Lecture 0502 Types of Reactions

1. Synthesis [composition] elements  compounds Synthesis of Sodium Chloride

Types of Reactions 2. Decomposition Compound  elements and/or simpler cmpds Decomposition of HgO

3. Single displacement a more reactive element replaces a less reactive element in a compound Types of Reactions Sodium in Water

4. Double displacement (metathesis reaction) solutions of two ionic compounds react to form a solid product (precipitate), or a molecular substance Types of Reactions

Double Displacement Pb(NO 3 ) 2 (aq) + 2 KI(aq)  PbI 2 (s) + 2 KNO 3 (aq) The anions exchange places between cations. Lead (II) Iodide AX + BY  AY + BX

Solubility of Salts in Water 1. Most nitrate salts are soluble 2. Most salts containing the alkali metal ions and the ammonium ion are soluble

Solubility of Salts in Water 3. Most chloride, bromide, and iodide salts are soluble, EXCEPT of salts containing the ions of silver, lead (ll), and mercury (l)

Solubility of Salts in Water 4. Most sulfate salts are soluble, EXCEPT with ions of barium, lead (Il), mercury (ll), and calcium

Solubility of Salts in Water 5. Most hydroxide salts are only slightly soluble. The important soluble hydroxides are NaOH and KOH. Barium, strontium, and calcium hydroxides are marginally soluble

6. Most sulfide, carbonate, chromate, and phosphate salts are only slightly soluble Figure 5.1 in text Pg 48 in TUCEH Solubility of Salts in Water

Types of Reactions 5. Combustion of hydrocarbons hydrocarbon + O 2  CO 2 + H 2 O

Molecular Equations Gives overall reaction stoichiometry, but NOT necessarily the actual forms of reactants & products in solution.

Ionic Equations Represents as ions all reactants and products that are strong electrolytes.

NET Ionic Equations Includes only those solution components undergoing change Spectator ions are not included.

Net Ionic Equations Mg (s) + 2 HCl (aq)  H 2 (g) + MgCl 2 (aq) We really should write… Mg (s) + 2 H Cl -  H 2 (g) + Mg Cl -

Net Ionic Equations Mg (s) + 2 H Cl -  H 2 (g) + Mg Cl - The two Cl - ions are SPECTATOR IONS They do not participate. Could have used any X -

Practice Ch 6-10 In TUCEH