Presentation on theme: "Chapter 4. Definitions Bronsted - acids are proton donors, bases are proton acceptors Arrhenius – acids produce H + ions in water and bases produce."— Presentation transcript:
Definitions Bronsted - acids are proton donors, bases are proton acceptors Arrhenius – acids produce H + ions in water and bases produce OH - ions in solution Net ionic equation for acid-base reactions H + (aq) + OH - (aq) H 2 O (l) The hydroxide ion can be assumed to completely react with even a weak acid in solution.
Stoichiometry Calculations for Acid-Base Reactions 1. List the species present in the combined solution before any reaction occurs. 2. Write the balanced net ionic equation for this reaction 3. Calculate the moles of reactants (may need to use volume and molarity) 4. Determine LR if appropriate 5. Calculate moles of the required species 6. Convert to grams or volume of solution as required in problem
Acid – Base Titrations Vocabulary 1. Titrant – solution of known concentration 2. Analyte – solution of unknown concentration 3. Equivalence point – point at which the amount of titrant added to analyte results in perfect neutralization 4. Indicator – a substance added at the beginning of the titration that changes color at the equivalence point 5. Endpoint – the point at which the indicator changes color
Acid – Base Titrations Requirements for a successful titration 1. The exact reaction between titrant and analyte must be known 2. The reaction must proceed rapidly 3. The equivalence point must be marked accurately (select the appropriate indicator) 4. The volume of titrant required to reach the equivalence point must be known accurately 5. For acid-base titrations, the titrant should be a strong acid or a strong base
Electron Transfer (OIL RIG) Oxidation Is a Loss of electrons Reduction Is a Gain of electrons Examples of redox reactions Photosynthesis Combustion Oxidation of sugars, fats and proteins for energy
Characteristics of redox reactions The oxidized substances…….. Lose electrons Increase oxidation state Is the reducing agent The reduced substances……… Gain electrons Decreased oxidation state Is the oxidizing agent