5.2.2 Ionic Equations

• In a chemical reaction, the starting substances are called reactants
• What are reactants in a chemical reaction?

  Starting substances consumed
• Products are the new substances formed in a chemical reaction
• In the reaction 2Na + 2HCl → 2NaCl + H2, the reactants are Na and HCl
• What are the products in the reaction 2Na + 2HCl → 2NaCl + H2?

  NaCl and H2
• Balancing a chemical equation requires adjusting the coefficients to ensure the same number of atoms of each element on both sides.
• The balanced equation for Na + HCl → NaCl + H2 is 2Na + 2HCl → 2NaCl + H2
• What must be verified after balancing a chemical equation?

  Atom balance
• When ionic compounds dissolve in water, they dissociate into positive and negative
• Why do ionic compounds dissociate in water?

  Polar water molecules break ionic bonds
• Covalent compounds like water do not dissociate in water.
• What type of bonding is present in covalent compounds that prevents dissociation?

  Covalent bonds
• Match the compound type with its property:

  Ionic compounds ↔️ Dissociate into ions

  Covalent compounds ↔️ Do not dissociate
• Why do ionic compounds dissociate into ions when dissolved in water?

  Polar water molecules break bonds
• Covalent compounds like water dissociate into ions when dissolved in water.

  False
• Ionic compounds dissociate into ions
• What type of bonds hold ionic compounds together?

  Ionic bonds
• Ionic compounds are often soluble in water
• Do covalent compounds conduct electricity when dissolved in water?

  No
• Ionic compounds like NaCl dissociate into positive and negative ions when dissolved in water.
• In a chemical reaction, the starting substances are called reactants
• Match the component with its definition:

  Reactants ↔️ Starting substances in a reaction

  Products ↔️ Substances formed after the reaction
• Steps to balance a chemical equation

  1️⃣ Identify reactants and products

  2️⃣ Count atoms

  3️⃣ Balance atoms using coefficients

  4️⃣ Verify balance
• A coefficient in a chemical equation changes the number of atoms of a specific element.
• A subscript in a chemical formula indicates the number of atoms of that element
• Balance the equation: C₂H₆ + O₂ → CO₂ + H₂O

  2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O
• Covalent bonds are stronger than ionic bonds in water.
• Write the equation for the dissociation of NaCl in water.

  NaCl(s) → Na+(aq) + Cl-(aq)
• Spectator ions are present in a reaction but do not undergo chemical change
• Spectator ions react during a chemical reaction.

  False
• Identify the spectator ions in the reaction: NaCl(aq) + AgNO3(aq) → AgCl(s) + NaNO3(aq)

  Na+ and NO3-
• What is the definition of reactive ions?

  Ions that undergo change
• Spectator ions are present in a reaction but do not participate in the change itself.
• Spectator ions react during a chemical reaction.

  False
• What happens to spectator ions during a reaction?

  They remain unchanged
• Spectator ions are often referred to as chemical reaction spectators.
• Na+ and NO3- are spectator ions in the reaction NaCl(aq) + AgNO3(aq) → AgCl(s) + NaNO3(aq).
• What is the first step in writing a net ionic equation?

  Identify reactants and products
• Steps to write a net ionic equation

  1️⃣ Identify reactants and products

  2️⃣ Determine spectator and reactive ions

  3️⃣ Remove spectator ions
• What is the net ionic equation for the reaction between NaCl and AgNO3?

  Cl-(aq) + Ag+(aq) → AgCl(s)