Module 13 lesson 1 notes
- 2. Classifying Reactions • There are millions of substances and many different possible reactions • There are only a few general reaction types • Just like there are ways to identify the names of compounds, there are ways to identify types of chemical reactions and predict the products
- 3. Synthesis Reactions • Combine substances • Reaction of at least 2 reactants combine to form a product • A + B -- AB • Always join substances so the product is more complex than the reactant
- 4. Decomposition Reactions • Break substances apart • Reaction in which one compound reaks into at least 2 products • AB -- A + B • 2H2O -- 2H2 + O2
- 5. Combustion Reactions • Use oxygen as a reactant • Oxygen is a reactant in EVERY combustion reaction
- 6. Single Displacement Reactions • Elements trade places • XA + B -- BA + X • Usually, a more reactive element takes the place of a less reactive element
- 7. Double-Displacement Reaction • Reaction in which a gas, solid precipitate, or a molecular compound is formed • Ions appear to be exchanged between compounds • AX + BY -- AY + BX
- 8. Electrons and Chemical Reactions • Classes of reactions (Synthesis, Decomposition, Combustion, Single- Displacement, Double Displacement) used by early chemist before atom was understood • Today, reactions can be classified by understanding the transfer of electrons
- 9. Redox Reactions • Reduction/Oxidation Reaction • A reaction that occurs when electrons are transferred from one reactant to another • Substances that accept electrons are reduced (gain e- reduces + charge) • Substances that give up electrons are oxidized
- 10. Summary • Synthesis reactions make larger molecules • Decomposition breaks compounds apart • In combustion reactions, substances react with oxygen • Elements appear to trade places in single-displacement reactions
- 11. Summary cont... • In double-displacement reactions, ions appear to move between compounds, resulting in a solid that settles out in solution, a gas that bubbles out of a solution, and/or a molecular substance • In redox reactions, electrons are transfer from one substance to another
- 12. Question 1 • Classify each of the following reactions by type – A) S8 + 8O2 -- 8SO2 + heat – B) 6CO2 + 6H2O -- C6H12O6 + 6O2 – C) 2NaHCO3 -- Na2CO3 + H2O + CO2 – D) Zn + 2HCl -- ZnCl2 + H2
- 13. Question 2 • Identify which element is oxidized and which element is reduced in the following reaction – Zn + CuSO4 -- ZnSO4 + Cu
- 14. Question 3 • Compare and contrast single- displacement and double-displacement reactions based on the number of reactants. • Use the terms compound, atom, element, and ion.