodies come into contact and separate, resulting in a charge imbalance.
• Involves the transfer of electrons between materials.
• Static electricity is most likely to occur when one material is an insulator.
• Examples: Walking across a carpet, rubbing a balloon on your hair.

Lightning

• A large-scale example of static discharge.
• Charge imbalance in clouds is neutralized by a massive electrical discharge (spark).

Lightning conductor

• A metal rod placed on top of a building to protect it from lightning strikes.
• The conductor is struck by lightning, diverting the charge away from the building.

Small-Scale Mutations

• Involve changes to the DNA sequence, affecting single nucleotides or codons.

Silent Mutations

• A nucleotide substitution that does not change the amino acid sequence.

Missense Mutations

• A nucleotide substitution that results in a different amino acid, potentially altering the protein's function.

Nonsense Mutations

• A nucleotide substitution that creates a stop codon, truncating the protein and usually leading to loss of function.

Large-Scale Mutations

• Affect entire portions of chromosomes.
• Can involve single chromosomes or multiple chromosomes.

Inversion

• A complete reversal of one or more genes within a chromosome.

Insertion

• One or more genes are removed from one chromosome and inserted into another.

Translocation

• Chromosomes swap one or more genes with another chromosome.

This quiz covers the essential properties and reactions of acids and bases, including their pH values, taste, and chemical behavior. Explore key concepts like acid dissociation and the criss cross method for writing chemical formulas. Test your knowledge on strong and weak bases as well as typical reactions of acids with metals.