thanksgiving gifts from photosynthesis or nature’s chemistry at it’s best
TRANSCRIPT
Thanksgiving Gifts from Photosynthesis ORNature’s Chemistry at It’s Best
Thanksgiving Gifts from Photosynthesis
Have a great
Thanksgiving holiday!
Section 8.2
Other Reactions in Aqueous Solutions
Sections 8.2-8.3
1. identify various types of chemical reactions
2. identify the processes and driving forces behind different types of reactions
3. Write equations for different types of reactions
Learning Goals – I will be able to…
Section 8.2
Other Reactions in Aqueous Solutions
Sections 8.2-8.3
Formation of a SolidPrecipitation, a Double Displacement Reaction
(covered in 8.1)
• General equation: AB + CD AD + CB
• Precipitation reaction
• Double displacement/replacement reaction
Section 8.2
Other Reactions in Aqueous Solutions
Sections 8.2-8.3
Formation of Water: Acids and Bases (not in notes):A different type of double replacement reaction
A strong acid is one in which virtually every molecule dissociates (ionizes) in water to an H+ ion and an anion.
Section 8.2
Other Reactions in Aqueous Solutions
Sections 8.2-8.3
A strong base is a metal hydroxide that is completely soluble in water, giving separate OH ions and cations.
Formation of Water: Acids and Bases (not in notes)
– Most common NaOH, KOH
Section 8.2
Other Reactions in Aqueous Solutions
Sections 8.2-8.3
Formation of Water: Acid-Base Reaction, a Double Replacement Reaction
(not in notes) • The products of the reaction of a strong acid and a
strong base are water and a salt. • Net ionic equation
H+(aq) + OH−(aq) H2O(l)
• Reaction of H+ and OH− is calledan acid-base reaction.
H+ acidic ion
OH− basic ion• The other anion/cation pair forms a
Salt (Ionic compound)
* NOTICE THAT IF THE PROPER
AMOUNTS OF ACID AND BASE ARE
MIXED THE PH OF THE SOLUTION WILL BECOME
NEUTRAL. *
Section 8.2
Other Reactions in Aqueous Solutions
Sections 8.2-8.3
• Acids and bases are both ionic compounds strong acids/bases are strong electrolytes.
• Acids produce H+ ions in water.• Bases produce OH- ions in water.• Water is a very stable compound strong
tendency for reaction to happen.
Acid + Base Water + Salt
HCl(aq) + NaOH(aq) H2O(l) + NaCl(aq)
Net Ionic Equation: H+(aq) + OH−(aq) H2O(l)
Formation of Water: Acid-Base Reaction, a Double Replacement Reaction
(notes summary)
Section 8.2
Other Reactions in Aqueous Solutions
Sections 8.2-8.3
Transfer of Electrons -- Reactions of Metals with Nonmetals (Oxidation-Reduction)
Reactions between metals and nonmetals involve a transfer of electrons from the metal to the nonmetal.
Oxidation–reduction reaction (redox)
Section 8.2
Other Reactions in Aqueous Solutions
Sections 8.2-8.3
Transfer of Electrons:Oxidation-Reduction Reactions
• A metal and a nonmetal combine to form an ionic compound. Ex.:
2Na(s) + Cl2(g) 2NaCl(s)
• Electron transfer:– sodium is “oxidized” loses one electron– chlorine is “reduced” gains one electron
Section 8.2
Other Reactions in Aqueous Solutions
Sections 8.2-8.3
Single Replacement – One Ion Replaced
• Driving force:
– Transfer of electrons
General equation: A + BC B + AC
Section 8.2
Other Reactions in Aqueous Solutions
Sections 8.2-8.3
Single Replacement Reaction – One Ion Replaced (another example)• Driving forces:
– Transfer of electrons– Formation of a Gas
Section 8.2
Other Reactions in Aqueous Solutions
Sections 8.2-8.3
Involve oxygen & produce a flame (energy released rapidly)
CH4(g) + 2O2(g) CO2(g) + 2H2O(g)
• Combustion Reactions
Types of Oxidation-Reduction Reactions (Redox)
A compound forms from simpler materials
C(s) + O2(g) CO2(g)
• Synthesis (Combination) Reactions
A compound is broken down into simpler substances
2H2O(l) 2H2(g) + O2(g)
• Decomposition Reactions
• Single Replacement (seen before) – new ion forms
Section 8.2
Other Reactions in Aqueous Solutions
Sections 8.2-8.3
Ways to Classify Reactions (notes summary)
• Precipitation – a solid forms• Double Replacement (Displacement) – two ions
exchanged/replacedEx.: acid-base, precipitation
• Single Replacement – one ion replaced• Combustion – energy is released, flame; oxygen is
a reactant• Synthesis – reactants combine to form product(s)• Decomposition – reactant breaks down into
products
* Refer to reaction sheet to see examples. *
*REDOX REACTIONS*