Unit 8 Part 2: Acids, Bases, & Salts

​13.1: Acids, Bases, & Salts

​Properties of Acids

• Acid comes from the latin words acidus (tart)

  • Acids tend to have a sour taste

    • most (but not all) are poisonous

  • Acids change the colors of acid-base indicators

  • Acids react with bases to produce salts and water

  • Acids conduct electric current

  • Some acids react with metals and release Hydrogen gas (H₂)

  • Produce Hydronium ions (H₃O⁺)​

Experience Chemistry | Lesson 13.1

Types of Acids

• ​Binary Acids: contain only two different element, Hydrogen and an electronegative element

  • Naming Ru​les

    • The Name begins with the prefix hydro

    • the root of the name follows the name of the second element, with the ending changed to -ic

      • Example: HCl

        • Hydro from hydrogen

        • Chlorine changes to Chloric

        • Hydrochloric Acid

Multiple Choice

Which formula shows hydrofluoric acid

• HF

• HI

• H₂S

• HBr

Properties of Bases (aka Alkalines)

• Bases are also compounds that share unique properties

  • Aqueous Bases taste Bitter,

  • many are caustic (can burn your skin)

  • Bases change the color of acid-base indicators​

  • Dilute aqueous solutions of bases feel slippery

  • Bases react with acids to produce salts and water

  • Bases Conduct Electric Currents

  • Bases react with oils

    • Many Bases are used in cleaning agents

  • Produce Hydroxide ions (OH^-)

What is a Salt?

• Salts: ionic compounds

  • Can be produced when an acid and a base interact with each other

  • when dissolved in solution they are called electrolytes​

    • Can be precipititaed out of solution to a solid

Defining Acids and Bases

• Acids and Bases are very wide categories, and we can divide them up in several ways

  • Arrhenius Model

  • Brø​nsted-Lowry Model

  • Lewis Model

Arrhenius Model of Acids and bases

• First Proposed Model

• Svante Arrhenius (1859-1927): Swedish chemist

  • saw that acids and bases conduct electricity, so they must produce ions in solutions

    • Arrhenius Acid: A compound that increases the concentration of Hydrogen ions, H⁺, in water

      • H⁺ doesn't stay in solution long, joins with oxygen to form H₃O

      ​

Arrhenius Model of Acids and bases

• Types of Arrhenius Acids

  • Monoprotic: only have one hydrogen in them

    • ​HCl, HNO₃

  • Diprotic: Have two hydrogens in them

    • Carbonic Acid H₂CO₃

  • Triprotic: Have three hydrogens in them

    • Phosphoric Acid H₃PO₄

Arrhenius Model of Acids and bases

​

• Arrhenius Base: a substance that releases Hydroxide ions, OH^-, when dissolved in water

  • Has to have an OH in them​

    • Monoprotic Bases: Have one hydroxide ion

    • Diproitic Bases: Have two hydroxide ions

Multiple Choice

What type of substance is Potassium Hydroxide (KOH)?

• Monoprotic Acid

• Monoprotic Base

• Diprotic Acid

• Diprotic Base

Multiple Choice

What type of substance is KOH?

• Monoprotic Acid

• Monoprotic Base

• Diprotic Acid

• Diprotic Base

Multiple Choice

What type of substance is HClO₄?

• Monoprotic Acid

• Monoprotic Base

• Diprotic Acid

• Diprotic Base

Multiple Choice

What type of substance is H₂SO₄?

• Monoprotic Acid

• Monoprotic Base

• Diprotic Acid

• Diprotic Base

Brønsted-Lowry Model of Acids and bases

​

• Arrhenius's model has flaws

  • does not work for all bases

    • Ammonia (NH₃) does not contain Hydroxide, but can react to form hydroxide ions

  • It also does not work for compounds that are solid

• Johannes Brønstead and Thomas Lowry proposed a different definition to solve these problems:

  • An Acid is a Hydrogen-ion donor

  • A base is a Hydrogen-ion acceptor​

Brønsted-Lowry Model of Acids and bases

Brønsted-Lowry Model of Acids and bases

• In the Brønsted-Lowry Model, products of acid and base reactions are called conjugates

  • Conjugate Acid: The ion/molecule formed when a base gains a hydrogen

  • Conjugate Base: The ion/molecule formed when an acid loses a hydrogen ion

  ​

Brønsted-Lowry Model of Acids and bases

• Conjugate acid-base pair: two ions or molecules related by the loss or gain of a hydrogen atom

  • The base gains a hydrogen to become the conjugate Acid

    ​

Lewis Model of Acids and bases

• Model developed by Glibert Lewis

• Uses electron pairs to define acids and bases instead of ion

  • Includes more compounds than Arrhenius or Brønsted-Lowry Models

• Lewis Base: Donates a pair of electrons to form a covalent bond

• Lewis Acid: Accepts a pair of electrons to form a covalent bond

Multiple Choice

Which of the following correctly identifies an acid and its conjugate base?

• HH₄⁺ , OH^-

• H₂O , OH^-

• CaCO_{3 ,}CaCl₂

• HNO₃ , H₂SO₄

Multiple Choice

Which of the following show an acid and its conjugate base pair (in that order)

• H₂SO₄, SO₄^2-

• OH^-, H₂O

• NH₄⁺, H₂O

• H₂CO₃, HCO₃^-

Multiple Choice

The conjugate base of H₂SO₄ is ___.

• H₂SO₃

• HSO₄^-

• H₃SO₄⁺

• SO₄^-2

Multiple Choice

What is the conjugate acid of water?

• $$OH^-$$

• $$H_3O^+$$

• $$H_2O_2$$

• $$HOH$$